Building Stone Magazine

Residential
refinement

Calacatta Saturnia marble was favored to reinvent an antiquated
kitchen in a Massachusetts estate to a stunning living space that
functions for gourmet cooking and social gathering

BY JENNIFER RICHINELLI

54 | SPRING 2017 — Building Stone Magazine

When the time came to select
the material for the kitchen
countertops and backsplash in a
palatial home in Weston, MA, there wasn't
much hesitation before the decision was
made to use Calacatta Saturnia marble,
which was quarried in Brazil. From the
start of the kitchen remodel project, the
homeowners sought a stone that would
be the showpiece of the living space.
Collaboration between the architect,
interior designer and the kitchen design
team at Downsview Kitchens of Boston, MA,
was instrumental in realizing the kitchen
design, and "without the installation crew
from Hall, Dudley Builders and United Marble
Fabricators the execution would have been
impossible," according to designer Erica
Brady of Downsview Kitchens.

Brady describes the previous kitchen
as outdated and dark, and explained it
didn't optimize the use of the space. "Ad-
ditionally, the flow of the kitchen, in re-
sponse to the rest of the home, was a bit
disjointed," she said. "There were elements
of the previous kitchen that we all loved,
such as the built-in pizza oven, and knew
we wanted to keep. With that in mind, we
opened some walls, kept some, added
others and made the kitchen more func-
tional for the family. Our goal was to make
all of that happen, while being respectful
to the architecture and design aesthetic
in other parts of the home."

When recalling the selection choice
for the countertops, Brady said, "First and
foremost, it's stunning. The palate for the
cabinetry in the kitchen is neutral, with a
quiet elegance. To complement that, we
needed a rich stone to bring together the
various materials, including wood, high-
gloss lacquer, shiny metals, cool grays
and white leather, and make sure that the

Building Stone Magazine — SPRING 2017 | 55

Calacatta Saturnia marble — paired with wood, high-gloss lacquer, shiny metals, cool grays and white leather — transformed an outdated kitchen into a chic contemporary living
space for a Massachusetts family.

space didn't feel sterile. As soon as we saw their questions," said Brady. "Marble is an in- were white marble," he said. "Of all the
the slabs of Calacatta Saturnia, we knew it vestment, and it's human nature to care for options, Calacatta Saturnia was chosen
was the perfect fit." your investments. When a client chooses to to help convey a feeling of warmth in the
use marble in their home, they must under- crisp and striking kitchen. High-gloss, gray,
EDUCATING THE CUSTOMER stand that — as well as believing that mar- lacquered cabinetry, rich ebony wood,
Brady worked closely with the home- ble is like your favorite pair of jeans — it just brushed stainless metals and Calacatta
gets better with age. Marble isn't for every- Saturnia marble coalesced into a clean,
owners to narrow in on the Calacatta one, and part of my job as a designer is to modern, dramatic kitchen that is perfectly
Saturnia marble, which was supplied by know my client well enough to steer them suited for entertaining."
MIA+BSI member company Marble and toward it, or away."
Granite, Inc. of Westwood, MA. "Honest- In total, seven slabs were needed to com-
ly, it was such a quick decision because Downsview Kitchens turned to United plete the design of the gourmet kitchen.
it was so right." Marble Fabricators of Watertown, MA, to Brady and her client made a trip to United
fabricate the marble countertops. Echo- Marble Fabricators' shop to view the mate-
While the homeowners initially expressed ing Brady's words, John Kilfoyle of United rial before the cutting commenced.
some concern about going with a white Marble Fabricators described the selected
marble in the kitchen, the supplier was palette of materials as "a very raw combi- VIEWING THE SLABS
able to make them feel comfortable with nation of modern and industrial woods "It's important to prioritize, so in this case
their decision. "Marble and Granite is great and metals." "All of the initial stone options
about educating our clients and answering there was a big beautiful backsplash — it's

56 | SPRING 2017 — Building Stone Magazine

genuine versatile sustainable

unique easy to maintain durable

Simply put,
it’s the natural choice.

Want to learn more about the natural stone advantage?
Visit www.usenaturalstone.com,

your source for natural stone information and inspiration.

Powered by MIA+BSI.

"The undersides of both islands are exposed at the seating areas," explained John Kilfoyle of United Marble Fabricators in Watertown, MA. "These areas are also mitered and fully
polished underneath so that no visible area is dissimilar."

58 | SPRING 2017 — Building Stone Magazine

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A full-height backsplash creates a dramatic focal point in the estate's kitchen. an incredible focal point — so we had to
60 | SPRING 2017 — Building Stone Magazine start there by selecting the most beautiful
section of the best slab," explained Brady.
"From there, we talked about things like
parts of the slabs we want to avoid — ar-
eas that had imperfections, fissures, 'ugly'
spots, etc. We made sure they landed in
places that would be inconspicuous —
preferably a sink cutout. United Marble
Fabricators is experienced. It's a team ef-
fort; they know their product very well, and
I know what I want it to look like when it's
done. They help me understand my limita-
tions, while keeping the client's best inter-
est in mind."

According to Kilfoyle, the stove counter-
top was mitered to 6 inches thick and the
center island and perimeter countertops
were 2 inches thick. "This is an estate," he
said, when explaining the decision to use
mitered corners. "The ceiling is over 10 feet
high. It's a powerful kitchen. The team was
originally looking at 2-inch material, but
they were trying to push the limit of how
commanding they could make the kitch-
en look. The cooktop area is where the
full-height backsplash was placed. There
is a massive brushed stainless hood that is
6 1/2 feet wide and double ovens. It's the
whole show. They wanted that one to be
extra thick and the only way to do that
was by mitering."

The process of mitering involved bev-
eling the edges of each marble slab at
45 degrees so they join to form a corner
at a 90-degree angle. The aesthetic has
steadily grown in popularity over the
years in countertop production, specifi-
cally because of the clean, contempo-
rary look it achieves.

Once the cabinetry was installed, United
Marble Fabricators manually templated
all areas, said Kilfoyle. "A physical layout
was conducted with the design team in
our shop to discern the overall aesthetic of
the kitchen and to highlight the best parts
of the slab," he explained. "Once these
areas were determined, the kitchen was

digitized and drawn in AutoCAD. Scaled exposed at the seating areas. These ar- contemporary space like this one, flaws
high-resolution photographs were taken of eas are also mitered and fully polished tend to stand out even more," said Brady.
each of the seven slabs. The photos were underneath so that no visible area is dis- "United Marble Fabricators has great at-
imported into the CAD drawings to create similar." tention to detail, and they reworked a few
a photo-realistic layout of the entire kitch- areas because they felt it wasn't up to
en, which helped to ensure that all mitered WORKING TOGETHER their standards. I have to say, the space
edges flowed correctly. The slabs were cut Both Kilfoyle and Brady credit teamwork speaks for itself. If it looks easy, it's because
and mitered on a 5-axis bridge saw, the it wasn't." n
cutouts were completed on a CNC router for the success of the kitchen remodel,
and the mitered kitchen was assembled which recently was presented with the Kitchen Remodel
using mitreForma clamps from Integra "Kitchen of the Year" Pinnacle Award Private Estate
Adhesives." given by MIA+BSI. The installation of the Weston, MA
kitchen was a collaborative effort by all
"The full-height backsplash is captured trades working to beat a holiday dead- Builder: Dudley Builders
on all sides by cabinetry panels and the line," said Kilfoyle. "Our installers worked Kitchen Designer: Downsview Kitchens, Boston, MA
exhaust hood," Kilfoyle went on to say. inside of a fully occupied home alongside Stone Fabricator/Installer: United Marble
"The backsplash was fabricated at the many other trades, including millworkers,
same time as the countertops and was painters, home automation and flooring Fabricators, Watertown, MA
specially back cut and honed to mini- contractors, to complete the project." Stone Supplier: Marble and Granite, Inc., Westwood,
mize the chances of any damage to the
surrounding elements during installa- Fabrication and installation of the mar- MA (Calacatta Saturnia marble from Brazil)
tion. The undersides of both islands are ble countertops and backsplash were
completed in a span of two weeks. "In a

