WPS:FAQ
What are WPS?
WALLPANEL SYSTEMS Structural insulated panels (WPS) are high performance building
panels used in floors, walls, and roofs for residential and light commercial buildings. The
panels are made of highly dense composite(EPS) and structural steel studs. WPS are
manufactured under factory controlled conditions and can be used to build any design
without the need for entire wall sections to be pre-built by the factory, thus further reducing cost of manufacturing. The result is a building system that is extremely strong, energy
efficient and cost effective. Building with WPS will save you time, money and labor.
How much faster can I build with WPS?
WPS homes go up much faster than traditionally framed buildings, usually 80% faster with a trained crew. Even without training, WPS installation can cut framing time in half compared to conventional wood framing, and the total build by a greater amount. Panels are manufactured in different sizes and density to suit different needs. Walls and roof sections can be built quickly. WPS are ready to install when they arrive at the jobsite, eliminating the time needed to perform the individual jobsite operations of framing, insulating and sheathing stick-framed walls. Electrical channels are preinstalled in the core of panels, so there is no need to drill through studs for wiring.
How much money can I save with WPS?
Builders can save money through decreased construction and labor costs. A high
performance building envelope often allows HVAC equipment to be downsized and
ductwork to be minimized. Builders can all but eliminate jobsite waste disposal.
Homeowners that incorporate other energy-efficient features into a WPS home can see
utility savings of 70 percent or more
How green are WPS?
Structural insulated panels are one of the most environmentally responsible building
systems available. A WPS building envelope provides continuous insulation, and allows for
better control of indoor air quality, reduces construction waste, and helps save natural
resources. Life cycle analysis has shown that WPS homes have a tremendous positive
environmental impact by reducing energy use and greenhouse gas emissions throughout the home’s life cycle.
How strong are WPS?
The structural characteristics of WPS are significantly stronger than standard SIPs, wood
frame or brick and mortar construction. Rack and sheer testing has shown the WPS
structural strength better than 13,000 lbs/in, enough to survive Mother Nature’s worst
storms and hurricanes.
How do I properly size HVAC equipment?
A high performance WPS building enclosure often allows smaller HVAC equipment to be
specified. It is important to work with a qualified HVAC professional that can accurately
estimate the low levels of air infiltration in a WPS home or commercial building. Proper
HVAC sizing is crucial because an oversized HVAC system will fail to reach the steady
operating rate the equipment was designed for. Short cycling HVAC equipment will be less
energy efficient and require more maintenance than properly sized HVAC equipment.
How important is ventilation?
While SIPs buildings are extremely airtight and require mechanical ventilation. WPS does
not require ventilation systems to bring fresh air into the (home?) to exhaust moisture laden and
stale air to the outside, which is one of the downsides of other SIPs.
How do WPS improve indoor air quality?
A controlled indoor environment is both healthy and comfortable. Humidity can be
controlled more easily in a WPS home, resulting in a home that is more comfortable for
occupants and less prone to mold growth and dust mites.
How do WPS react to Fire?
When paired with the fire and flame-retardant MULTICERAMICS, WPS present a very
minimal fire risk when their construction meets the fire precautions listed in the building
code. Residential codes typically require the application of a 15-minute fire-resistant thermal barrier on the interior for all residential structures, accomplished by applying 1/2-
in. thick gypsum board or a material of equivalent thermal performance. Light commercial or multi-use buildings of Type V Fire Rated construction often require a one-hour fire rating and/or sprinkler systems. Many WPS manufacturers can provide tested assemblies for both walls and roofs that meet the one-hour fire resistance tests outlined in ASTM E 119.
Are WPS compatible with other building systems?
WPS are compatible with all building systems. Wall panels can sit on a variety of
foundation materials, including poured concrete, blocks, or insulated concrete forms. WPS
are sized to accept dimensional lumber and are seamlessly compatible with stick framing.
Builders may choose to build with WPS walls and a conventional truss roof, or stick walls
and a WPS roof with little difficulty. WPS are also popular as a method of providing a well insulated building enclosure for timber frame structures.
What considerations do you need to take into account when building with WPSvs. conventional framing?
The WPS is much easier and faster than conventional framing. WPS accept dimensional
lumber and are fastened together using self tapping screws, unlike SIPs WPS panels do not
require the use of equipment to unload and set.
Can WPS be modified on site?
On-site modification can easily be done at any time and no special tools are needed.
How are electrical wiring and fixtures installed?
Electrical wires are pulled through precut channels inside the core of the panels called
“chases.” Chases are added during the manufacturing process according to the electrical
design of the home. Electricians can feed wires through panel chases without compressing
the insulation or drilling through studs.
Are WPS susceptible to insects?
Termites and other pests do not feed on the foam panel cores.
Can WPS be replaced or repaired if damaged?
If panels are damaged, a structural engineer needs to assess the damage to determine what is cosmetic and what is structural. If the damage is only cosmetic, then the source must be determined and fixed, whether it is from inside or outside. If the damage is structural, then a structural solution to the problem must be found. That can be done by either a site modification of the panels or replacement of the panels, depending on the extent of the damage. In the event that panels are damaged, the manufacturer and installer of the panels should be notified.
Does a building with a WPS roof need to be ventilated?
