time. If it is cut to fit during the installation
process, all you see is stone inside, unlike
manufactured stone, where the aggregate will
be exposed under the same circumstances.
Natural
Stone Thin Veneers
Natural stone is a timeless material that has
been used for centuries in structures of all
types. In one of the fastest growing segments
of the masonry products market, adhered
stone veneers have become increasingly
popular during the past decade in both
commercial and residential construction.
The slim profiles afford builders, architects
and designers with new options for interior
and exterior wall design, both in remodeling
and new construction. Compared with full
dimension stone, natural thin veneers offer
substantial benefits, particularly in terms of
engineering, shipping and installation.
A thin veneer is any lightweight, thin surface
material that can be applied directly to a
solid facing. In contrast to full dimension
stone masonry ranges upwards of four inches
in depth. Natural thin stone veneer averages
in thickness from 3/4-inch to 1-1/4 inches,
and must weigh 15 pounds or less per square
foot as mandated by the Uniform Building
Code (UBC). The elimination of a load-bearing
foundation requirement equates to less
engineering costs because of the reduction
of structural reinforcements required.
Thin stone veneer is ideal for areas that
cannot support a heavy load, and it is a
viable alternative for projects with limited
space. Typically, thin veneer is sold in flat
and corner pieces to provide flexibility in
design and authenticity in aesthetics, as the
product may be wrapped around a column
or wall, providing a look similar to fulldimension stone.
Quarried from the earth
Natural thin stone veneer is quarried
from the earth. The fabrication process
has advanced technologically in the last
few years by incorporating diamond saws
and computers into the process. The best
manufacturers also test thin veneers for
freeze/thaw for use in all climates across the
United States and Canada, in addition to
adhering to strict specifications to ensure a
consistent final product.
Because it is a natural product, the unique
color of natural thin stone virtually eliminates
the potential for repeating patterns on
large projects. The other important quality
of natural stone compared with the
manufactured variety is that natural stone
veneer is colorfast and will not fade over
Natural thin stone veneer is durable with
very little water absorption, eliminating the
tendency to show efflorescence, which is a
white, powdery deposit that can appear on the
face of masonry walls. Natural stone veneer
also is shown to outperform the manufactured
alternative in several parameters, including
compressive strength and freeze/thaw
durability. Comparative data indicate that
manufactured stone absorbs significantly more
water per unit of weight than natural stone, and
natural stone expands more over time, while
manufactured stone tends to shrink because of
drying and carbonation.
Styles of natural stone thin veneer
Natural thin stone veneer is available in a wide
variety of styles and colors. The most prevalent
shapes on the market include fieldstone, ashlar,
and ledge stone. Fieldstone is characterized
by irregular shapes set in a random pattern.
Ashlar (Castlestone) styles are composed of
larger, rectangular pieces with square edges
and flat surfaces. Ledgestone typically consists
of longer pieces of
stone with varying
heights and depths.
Blending or mixing
several types of
stone together
can achieve a
distinctive look.
Natural thin
veneer also can be
trimmed during the
installation process
to obtain precise detailing objectives.
per day compared with just 40 to 60 feet of
full veneer. This variance affords a significant
opportunity to increase labor efficiencies;
since faster installation means the same
crew can take on more jobs in the same
period of time.
With rising fuel prices being felt across
the nation, transportation costs are an
increasingly important variable in specifying
building materials. Because of its smaller
size and weight, more thin veneer can be
shipped per truckload. For example, a truck
traveling from Denver to Atlanta can haul
enough full-depth stone (typically four
inches deep) to cover 1,000 square feet of
wall surface, or enough thin stone veneer
to cover 4,000 square feet. Generally, that
translates to a reduction in transportation
costs by a factor of four.
Natural and Manufactured Stone Property
Comparison Stone
*Natural Stone includes Sandstone,
Limestone, Marble and Granite
*ASTM Requirement values for Natural Stone;
ICC Acceptance Criteria for Artificial Precast
Stone Veneer;
*Maximum Density for all veneer is 15 psf per
UBC/IBC
* Shrinkage and
Expansion in inches
per 10 ft section.
Natural stone usually
expands over time due
to moisture uptake;
manufactured stone
always shrinks over
time due to drying and
carbonation.
* Products are
packaged under the assumption that a 1/2inch mortar joint will be used in installation.
Dry stacking the materials will require about
30 percent more product.
Note: Pangaea Natural Stone Inc. packages
and sells all Natural Stone Thin Veneers as a
dry stack.
With a life span of more than
1,000 years when properly
designed and built, natural thin
stone veneer provides longevity
to homes and buildings.