Building Stone Magazine — SPRING 2017 | 61

Restoring a city
landmark

The Arcade, located in St. Louis, MO, had been
abandoned for nearly 40 years before it was
transformed to house local workers, artists and students

BY JASON KAMERY

Photo Credit to John Flack of ByFlack Photography

62 | SPRING 2017 — Building Stone Magazine

Situated in the heart of the central
corridor of historic downtown St.
Louis, MO — across from the Old Post
Office — is The Arcade. A historic structure
of both local and national significance,
The Arcade is a 500,000-square-foot
building that was initially designed in 1913
by architect Tom Barnett. Original plans
were revised to integrate the adjacent
Wright Building of 1907, designed by
architects Eames & Young.

Named for the spectacular two-story
interior rib-vaulted shopping arcade, or
"interior street" inspired by the galleries of
Milan and Naples, Italy, The Arcade is one
of the city’s prime examples of a gothic
revival skyscraper. It was modeled on “a
city-within-a-city” prototype, creating an
area where people could not only live, but
do most of their shopping. The building
houses top-notch retail merchants in its first
six floors and office spaces in the upper
stories. In 2005, architect Paul Hohmann
had original plans to work on the building,
and started the project in September 2014
under the firm Ebersoldt + Associates.

The 15-month renovation project was
completed in December 2015 and
provided 282 new apartment units in
the upper floors and commercial and
educational space in the restored
two-story “arcade.” Designed to meet
the needs of artists and others with an
appreciation for the arts, the building
offers residents access to more than
11,000 square feet of shared artist studio
spaces, a 19th-floor rooftop terrace and
clubroom, and a wide range of other
community amenities.

Ford Marble and Tile provided a
historical restoration package, the main
goal of which was to use as much of the
site’s reclaimed stone as possible. After
an exhaustive inventorying process, the
company restored and refabricated 301

Building Stone Magazine — SPRING 2017 | 63

Ford Marble and Tile used 3,009 2cm ungauged floor tiles that were reclaimed and planed to a consistent 5/8-inch thickness as needed for a smooth transition on top of the
original, undisturbed mortar beds in extended hallways.

stone slabs, all in the onsite basement cladding application techniques for these had and they were all put back on with
fabrication shop created to minimize slabs in hallways and around elevators, plaster and copper wire. We did it with the
transportation risks. "All of the reclaimed and integrated 280 new panels seamlessly new pieces as well because you kind of
material we fabricated, we fabricated into the project as required. "When we had to — you were dealing with the old fire
on site," said Scott Ford, president of were sending material to the basement we block and it’s brittle so you can’t really use
Ford Marble and Tile. "We had to get had to remove all panels that were loose a mechanical anchor." Ford Marble and
the reclaimed material from every floor or leaning and had to number the wall Tile used 3,009 2cm ungauged original
down to the ground level and then took and the panel so we knew where it would floor tiles that were planed to a consistent
a crane at night and booned it through have to go back. Then we had to bring 5/8-inch thickness as needed for a smooth
a hole in the sidewalk where they were those panels back up from the basement transition on the top of the original,
doing electrical work. That’s how we after they were fabricated to reinstall them undisturbed mortar beds in extended
were able to get it all in the basement and had to replace the panels that were hallways, all from reclaimed material. For
fabrication shop. We had to move completely damaged. the showcase arcade on the mezzanine,
about 30 tons of material by hand and they were able to restore the missing
then could use the crane to move it into "When we took off the panels, we Spanish black marble and damaged wall
the basement." reinstalled them the exact same way they base from stone remaining on the first
did it in the 1920s," Ford went on to say. "We floor, where a new product was used. The
The project also utilized original wall drilled holes right next to the holes they

64 | SPRING 2017 — Building Stone Magazine

Ford Marble and Tile used 100 percent reclaimed and refabricated Tennessee Pink marble on the grand staircase for the wall base, stair treads, thresholds and surrounding floor tiles.

company used 100 percent reclaimed through 19, 3,773 square feet of White Also in the second through 19th floors,
and refabricated Tennessee Pink marble Carrara marble was employed. A total of 10,296 square feet of Bianco Gioia marble
on the grand staircase for the wall base, 60 panels were reinstalled from existing with a polished finish, from Carrara, Italy,
stair treads, thresholds and surrounding loose clad, and 51 panels were fabricated was used, and supplied from Global
floor tiles, except for two newly carved from salvaged cladding that was found Granite & Marble. The company also
marble newel posts ordered from Italy. onsite. A black marble was fabricated provided 1,753 square feet of Negro
The fabrication for the marble was done from salvaged base clad installed in the Marquina polished marble, quarried from
in the basement of The Arcade, which mezzanine — totaling 175 square feet. Spain, to be used as the cladding at
later became the building’s underground Additionally, a total of 1,989 square feet of the base of the building on the first floor
parking. For the adjoining marquee room reclaimed Tennessee Pink base clad was and the mezzanine. The wall cladding
that connects The Arcade to the elevator used for cladding on floors two through for the first floor and elevator lobby
lobby, new product had to be installed 19. For the flooring, 3,691 square feet of comprises 1,221 square feet of Beige
just within the marquee arch and expertly Tennessee Pink marble floor tiles were Rosato polished marble from Verona,
integrated to the original surrounding salvaged for floors one through 19. The Italy, also supplied from Global Granite
stonework and framed arch. project included 1,305 12- x 12-inch tiles, & Marble. Bruno Luchetti supplied the
1,480 10- x 20-inch tiles and 224 10- x 20- newel post from Beige Rosato and a first-
Four different types of stones were inch fabricated tiles from salvaged panels. floor grand staircase that used two slabs
salvaged for the project. On floors two