The area inside a WPS building envelope is considered conditioned space and will be
ventilated by the building’s HVAC system. There is no need to provide a vented attic
beneath a WPS roof, and doing so would compromise the conditioned space of the building.
Research conducted by Building Science Corporation on test homes in hot climates
demonstrates that including the attic in the conditioned space allowed for more energy efficient space conditioning and less probability of moisture related issues. Some building science experts recommend venting the roof by providing an air spacebetween the WPS roof panels and the roofing material (known as a “cold roof”). This practice is not a requirement for WPS buildings, but an extra measure to improve the durability and moisture resistance of the building
.
How much do WPS cost?
Pricing information can be obtained by contacting our office. Material price does not reflect
the labor savings capable with WPS construction. A study conducted by the R.S. Means shows that building with WPS reduce framing labor over conventional wood framing. Builders can also expect decreased jobsite waste disposal costs and savings on HVAC equipment. When all these factors are considered, building with WPS is by far less expensive than other building systems.
Are WPS accepted by building codes?
WPS construction is recognized by the International Code Council body of building codes,
which are used by most jurisdictions in the U.S. for residential building. Specific construction practices for WPS wall systems are included in Section R614 of the 2009 International Residential Code. For applications beyond the scope of Section R614, the building inspector will typically require a licensed engineer or architect to approve the building plans prior to construction. An engineer’s approval is always required in high wind areas, high seismic zones and commercial buildings.
How do I attach siding or other exterior claddings to WPS?
Builders should consult the siding manufacturer’s installation instructions for how to attach
their product to WPS. Because WPS use no lumber, an increased fastening schedule is often required when attaching exterior cladding. If the siding manufacturer does not offer recommendations for attaching their product to WPS, a licensed architect or engineer can calculate the appropriate fastener frequency by obtaining fastener pullout capacities from the WPS manufacturer. It is also important that proper moisture management procedures be followed when applying any type of cladding to WPS. With the exception of metal and vinyl siding, it is recommended that all claddings be installed with a drainage gap between the cladding and the weather resistant barrier in climates that average more than 20 inches of annual rainfall.
What is the R-value of WPS?
R-values for WPS depend on the thickness and density of the WPS. WPS R-values range
from R16 for a standard 4’ X 4’ X 8’ panel (#1.5 foam density - without MULTICERAMICS
insulated coating) to R60 for the SUPERTHERMAL 4’ X 6’ X 8’ panel (2# foam density –
with MULTICERAMICS insulated coating).
How are WPS supported? Are there studs in the panels?
WPS are structurally supported by steel beam studs placed at 16” intervals on center. The
unique, patented design of the studs is the primary characteristic that gives the WPS their
super strength.
Can recessed lights be used in WPS?
Recessed lights should never be embedded in structural insulated panels. To install
recessed lights, an interior soffit must be constructed.
Do WPS block sound transmission?
The WPS are especially effective at blocking high frequency noise and most homeowners
notice the quiet comfort of a WPS home.
Are vapor barriers required in WPS buildings?
Air barriers or vapor barriers are not required in WPS buildings because properly sealed
WPS create a code compliant air barrier with a permeability rating of less than 1.0 perm. In addition, the foam core of WPS is solid and continuous throughout the wall, eliminating the
convection and condensation issues that can occur in cavity walls.
Can plumbing be installed in WPS?
Plumbing should not be located in exterior WPS walls because of the possibility of
condensation or supply lines freezing in cold climates. During the design phase of the
project, all plumbing should be relocated to interior walls.If plumbing must be located on an exterior wall, it is recommended that all plumbing beinsulated using our PIPESULATE coating. Plumbing penetrations such as DWV can beplaced through WPS if they are thoroughly sealed to prevent air infiltration.
Can kitchen cabinets be attached to WPS?
Yes, when self tapping screws are used with the 18 gauge steel studs, it will offer a much
stronger pull out resistance than the OSB used in conventional SIPs. A licensed architect or
engineer can calculate the appropriate fastener frequency by obtaining fastener pullout
capacities from WPS.
Are WPS susceptible to mold and mildew?
WPS building envelope forms the basis of a successful mold control strategy. The extremely low levels of air infiltration in WPS buildings allow for incoming air to be provided in controlled amounts by air handling equipment. Proper dehumidification of incoming air
following ASHRAE standards will create an environment where mold physically cannot
grow. In addition to creating a comfortable structure, WPS are solid and free of any cavities
in the wall where moisture can condense and cause unseen mold growth, all metal surfaces
should be coated with MULTICERAMICS insulation coating to further prevent
condensation.
I want to build a WPS home. What is the first step?
For homeowners, the first step is to identify a quality builder. An experienced WPS builder
will manage the plan conversion and review process. If your builder is unfamiliar with
WPS, they can contact us with any questions they may have.
How does the WPS design and fabrication process work?
The construction of a WPS home or commercial building begins with the construction
documents. Once the construction documents are in the hands of a WPS manufacturer,
dealer/distributor, or design professional, then the number of panels needed for the construction are calculated by our engineering department and a formal quote for all
necessary components is given.
How difficult is it to learn how to build with WPS?
For construction professionals competent in standard wood framing techniques, the task of
learning WPS is not difficult. WPS offers technical assistance for builders that are new to
WPS construction