Tech Brief 15
Fiber Cement Siding
Fiber cement siding offers the appearance of traditional
wood-based siding materials with much lower maintenance requirements,
while maintaining its shape and color much better than
vinyl siding. About 12 % to 15 % of all new homes are now clad with fiber cement siding.
What is fiber cement siding?
Fiber cement siding is produced from a mixture of cement, sand, and
cellulosic fibers. Manufacturing of fiber cement siding
utilizes autoclaving, a high temperature steam curing process,
to increase strength and dimensional stability. The cellulosic
fibers are added to the mixture to prevent cracking.
Fiber cement siding is manufactured in layers forming a sheet
of the desired thickness. A wood grain is imprinted
onto the surface at the time the uncured product is lifted
by an accumulator roll and cut into individual sections, or in a separate
high pressure molding process immediately after the product is cut.
Several design options, and a full palette of colors, are available
with fiber cement siding. One option is horizontal
lap siding, which includes profiles such as: Dutch, beaded,
and traditional. You may want to incorporate architectural
elements adding personality to your home. Shaped fiber cement siding is available as shingles, half rounds, octagons,
and random squares (with either a
straight or staggered edge). Vertical siding options include
a traditional stucco appearance, smooth or cedar
(either without vertical grooves or with regular interval grooves.)
Fiber cement soffits are also available in smooth
and cedar textures, both of which can be vented. Matching low maintenance composite trim materials can complete the architectural design.
What are the advantages of fiber cement siding?
Fiber cement siding provides a traditional wood grain appearance
without the drawbacks associated with wood. It’s available
in a variety of textures, profiles, and colors matching your
design requirements. Fiber cement manufacturers offer
complete systems for siding, decorative shapes, soffit
and trim applications. This remarkable product is manufactured
under rigorous factory specifications and guidelines, providing
consistent quality and excellent dimensional stability. It doesn’t warp,
buckle, or fade—traits associated with vinyl siding products—and
holds a Class 1 (A) Fire Rating. Fiber cement siding will
not rot, is capable of withstanding damaging effects of salt
spray and ultraviolet rays, and cannot be penetrated by
birds or insects. Once installed, the product stands up
to bumps and direct impacts, unlike aluminum siding, and doesn’t
become brittle in freezing conditions or melt in the presence
of heat sources, like barbeque grills, as does vinyl siding.
Fiber cement products can be used in historic preservation areas
where other cladding materials are forbidden. Fiber cement
siding holds paint well, with some products warranted to hold
paint for up to twenty-five years. Transferable product warranties
can last as long as fifty years depending on the degree of “pre-finish” applied in the
Photos courtesy of CertainTeed Corporation
> Return to top
What options do I have in selecting fiber cement siding?
Most people buy fiber cement siding that has been factory primed and sealed
or is fully prefinished in the factory. Factory priming protects
the product from moisture penetration on the job site and once
the product is installed. Some contractors choose to buy the product
raw and then prime and finish paint it themselves, although
this is not recommended by manufacturers and may affect the warranty.
How much does fiber cement siding cost?
There are three factors affecting the overall cost of the siding product
you select: the cost of materials, labor and paint or stain being
applied. Of particular interest is comparing the total in-place,
system price (including paint or stain) to other cladding systems.
Fiber cement costs about 75% less than natural stone, 37% less
than cedar, 24% less than wood siding and slightly more than hardboard siding
to install and finish on a new home, according to R.S. Means data (see chart).
> Return to top
How difficult is fiber cement
siding to maintain?
While fiber cement siding is a low maintenance product, it does require
some care to maintain its appearance. Insect nests and
accumulated dirt can easily be removed by power washing. It’s also
a good idea to inspect caulked joints each year between butt ends of boards,
windows, and doors. Gaps that open when caulk pulls
easily be filled with a high quality acrylic, latex, or urethane
caulk meeting ASTM Standard C-920 and are readily available
in hardware and paint stores. A well maintained
fiber cement siding product generally requires repainting only
every seven to fifteen years.
What should I look for to be sure I'm getting a
quality siding job?
The first step is locating a builder or siding contractor with experience
installing fiber cement siding. Ask for references and look
at jobs your contractor has completed to verify you will get a quality installation.
Are the joints neat and evenly caulked? Fiber cement product installations
not suited for do-it-yourself projects. Special tools and expertise
are required to install the product.
Once you select a contractor, discuss whether you want to choose
from the palette of colors offered by
the manufacturer or prefer to buy a pre-primed product that will
be finish painted or stained to the
color of your choice following installation.
> Return to top
What's the bottom line?
Fiber cement siding costs 24% less on an installed basis than wood siding
and is significantly less expensive than natural stone siding.
It is more durable than wood, vinyl, and aluminum, while
matching the appearance of traditional wood without costly maintenance
and repair hassles.
For More Information
To learn more about fiber cement siding, installation practices,
and warranties visit:
Cemplank - www.cemplank.com
CertainTeed Corporation - www.certainteed.com
GAF Materials - www.gaf.com
James Hardie - www.jameshardie.com
MaxiTile - www.maxitile.com
Nichiha USA - www.nichiha.com
Concrete Homes Helpline: (888) 333-4840
> Return to top