Building Stone Magazine — SPRING 2017 | 65

On floors two through 19, 3,773 square feet of White Carrara marble was employed. Construction on the $118 million renovation was completed December of 2015.
66 | SPRING 2017 — Building Stone Magazine

of the Beige Rosato. The slab flooring different shading of that material so that cently received the 2016 Pinnacle Award
and exterior entrances used 236 square we could find a happy medium shade. of Merit from MIA+BSI in the category of
feet of Absolute Black granite that was We sent it over to Italy and they could "Renovation and Restoration." n
given a flamed finish, and 295 square match it to the blocks they have so you
feet of 3-cm Dakota Mahogany granite wouldn’t really be able to tell a new panel The Arcade Building
that was flamed, both supplied by from an old panel." St. Louis, MO
Global Granite & Marble. Unique Stone
Concepts supplied 575 square feet of The building has 202 units set aside Architect: Ebersoldt + Associates Architecture,
2-cm Missouri Red granite that was used for artists, awarded based on income St. Louis, MO
for the exterior entrance cladding. "The qualifications and commitment to an art
size of the job was the hardest part of — anything from sculpting to writing to Fabricator and Installer: Ford Marble and Tile,
this project," said Ford. "You are talking makeup artistry. The building houses 80 New Athens, IL
19 floors and we used three blocks of luxury units that go at the market rates. The
material for the panels that were missing. Arcade Building’s first two floors and the Stone Supplier: Global Granite & Marble,
There was a tremendous amount of wall mezzanine house new Webster University St. Louis, MO (Bianco Gioia, Negro Marquina,
panels that had to be tied back in. When classrooms, a community kitchen, an art Beige Rosato, Absolute Black, Dakota Mahogany,
you do a project that size you’re going to gallery and a 170-seat auditorium. Missouri Red Granite); Bruno Luchetti, Italy
have shading. Back when they built it, I (newel post from Beige Rosato). Salvaged
don’t know how many blocks of material Construction on the $118 million renova- material found onsite (White Carrara, Black
they used for the project originally. So we tion was completed December of 2015. In Marble, Tennessee Pink)
took samples from three different floors of 1980, the building was designated a city
landmark, and in 2003 it was listed in the General Contractor: Paric Corporation,
National Register of Historic Places. It re- St. Louis, MO

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MADE TO LAST SINCE 1890 IN BARRE, VERMONT USA

Laying the groundwork
for the crown on
the National Mall

Granite provides a high standard of elegance, subtle security and quiet
permanence for a new Washington, DC landmark

BY SCOTT SOWERS

Photo courtesy of DC Real Estate

68 | SPRING 2017 — Building Stone Magazine

Building Stone Magazine — SPRING 2017 | 69

In 2009, Gustafson Guthrie Nichol (GGN), a landscape design firm with offices in Seattle and Washington, DC, won a design competition for the 5-acre site that would host the
National Museum of African American History and Culture. Photo courtesy of Rugo Stone

In 2009, Gustafson Guthrie Nichol benches, while also satisfying multiple the Commission of Fine Arts (CFA), who
(GGN), a landscape design firm with reviews, oversight, and security require- holds sway over the aesthetics and de-
offices in Seattle and Washington, DC, ments. From there, things became more sign of coins, medals, buildings and mu-
won a design competition for the 5-acre complicated, but the notion of using seums that are sited on the National Mall.
site that would host the National Museum natural stone was already etched onto
of African American History and Culture. the design boards. Mesabi Black® granite, quarried in
The prestigious plot of land is adjacent Babbitt, MN, was an early choice. Abela
to the Washington Monument and is Rodrigo Abela, a principal at GGN said, said, “We wanted something that was
bordered by Constitution Avenue, 12th “It’s an institution, so the ideas of per- uniform and fairly quiet. We wanted a
Street, Madison Drive, and 14th Street in manence and longevity are foremost. If stone that didn’t call too much attention
the Northwest quadrant of the city. you look at all the other museums in DC, to itself, but it’s a big space, so we wanted
there’s a standard this one had to live up to also create character and contrast.”
The basic landscape plan appeared to.” The stakes were high and the nation-
as a simple and elegant design pro- al stage beckoned as the design team Selling the CFA on Mesabi wasn’t that
viding walkways, retaining walls and submitted a pallet of material choices to hard, but there were other factors that
had to be weighed. “We didn’t have to

70 | SPRING 2017 — Building Stone Magazine

defend specific choices, but we had to The pathway up on the north side takes you past massive trapezoids of black granite bollards topped with bullnose
make a compelling case for an overall corners, a design detail that kept the team on its toes. Photo courtesy of DC Real Estate
composition,” explained Abela. “But at
the same time, these materials come
at a premium; there’s a budget and we
had to be strategic. Even though it was a
big-budget project, it was not an infinite
budget.”

As GGN worked their way through
the bidding and approval process
they leaned on several partners they
had worked with in the past, including
Coldspring, based in Cold Spring, MN.
The firm was selected as the source and
fabricator for the 37,000 square feet of
Mesabi Black granite used in the project.

Kayla Strand, Sales Coordinator for
Coldspring, said, “Black is a color that is
currently ‘in.’ Coldspring’s Mesabi Black
is a popular choice because it is one of
the darkest blacks that we quarry and
it is a domestic color. Mesabi also looks
great in many different finishes, so you
can get a contrast in color without using
a different stone.”

As everybody knows, there are many
shades of gray, even in stone, and
another material stepped up to play a
starring role based on a suggestion from
the installation team. Abela said, “Rugo
Stone, who did the installation, are
fantastic craftsmen — we reached out
to them when we were looking for stones
that would be appropriate and they
helped us find Impala.” Impala, quarried
in South Africa, has a similar grain
structure and crystal scale as Mesabi.

Brett Rugo, owner of Rugo Stone based
in Lorton, Virginia, and promoter of
Impala granite, said, “Any time you get to
work on Constitution Avenue, it’s a thrill.
There was a tremendous commitment to
doing a really high-quality job. It was a
demanding design with subtle, graceful
geometry in the site that doesn’t
look complicated, but it was actually
extremely challenging with a lot of large
radiuses and tight tolerances.”

Building Stone Magazine — SPRING 2017 | 71

Wide benches — also rendered from Mesabi — offer the weary a place to rest. Abela said, “We made these twice as wide and in various lengths, using the same stone, but we
polished the benches and expressed them as floating planes, then sculpted the supports down to a thinner leg.” Photo courtesy of DC Real Estate

The stonework on the site includes a mix of thin and thick retaining walls, benches, bollards and pavers, rendered in two kinds of granite in four different finishes.
Photo courtesy of DC Real Estate
72 | SPRING 2017 — Building Stone Magazine

As you get closer, rows of Mesabi pavers laid in a rectangular running bond form a hard surface around the museum’s combination oculus and water feature that channels sunlight
down into the structure’s lower levels. Photo courtesy of Rugo Stone