Cost savings implications
Since natural thin stone veneer is considered an
applied veneer as outlined by the UBC mandate
of weighing 15 pounds or less per square foot,
there are several areas where the cost of the
structure can be reduced. By eliminating the
brick ledge, which is required for full-dimension
stone, there will be less engineering involved,
affording cost savings during the design
process. The elimination of the brick ledge also
will result in a savings because of less concrete
and rebar being utilized during construction. In
addition to engineering and construction cost
savings, there are other cost savings advantages
to using a lighter weight of thin veneer product
in building, including ease of installation and
reduction in transportation costs.
Natural thin stone veneer is easier to install
than its full veneer or full-dimension masonry
counterparts, and it installs using the same
methods as manufactured veneer. A mason can
haul and install far more material on an hourly
and daily basis when using thin veneer. A crew
can lay an average of 125 feet of thin veneer
Sustainability
Because it is natural, thin stone veneers
support a broad range of sustainability and
energy-efficiency goals. Natural stone is
highly durable, non-toxic and easy to clean.
Like brick, stone has good thermal mass
defined as a materials ability to store heat
and then slowly release it, thereby keeping
extremes of exterior temperatures from
affecting ambient temperatures indoors.
Natural stone has some of the mass of its fulldimension equivalents and does offer partial
thermal, sound and fire-resistance qualities.
With a life span of more than 1,000 years
when properly designed and built, natural
thin stone veneer provides longevity to
homes and buildings. Unused materials may
be salvaged and used in another structure, or
recycled for such uses as roadway sub-base
materials or permanent landscaping.
Proper installation
Thin stone veneer that is properly adhered
to the substrate will last a lifetime. Generally,
failure of thin stone veneer in the field is the
result of poor installation. It is important to
follow set building codes established for thin
veneer materials, which provide guidelines
for the inclusion of weather-resistant barriers,
metal lath, fastener, and joint information.
The following codes should be consulted:
*2006 International Building Code (IBC)
(Section 1405.9)2006
*International Residential Code (IRC) (Table
R703.4 Note Z)
*2005 Building Code Requirements for
Masonry Structures
*Masonry Standards Joint Committee Code,
ACI-530-05/ASCE 5-05/TMS 402-05 (Sections
6.1 and 6.3) *1999 Standard Building Code
(SBC)
*1997 Uniform Building Code (UBC).
Building codes vary by region, and it is
important to check local building codes,
particularly in areas with frequent seismic
activity.
Installation and design control
Thin stone veneer may be installed right out
of the box, however, many masons prefer
to lie out the product on the ground or
floor to facilitate planning and to ensure an
easier installation and design control. Mortar
color selection will affect the overall product
appearance as will mortar joint dimension or
dry stacking the material, which eliminates the
mortar joint. Selecting a qualified mason is key.
An experienced mason will be skilled at sawing
stones into a coherent design that will ensure
an aesthetically pleasing finished product.
Thin stone veneer may be applied directly over
any clean masonry surface such as concrete
block, brick or cement. The installation process
is the same as synthetic stone, except a
smooth-backed natural stone actually adheres
better than the rough backs of synthetic stone
because manufactured stone can absorb the
moisture out of the mortar prior to curing,
resulting in a weaker bond.
In most exterior applications, a weatherresistant barrier should be used to cover the
wall. However, thin veneer applied to masonry,
stucco or block that is clean and untreated does
not require a weather resistant barrier or metal
lath. According to the Rocky Mountain Masonry
Institute, generally speaking, natural stone
veneer applications are inherently weatherresistant.
In areas that receive constant wetting, including
walls and sills, water-repellent treatments
will help the wall resist moisture penetration
and staining. Dry stacked applications are
not recommended for exterior installation in
climates with freeze/thaw weather cycles, but
may be used for interior installations or warm
climates where it does not freeze. Previously
exposed surfaces that have been stained,
sealed, painted, or treated should be sand
blasted to insure proper mortar bond.
Thin stone veneer products are virtually
maintenance free. All that is generally required
is periodic washing with mild soap or detergent
and a soft brush to remove surface dirt and
dust. Wire brushes should never be used, nor
should acid or acid-based products.
Properly designed and installed, thin stone
veneers provide unique design possibilities to
meet aesthetic and sustainability goals at an
affordable price. There are a wide variety of
styles and colors from which to choose, making
the ability to provide natural, distinctive
solutions to customers an affordable and
beautiful reality.
Article by Jim Hambleton
Masonry Design Magazine
Left: Tuscan Ledgestone - Burnaby, British Columbia