The stonework on the site includes a mix The pavers were finished in Coldspring’s at installation. Our CNC technology
of thin and thick retaining walls, benches, Diamond 10® configuration, which makes helped tremendously in the precision of
bollards and pavers, rendered in two it suitable for exterior application. these pieces. Once the pieces were cut
kinds of granite in four different finishes. to size, the polish finish was applied by
Underneath all the natural stone is a There is a slight slope to the site, with the hand to the bullnose. A lot of time was
lot of concrete. Rugo said, “A structural subtly curved retaining walls ringing the spent on hand finishing by our stone
concrete slab on grade is typical boundaries. Straight lines on the project craftsmen which definitely showed
throughout the site. There’s a 6-inch slab are few and far between. The concrete in the final product; which to me is a
with a 2- to 3-inch setting bed of dry pack pathway up on the north side takes you classic and timeless design.”
mortar. And then 2-inch stone paving past massive trapezoids of black granite
throughout, 3 inches in some cases.” bollards topped with bullnose corners, a The thicker retaining walls are anchored
design detail that kept the team on its by poured-in-place concrete walls. Rugo
The design team speaks about the toes. explained, “The open cavity walls are
project by breaking it down into discussions supported on stainless steel clips, top
about the north and the south sides of the Strand said, “Fabrication of the and bottom, with each stone backed to
museum and grounds. The north side faces granite pieces for the north wall proved a poured-in-place structural steel wall.
Constitution Avenue with two diagonal particularly challenging because of There is an offset dimension on most all of
walkways to the museum intersecting the wall’s slight radius and continuous the federal buildings that has a security
the corners of the block. One diagonal bullnose. We had to produce each berm built in place. Creative architects
walkway is concrete; the other is Mesabi. of these stones at precisely the same have been able to turn those from just
thickness to ensure an exact alignment

Building Stone Magazine — SPRING 2017 | 73

Mesabi Black® granite, quarried in Babbitt, MN, was an early choice. Photo courtesy Coldspring blocky bulky walls into elegant pieces of
art that provide a perimeter and also give
Rugo said, “A structural concrete slab on grade is typical throughout the site. There’s a 6-inch slab with a 2- to 3-inch setting definition to the limit of the property.”
bed of dry pack mortar. And then 2-inch stone paving throughout, 3 inches in some cases.” Photo courtesy of Rugo Stone
Rugo continued, “We did all the shop
drawings and shop tickets for those very
complex walls. Two-inches-thick wall
cladding; monolithic, massive copings
and caps cover the concrete walls,
and then at the end, very large pointed
buttresses 7 to 8 feet long by 4 or 5 feet
wide. These are very large, shaped
pieces. Those were all manufactured
using computer numerically controlled
(CNC) technology by Coldspring.”

The components of the complex wall
systems were first modeled using soft-
ware that provided 3-dimensional repre-
sentations of what the pieces would look
like and how they would fit together. A
5-axis CNC router was used to produce
the pieces. The design team used a pol-
ished finish on the tops of the wider walls
and a honed finish on the wall veneers.

Thin-profile retaining walls cut into
the slope and provide a border on the
pathways up toward the museum on
the north side. As you get closer, rows
of Mesabi pavers laid in a rectangular
running bond form a hard surface around
the museum’s combination oculus and
water feature that channels sunlight
down into the structure’s lower levels.

Wide benches — also rendered from
Mesabi — offer the weary a place to
rest. Abela said, “We made these twice
as wide and in various lengths, using
the same stone, but we polished the
benches and expressed them as floating
planes, then sculpted the supports down
to a thinner leg.”

The walkways around the building lead-
ing to the south side of the museum are
also bordered by a series of stunning yet
simple stone retaining walls that frame
the site, and landscaping elements.

The south side of the structure faces
Madison Drive, a smaller-gauge side
street that’s perfect for unloading bus-

74 | SPRING 2017 — Building Stone Magazine

es full of visitors. Guests find themselves visitors and the teams who helped bring well as our craftsmanship and experience
walking toward the porch — a large, it to life. have helped create a spectacular result.”
sheltering cantilevered-roof section that
shields a reflecting pool and large-for- The camaraderie of the team mem- The National Museum of African
mat scale pavers carved from Impala, bers comes through. Abela said, “I really America History and Culture received an
the other stone on the job. enjoy the process of building and inter- MIA+BSI 2016 Pinnacle Award of Merit in
acting with the trades. The drawings get the category of Commercial Exterior. n
Although the site appears to be simple you a good ways there, but that final five
and straightforward, the devil, as always, percent is built on the understanding of National Museum of African American
is in the details. Abela said, “Simplicity what everyone is trying to do.” History and Culture
takes work. Indoors, everything is level and
straight. When you get outside, everything Complex designs that look easy Washington, DC
has a slight slope because it has to drain brought out the best in the team mem-
water, and then you add a curve to that. bers. Strand said, “My favorite part Landscape Architect: Gustafson Guthrie Nichol
Stone guys work to the 32nd of the inch, about this project was the complexity (GGN), Washington, DC
so the biggest thing on this project was of the design. It posed challenges for us
accuracy. When laying out these curves at times, but the collaboration between Stone Supplier/Fabricator: Coldspring, Cold Spring,
there’s not a lot of tolerance.” GGN and Rugo Stone allowed us to hit MN (Mesabi Black® granite); Rugo Stone LLC,
this one out of the park.” Lorton, VA (Impala granite)
President Obama officially opened the
museum in September of 2016 and it cur- Rugo concluded, “our mission is promo- Stone Installer: Rugo Stone LLC, Lorton, VA
rently requires a timed entry pass for ad- tion of the use of natural stone and we General Contractor: Clark/Smoot/Russell Joint
mittance — which means it’s a hit with are very pleased that our help in bringing
both Impala and Mesabi to the project as Venture

nsvi.com

NATURAL STONE & MOSAIC EXTERIORS/INTERIORS BTehae uty Designing
CONTRACTORS COMMERCIAL/LITHURGICAL of Real Stone with Natural Stone
RESTORATION/RESIDENTIAL
VOLUME 7
WWW.RUGOSTONE.COM

Building Stone Magazine — SPRING 2017 | 75

Reinventing a campus
cornerstone

When restoring the University of Virginia’s rotunda, careful attention was paid to the carving of Carrara
marble columns, which shape the structure’s design

BY HEATHER FIORE

76 | SPRING 2017 — Building Stone Magazine

Photo courtesy of Anna Wesolowska-Hedman

A fter serving many years in public When Jefferson originally designed the original Carrara white marble, which
office, the third president of the the building, stone carvers from the proved unsuccessful over the course
U.S., Thomas Jefferson, founded Ricci family in Carrara, Italy, were of the next 100 years, as the capitals
the University of Virginia (UVA). As an commissioned to carve intricate designs eroded and the acanthus leafs of the
established architect who focused on into each of the 16 marble columns. Corinthian capitals began to fall off,
classical architecture, Jefferson helped However, in 1895, a fire destroyed much which are 30 feet above the rotunda
create the "academic village" at the of the rotunda, including the custom- entry platform. For safety reasons, the
UVA, which was completed in 1828. carved columns. American architect UVA clad the rotunda in a black screen
Stanford White of McKim Mead & White for many years following.
The village is a U-shaped complex of in New York City was subsequently hired
buildings located within the 28-acre cam- to design the restoration of the rotunda. In 2009, noted historic preservation
pus that sits on an elevated slope and in- While he did an impressive job, the architectural firm, John G. Waite
corporates a rotunda. The rotunda, known construction team in this era opted to Associates, Architects (JGWA) in Albany,
as the centerpiece of the university, was use an alternate source for the white NY, was tasked with restoring the rotunda
inspired by The Pantheon in Rome and marble capital replacement, in lieu of back to its original luster. "It's the visible
features 16 solid white marble capitals. symbol of the university and a much

Building Stone Magazine — SPRING 2017 | 77

For the rehabilitation of the rotunda at the University of Virginia (UVA), which was completed in 2015, the main focus was replicating the marble capital columns that were incor-
porated into the original design from the early 1800s.

Since an 1895 fire destroyed the majority of the building, the architects and stone fabricators only had partial columns and fragments to work off of, as well as a couple of old
photos. To begin, three-dimensional digital scans of a capital base and three smaller upper capital fragments of existing 1823 capitals were taken, creating a one-quarter-round
composite marble and clay model. Photos courtesy of JGWA
78 | SPRING 2017 — Building Stone Magazine

beloved building," explained John G.
Waite, FAIA. "It's also the last building
that Jefferson designed before he died.
It was designed to serve as the symbol,
as well as the heart and soul, of the
university."

Positioned in the front of UVA's campus,
the rotunda houses the library on its
upper levels and lecture rooms on its
lower floors. "The building has symbolism
on all levels," said Waite. "Every other
college that was done before then
and at that time always had a chapel
in the design that was prominent. The
University of Virginia did not, and the
rotunda symbolically was the chapel, the
cathedral of the university; Jefferson was
not a great fan of organized religion."

REVIVING THE ROTUNDA After the model was crafted, a two-dimensional hand drawing was completed to detail all the ornament on Corinthian
With a failed attempt to repurpose the capitals, followed by the development of a full-round three-dimensional digital shop drawing. Lastly, three-dimension-
al full-round CAD files were used to CNC route solid bocks up to 80% complete, leading to the careful hand carving of
structure in the late 1970s, which would 16 full round capitals, which each weigh 6,300 pounds and measure 4' 8" x 4' 8" x 3' 10." Photo courtesy of JGWA
have converted it to a president's office,
the rotunda was most recently designed Waite. "After 1895, White took those spaces, RECREATING A 150-YEAR-OLD
to serve as the hub for student activities, which were all destroyed, and built what is STRUCTURE
containing classrooms, seminar rooms called the 'Terrace,' rooms around a court-
and a library. "The goal was to make it yard that are considered to be historic in In 2013, after the extensive design
once again as Jefferson intended, an in- their own right. We gutted those additions process, Rugo Stone, LLC, in Lorton, VA,
tegral part of the students experience at and put in new classrooms and administra- was selected to aid JGWA with the res-
the university," the architect explained. tive office spaces — modern spaces that toration, particularly with the supply and
"The key part was to replace the marble can be altered in the future." carving of marble that was used. "We
capital columns which were disintegrat- came as close as we could to the marble
ing. For the first two years, we did a his-
toric report, which included researching
everything to find out about the original
construction and modifications over the
years. We did a very detailed analysis of
the building as well — what was historic,
what wasn't, what was put in as part of
previous restoration that wasn't accu-
rate and reflected what Jefferson want-
ed — and out of that came the program
and the design of the restoration."

JGWA paid careful attention to the histo-
ry of the building and renovated it to reflect
what the original plans included. "When
Jefferson originally designed the rotunda,
there was a gymnasium behind a wall," said

Building Stone Magazine — SPRING 2017 | 79

Representatives from Pedrini, Rugo Stone, JGWA and the UVA observe the completed prototype in Carrara, Italy. A couple of weeks were spent on each section of the capital, ac-
cording to the architect. "The top was more critical because it projected more design elements," he said. Photo courtesy of JGWA

that Jefferson used in 1825," said Waite. Bill Lazar, vice president of operations would have carved in 1825," Lazar went
With the main focus on replicating the at Rugo Stone. "There were no close-up on to say. "It is also important to know that
photos, just an image from 1895, which as much as the intent was to replicate
marble columns, Rugo Stone and JGWA showed the capitals at a 100-foot dis- the original capitals, the preference was
began by foraging through old photo- tance. There were also no original draw- to provide the new capital as a single
graphs, since there wasn't one complete ings and architectural design plates, piece of marble."
column intact. "All we had to work with which would confirm the original design.
was one partial lower capital base and "Each capital was an individual design.
two or three small fragments from the up- "This is a critical point to understand, as There wasn't enough physical informa-
per portion of the upper capital, as the the overriding design goal of the project tion to put the pieces together and figure
original capitals were fabricated in two was to replicate what Jefferson would out what a column capital was originally
portions (lower and upper)," explained have designed and what the Ricci family like," Waite added. "We had pieces and

80 | SPRING 2017 — Building Stone Magazine

Once the prototype was tweaked and approved, professional sculptors at Pedrini srl in Carrara, Italy, created a full-size mock-up in the Carrara C marble from the Campanili
Quarry. Photo courtesy of JGWA

Several months were spent on the carving and creation of the 16 marble capitals, which were then carefully transported over to the UVA.
Building Stone Magazine — SPRING 2017 | 81

Since the height and width of the entry to the rotunda was limited, Rugo Stone created a lateral conveyance system to remove the existing capitals and replace them with the new
ones. Photo courtesy of JGWA

really clear photographs from before the the base portion," said Lazar. "Once the The partial capital was then reproduced
fire which we were able to enlarge. We two-dimensional drawing was approved, in Carrara C marble from the Campanili
then generated three-dimensional com- Pedrini created a marble model of the Quarry, followed by the full round Corin-
puter designs based on the photographs, lower portion of the capital in a one- thian capital.
field dimensions we took and fragments." quarter round. A clay model for the upper
portion of the capital, in a one-quarter "This capital became the basis of com-
Rugo Stone has a close relationship with section round, was created on top of the parison for the next 15 capitals, which
a Carrara-based stone fabricator, Mario marble lower portion to provide a full were carved over the next 10 months,"
Pedrini srl, who were able to reproduce height one-quarter model in marble and said Lazar. "Pedrini used two 6-axis ro-
the original columns using the three- clay. Through multiple designer visits to botic machines to shape the column
dimensional, digitally scanned images. Carrara, the clay and stone model was capitals, and the remaining 20 percent
"Pedrini and their artist, Mr. Gianluca approved." of the work was performed by a skilled
Ceccarelli, prepared a two-dimensional, team of ornamental carvers. The carving
full-scale hand drawing of the Corinthian Waite, who traveled with Rugo's team of the capitals is a perfect example of
capital, used by the design team to Italy, said they spent more than one Pedrini's use of modern machining and
to develop a proportionally correct week observing the final prototype, mak- traditional hand carving to produce
development of the upper portion of the ing little changes wherever needed to highly ornate capitals in an unprece-
capital, which was more complex than ensure the precision of the new capitals. dented short time period."

82 | SPRING 2017 — Building Stone Magazine

INSTALLATION FEATS The finished product is a stunning replication of the original columns from the 1820s.
Once the capitals were produced, in-

stallers were tasked with removing all ex-
isting column capitals and replacing the
new capitals with virtually no overhead
space, given the low profile of the rotun-
da's portico roofs. "The real challenges
were to get the mechanical systems in
and excavate under the building," said
Waite. "You have no idea mechanical
facets are below the building; they're
completely invisible. The rotunda itself
is put back exactly as it was historically."

Since Rugo was limited to the height
of its machinery, specifically its crane,
the installation team had to create a
lateral conveyance system to transport
the capitals using a mobile crane and
steel channels. "The lifting method was
also highly customized and involved a
crated steel cart with hydraulic jacks,
which lifted the existing capitals off the
columns and allowed for the placement
of the new capitals," said Lazar.

Although the entire project took more
than two years to complete, the installation
of the columns took only a couple of weeks
and required just five men. "The rotunda has
been classified by the United Nations as a
World Heritage Site and UVA remains the
first and only American collegiate campus
to have this status," said Lazar. "It can be
argued that the UVA campus, specifically
the rotunda, is one of the most important
architectural structures in the U.S." n

University of Virginia rotunda renovation "The carving of the capitals is a perfect example of Pedrini's use of modern machining and traditional hand carving
Charlottesville, VA to produce highly ornate capitals in an unprecedented short time period," said Bill Lazar, vice president
of operations at Rugo Stone.
Architect: John G. Waite Associates, Architects,
LLC, Albany, NY

General Contractor: Whiting-Turner Contracting
Co., Baltimore, MD

Stone Fabricator: Mario Pedrini srl, Carrara, Italy
Stone Supplier/Installer: Rugo Stone, LLC, Lorton,

VA (Carrara C marble from Campanili Quarry in
Carrara, Italy)

Building Stone Magazine — SPRING 2017 | 83

CONTINUING EDUCATION

Houston Museum of Natural Science
Exterior cladding made from natural stone can offer both an aesthetic beauty and sustainable surface to the building, and the anchorage system holding the material in place is a
critical feature. All images courtesy of MIA+BSI: The Natural Stone Institute

Understanding Anchorage CONTINUING EDUCATION
Systems for Natural
Stone Cladding 1 AIA LU/HSW

Knowing how anchorage systems work, their main components, 1 GBCI CE Hour
and the difference in system types is critical for designing and
engineering a natural stone cladding system IDCEC CEU. CREDIT IS ALSO ACCEPTED
BY THE ASID,IIDA AND IDC.
SPONSORED BY MIA+BSI: THE NATURAL STONE INSTITUTE | BY ANDREW A. HUNT
BNP media is authorized by iacet to
One of the greenest building materi- it an ideal material for green building proj- offer 0.1 ceus for this program
als available is natural stone, espe- ects. Dimension stone is natural rock that
cially when sustainable extraction has been quarried in prespecified block or Learning Objectives
practices are considered. The material itself slab sizes and finished to certain specifica- After reading this article, you should be
is taken straight out of the earth from quar- tions and requirements. able to:
ries. From there, it is cut to size, finished, and 1. Discuss the main external forces that
installed as everything from countertops INTRODUCTION TO NATURAL STONE
and flooring to fireplace mantles, back- AND ANCHORAGE SYSTEMS affect natural stone cladding, and explain
splashes, walkways, garden walls, and ex- why anchorage systems are needed to
terior cladding. Stone is low maintenance, Today, one ideal use for natural stone is in create a durable installation.
easy to clean, and can offer a long lifetime exterior cladding. Whether it is used to help 2. Describe the three elements of a natural
of protection, beauty, and service, making reduce a building’s heat island effect in a hot stone anchorage system that ensure a
and dry climate, or to provide a water- and safe and long-lasting exterior cladding
installation and that can support
sustainable building practices.
3. List the various types of natural stone
anchorage systems available.
4. Explain the importance of proper fill used
around the anchorage embedments to
ensure a durable and sustainable exterior
cladding system.

To receive AIA credit, you are required to
read the entire article and pass the test.
Go to http://bit.ly/AnchorageCEU to
take the test for free.

AIA COURSE #K1612R
GBCI COURSE #0920011497
IDCEC COURSE #CC-105935-1000

84 | SPRING 2017 — Building Stone Magazine

freeze-resistant exterior in a colder climate, CONTINUING EDUCATION
exterior stone cladding is versatile and
appealing. The raw and authentic appeal Northwestern University Bienen School of Music, Evanston, Illinois
of stone lends itself to bold and interesting Whether inside in a protected environment or outside, the forces of nature are constantly working against cladding,
design options, while also satisfying the making anchorage systems a critical safety and sustainable element of design.
structural needs of the building.
considered one of the most sustainable concept than gravity, and it is much more
Natural stone cladding requires a safe, products available. complicated to predict and protect against.
secure, and durable anchoring system. When wind encounters a building, it exerts
When used as a cladding, the weight of As a dense, strong, and durable product, pressure on the walls—and thus the clad-
the stone is subject to several forces that natural stone works well as an exterior clad- ding. This pressure can be both positive, with
it must be able to resist—namely gravity, ding. However, in order for the cladding to the wind pushing directly on the cladding, or
wind pressure, and seismic loads. To ensure be safe and secure, it needs to literally be negative, with the wind pulling outward on
a safe and durable stone cladding project, safely secured to the building structure by the wall, or essentially “sucking” the clad-
architects need to understand how natural anchorage systems that can withstand the ding. In most cases, negative wind loads on
stone anchorage systems work, what key forces that impact natural stone cladding. buildings tend to be stronger than positive
components are involved, and how to work loads. Corners and areas with raised or low-
with engineers and installers. FORCES THAT IMPACT NATURAL ered surfaces typically experience the high-
STONE CLADDING est loads. The pressure that is put on the clad-
FORCES THAT IMPACT NATURAL ding depends on the building design. Wind
STONE ANCHORAGE SYSTEMS Stone cladding panels will be subjected loads are expressed in terms of pressure, ei-
to gravity and to applied loads, such as ther in pounds per square foot (lbs/ft2) in U.S.
Forces such as gravity, wind load, and wind load, thermal movement, and seismic customary units, or in pascals (Pa) in SI units.
seismic activity all can negatively impact movement—anything that impacts the
natural stone cladding and anchorage sys- building’s structure. The three primary forc- With dimension stone cladding, the wind
tems if the building team does not consider es that can affect the safety and security loads will always be proportional to the area
the potential impact of these forces. One of of natural stone cladding are gravity, wind of the stone panel. This means that a strong
the best ways to ensure success is to hire an load, and seismic load. wind on a large panel will exert more force
accredited stone installer to work with the than the same wind on a smaller panel. In
project’s structural engineer and architect. Gravity is an obvious force and is best cases with negative wind pressure, force on
These team members are better suited for understood by considering the very physi- the stone can act in inverse, creating suc-
understanding the specific needs of the cal characteristic of stone as a heavy ma- tion. Depending on the geometry of the an-
anchorage system and can ensure the final terial. Gravity is a vertical force, and it is chor clip design, in some cases, wind loads
product remains structurally sound for years proportional to the mass of an object—in can exert forces on the anchor clips that
to come. this case, a stone panel. The heavier the are cumulative with the gravity forces. This is
stone, the more work the anchor needs to always the case when negative wind loads
With that in mind, let’s take a look at do to secure it to the structure.
how nature impacts stone cladding, and
how choosing natural stone as a cladding Wind load is a slightly more complicated
material inherently brings strength and
durability to a project.

THE INHERENT QUALITIES OF
NATURAL STONE

As a natural product, stone is inherently
eco-friendly. While it needs to be cut and
finished, the material itself is “ready made”
right out of the earth. Stone is naturally
very strong, durable, and easy to maintain.
When best practices are used for extraction
and manufacturing, natural stone is

Building Stone Magazine — SPRING 2017 | 85

CONTINUING EDUCATION of the stone. As with gravity, this load is
also proportional to the mass of the stone
Tarrant County Civil Courthouse, Fort Worth, Texas panel. Because seismic activity is not usu-
When installing exterior natural stone cladding, to ensure safety and durability, each piece of the load path is impor- ally associated with high-wind events,
tant, and building professionals should understand how each works individually, as part of the building system, and in standard building codes rarely require
response to the various forces. that building design consider a combina-
tion (or cumulative) load of seismic and
are experienced by soffit stones. A building’s and aftershocks, and they are unques- wind loads. That said, in cases where forc-
size, shape, height, location, and neighbor- tionably the most complicated loads to es perpendicular to thin stone cladding
ing buildings all can influence wind loads. determine since the load can be both faces are expected, the wind loads in
perpendicular and parallel to the face most cases will be greater than potential
Seismic loads stem from earthquakes seismic loads, and thus will govern most
design decisions.

Building codes for seismic loading vary
among locations. Some regions are prone
to significantly strong earthquakes, which
can exert extreme force on the buildings
and the exterior cladding. Compared
to regions where earthquakes are infre-
quent, these buildings will have much
higher seismic load requirements. These
requirements are determined by the prob-
ability of seismic action and the maximum
possible intensity of the quake.

Getting a feel for rock Natural stone cladding can help a building
blend into the local environment when
Natural stone comes in many varieties, and it is important to understand the characteris- native stone is used. Here, New Mexico
tics and qualities of each type used in construction today. travertine and limestone are used to match
• Granite can be found in hundreds of colors, and it is one of the hardest natural stones. local geography around the Associated
Students of New Mexico State University
This combination of color and durability makes it an ideal material for everything from Center for the Arts.
monuments, curbing, and building facing to fireplaces and countertops.
• Limestone’s uniform texture and grade make it a widely accepted dimension stone, in
part because it can be easily cut, carved, and shaped into almost any design. Moreover,
its homogenous nature and natural tendency to look better as it ages makes it a great
choice for projects that may eventually be expanded.
• As with limestone, marble is a highly versatile stone that can be used for both interior and
exterior projects. It can easily be shaped and sculpted, and it holds its beauty for a very
long time. Marble is not as hard as granite, but it is hard enough to be used for flooring,
countertops, backsplashes, and shower areas.
• Sandstone is a softer, user-friendly stone that has become popular as a wall cladding
material and for flooring. As its name suggests, sandstone is made of sand-sized clasts,
and while it can be a variety of colors, it is most commonly available in tones ranging from
white and gray to tan and brown.
• Slate has a long history of use in construction projects because of its strength and density,
which makes it a great choice for exterior cladding and roofing. Slate is frequently used
for interior projects such as countertops, shower enclosures, and flooring.

86 | SPRING 2017 — Building Stone Magazine











CONTINUING EDUCATION Effective joint width
is maintained by
fitting angle and
shims into rebate
space

Shelf angle with rebated stone Bent stainless plate Welded stainless steel “T”

Clip or shelf angle anchors work by supporting the Bent stainless plates are ideal for projects where A variation on the bent stainless steel plate is a
stone’s dead load via short, thick L-shaped metal clips. corrosion may weaken the anchorage system. welded plate.

sandstone, in cubic thickness (greater or happen when metal comes in contact with surrounding spaces be allowed to ac-
equal to 3 inches, or 75 millimeters). With different types of stone are listed below. commodate movement.
softer stone, plug anchors are known to These examples can be used as a starting
be significantly stronger than other types point for considering anchorage options for Sealants can be used to weatherproof
of back anchors. natural stone. joints between the stone panels and any
adjacent components. This sealant will be
APPLICATION AND MATERIAL Calcareous stone types such as limestone
INFLUENCE ON ANCHORAGE SYSTEMS and marble are prone to corrosion when in Installed strap anchor
contact with certain untreated metal com-
Regardless of the anchor type, it is critical ponents. Any metal used must be coated or Strap anchors are flat metal bars that are designed to be
that contact between the minerals in the sheathed with a compound that does not inserted into a kerf (slot) in the edge of the stone panel.
stone and the metal be controlled to pre- react with the stone (or other cladding ma-
vent corrosion of the metal, which would terials). Moreover, the coating must be com- Pictured is an example of an anchor failing due to the
compromise its strength. As noted in the patible with the joint sealant. However, not bolt placement too far from the bend.
descriptions of the various anchor types, all metal components are vulnerable to cor-
these systems may be both ferrous and rosion; for example, stainless steel types 302
nonferrous, and components most often in- and 304 can be used without any protection.
volve stainless steel or aluminum. The issue
of corrosion is directly linked to the applica- Aluminum alloys can be problematic if
tion and material influence on the anchor- they come into contact with both moisture
age system, mainly in that different stone and certain stone minerals. For example,
types are more prone to moisture pen- when used with calcareous or calcitic
etration or have mineralogy that affects stone, aluminum can potentially corrode,
the metal of the anchor more than other even if it has first been anodized.
stone types. Consequently, installers need
to consider the combination of anchorage Corrosion can also happen if inappropri-
systems and stone types in the context of ate components come in contact with sili-
specific climates and environments. For ex- ceous stone, such as granite, and if moisture
ample, limestone in an arid climate will be is present. As such, noncorroding materials
less susceptible to corrosion than in a more must be used.
humid or wet climate. Architects should
be aware of possible corrosion issues and As the saying goes, a chain is only as strong
discuss the possibility with the project’s as its weakest link, and the same holds true
structural engineer and the stone installer for anchorage systems.
before finalizing any decisions.
ANCHORAGE SYSTEM FILL AND
Some examples of problems that can FINISH WORK ON NATURAL STONE

Anchorages for natural stone clad-
ding typically require that the joints and

92 | SPRING 2017 — Building Stone Magazine

Going green with natural stone CONTINUING EDUCATION

Natural dimension stone is considered a prime building material for many reasons, including the diversity of colors, patterns, and
textures, as well as its unmatched durability. In addition to the aesthetic and durability attributes, natural stone such as granite,
marble, limestone, sandstone, and slate all have characteristics that contribute toward LEED certification or LEED construction. For
example, stone is a natural product, and in many cases it can be obtained relatively close to a building site, which can reduce
carbon emissions from shipping a material over long distances. Sustainable quarrying practices can be put in place to help pro-
tect the local environment during extraction and to reclaim the site once extraction is complete.

Other green attributes of natural stone stem from the material’s physical properties. For example, because it is not manufac-
tured, stone poses no risk of chemical off-gassing. This characteristic makes it desirable for interior projects. Natural stone is useful
for exterior projects such as cladding as well, in part because of its high thermal capacitance, which can help with a building’s
energy efficiency requirements for green building certification. Stone’s durability and low maintenance provide green benefits for
both interior and exterior projects. Durability translates to a long material lifespan; unlike some manufactured products, it doesn’t
need to be replaced and should last the lifetime of the building. Not only is stone low maintenance, its aesthetic attributes often
improve with age, and again do not require much in the way of treatment.

In addition to the physical properties of the stone itself, new fabrication techniques have made it easier and faster to cut the
stone in thinner and more precise slabs. These advances have developed in tandem with new anchoring systems, which have
greatly reduced the installation time and difficulty of stone cladding, and which have also improved the safety, security, and
durability of the cladding once it has been installed on the building exterior.

wet when applied, but will cure “soft,” func- cure rapidly (often within 30 minutes) and Aluminum Unitized Anchorage System
tioning as a gasket to insulate movement are appropriate for many projects. That
and serving as a buffer between cladding said, they may be vulnerable to swelling or system. This characteristic is beneficial for
elements so that forces are not transferred erosion when exposed to moisture, and thus projects where the stone cladding may re-
between the parts. may be inappropriate in certain environ- quire very flexible connections.
ments or for certain projects.
The filler material resides in the anchor Shims work as physical spacers. They are
prep and displaces the void between the Resinous fillers, or adhesives, usually refer typically made of either stainless steel or
penetrating anchor and the interior walls of to epoxy. These fillers are more expensive the more popular high-density, high-impact
the anchor prep. than other options and typically have slow plastic. Regardless of whether the shim is
cure times. There are known problems with made of stainless steel or plastic, it must be
Gypsum-based fillers were popular sev- the high level of rigidity of epoxies in their able to bear the load without deforming. In
eral decades ago but are no longer consid- cured state, which has been associated some cases, shims are used to provide ad-
ered appropriate for natural stone cladding. with increased stresses near the anchor ditional support, while other types of fillers
Exterior cladding that was installed during prep as a result of limited flexibility. These cure, after which the shims are removed.
the era of gypsum-based fillers reveals that factors make epoxy appropriate for certain
the material has a low strength and is vulner- anchorage systems, but not others. For ex- THE FUTURE OF ANCHORAGE SYSTEMS
able to swelling or erosion if exposed to even ample, they are safe for securing dowels in As the building industry continues to “go
a small bit of moisture. cubic stone sections, such as stairs pieces,
which are supported by the structure below,
The combination of gypsum-based ma- but they are not appropriate for thin stone
terials with portland-based products should cladding, where the requirements for a flex-
be avoided. The combination of the two ible connection come into play.
materials will create a hybrid known as “ettr-
ingite.” Ettringite has the unusual property of Elastomeric fillers, such as silicone and
having a greater volume than the sum of the polyurethane sealants, are popular choices
two parent components, and thus expands. for filling anchor preps in part because they
are flexible in their cured state and allow for
Cementitious fillers, such as portland dynamic movement within the anchorage
cement-based setting grouts, are common
and easily available. These fillers tend to

Building Stone Magazine — SPRING 2017 | 93

CONTINUING EDUCATION green,” anchorage systems will follow the think about choosing an anchorage sys-
trend, especially as new materials are put tem. If for some reason test data for the
into use. One change on the horizon is low- or Pictured is an example of bent stainless steel shapes stone isn’t current or reliable, they must plan
zero-VOC chemical anchors as an alterna- installed in stone cladding. to test the stone before selecting it. Once
tive to traditional adhesives. Eliminating vola- this is done, they can determine the panel
tile organic compounds in chemical-based decisions, and they must include accred- size and thickness that best complements
anchors and adhesives is particularly impor- ited specialists in the process from the very the physical characteristics of the stone.
tant for interior installations, and the change start of the project. There are many methods
can positively affect awarded LEED credits. used for anchoring dimension stone, and Only after these tasks are complete should
Another modification to chemical adhesives the components for each vary. Moreover, they choose an anchoring system that is
is an “improved UV stability” designation. Any the installation of the cladding is only one prescriptively designed by the architect or
adhesive material that is exposed to sunlight of the many elements of a complete wall contractor, or the architect can specify a
is also exposed to UV radiation, and over time system. Every component of the wall must proprietary panelized system. If the archi-
the adhesive will change color. Newer prod- be considered when deciding which an- tect specifies a system, they must shoulder
ucts will minimize or eliminate this problem. chorage system will be best for the project. the risk and responsibility of the choice. A
For example, building professionals must first good team that includes a structural engi-
Two other areas of innovation are in the select a structurally viable building stone for neer and a stone installer is critical for the
cure rates of adhesives and improved deliv- their respective project before they even success of the project. n
ery systems. Many new adhesives now cure
much more quickly than traditional options. Andrew A. Hunt, vice president of Confluence
The trend is toward strong adhesives that Communications, has 16 years of experience in
cure quickly and safely. Meanwhile, other green building and has produced more than
companies are exploring ways to improve 100 educational and technical publications.
how the adhesive is mixed and dispensed, confluencec.com
with the aim of reducing waste. For exam-
ple, an improved trigger mechanism on the MIA+BSI: The Natural Stone Institute offers a
adhesive gun makes it easier to squeeze, wide array of technical and training resources,
which results in less wasted material. professional development, regulatory advocacy,
and networking events for the natural stone industry.
CONCLUSION www.naturalstoneinstitute.org
In conclusion, one of the most important
http://www.marble-institute.com/accreditation/
takeaway messages for architects consid- accredited-companies
ering using natural stone exterior cladding
is that they must work closely with the struc- Take quiz at http://bit.ly/AnchorageCEU
tural engineer for material and anchorage

Pulling stone

Natural dimension stone is most often quarried rather than mined since it lies close to the surface and thus is moderately easy to
extract. Modern quarrying technologies and practices are much more precise and efficient than they used to be. For example,
diamond wires and saws can cut stone to exact dimensions with very little waste. And the practice of using whatever is produced,
whether it is dust or aggregate, for the production of materials such as plaster, cement, or fertilizer adds to the overall sustainable
nature of the practice. Moreover, responsible, sustainable stone companies will ensure that the quarry site is eventually reclaimed
for other purposes, such as wildlife habitats, recreation areas, or parklands.

Once natural stone has been extracted from the quarry, it is cut and finished according to whatever specifications are required.
In the case of natural dimensional stone for exterior cladding, the individual stone slabs will be cut to a designated thickness and
finished in any number of ways, whether blasted and shaped with water, polished and buffed, or sandblasted. Exterior cladding is
often prepared using a split-face technique, where the stone is split either by hand or with a machine to reveal its natural texture.
This technique enables a flat back, which can be easily anchored to the building structure and an uneven, “natural” front surface.

94 | SPRING 2017 — Building Stone Magazine