Frequently asked questions

Q: What type of buildings can be constructed from SIP’s panels?

A: The application of SIP’s is limited only by the imagination of the designer or architect. SIP’s have been used to build affordable housing, luxury mega-homes, churches, factories, warehouses, retail stores and office buildings. SIP’s are also well suited for refrigerated spaces as well as rooms or buildings with special sound attenuation requirements.

Q: What changes in the construction of the building envelope should be taken into account when comparing SIP’s to conventional stud framing?

A: The majority of construction with SIP’s is very similar to conventional stud framing. SIP’s can be joined to the dimensional lumber of the interior framing with staples, nails or screws. Proper sealing is a critical step in the SIP building process; all joints should be sealed with specially designed SIP sealing mastic, low expanding foam sealant, and/or SIP tape. Voids between panels and unused electrical chases should to be filled with low expanding foam. In addition to sealing, there are logistical issues related to the handling of panels that must be considered. While smaller 8 by 4 foot panels can be manipulated by hand, larger panels require the use of equipment to unload and set in place.

Q: When should the decision be made whether or not to build with SIP’s?

A: Most home plans can be adapted for SIP’s construction, but if the plan was not designed with SIP’s specifically in mind, there can be considerable waste in the manufacturing process. In larger plans the incremental cost may not be important, but with smaller homes where the budget is often tight, this can be very important.

Q: Do I need to use panels for both the walls and the roof?

A: A building envelope constructed entirely of SIP’s will result in a more airtight, energy efficient building. However, wind loss through stud framed exterior walls can account for a substantial portion of the heat loss or gain in a building; if the design does not lend itself to a complete SIP envelope, SIP walls in combination with another roofing system can still be a tremendous energy saver.

Q: Can panels be modified on-site?

A: On-site modification can easily be done with the proper tools. Panels can be cut using a beam saw or a beam cutting attachment to a circular saw. The foam core can then be recessed for splines or dimensional lumber using a hot wire foam scoop or a specialized angle grinder attachment to recess the core.

Q: How are windows and doors installed in a SIP building?

Openings for windows and doors are precut in the factory to accommodate the specific dimensions of the windows and doors. Boundary framing is then installed and the window or door is conventionally set.

Q: How are electrical wiring and fixtures installed?

A: Electrical wires are pulled through precut channels or “chases” inside the panel’s EPS foam core. RABS cuts the chases into the panels in the factory in accordance with the architectural plans of the building. Once erected on-site, the electricians then fish the wires through the panel’s pre-cut chases.

Q: How do I properly size HVAC equipment?

A: SIP’s allow for the specification of smaller HVAC systems. When working with your HVAC contractor it is vital to ensure that their calculations take into account the airtight character of a SIP home. Proper HVAC sizing is crucial, as an oversized HVAC system will fail to perform at the operating frequency that the equipment was designed for. Short cycling HVAC equipment is less energy efficient and requires more frequent maintenance than properly sized systems. Typically, tonnage requirements for AC are approximately 50% less in a SIP home vs. a stud framed home.

Q: How important is ventilation?

A: Proper ventilation is vital to the air quality of any enclosed space. SIP buildings are extremely airtight and require mechanical ventilation to control the intake of fresh air and to expel moisture laden and stale air. The airtight character of a SIP building envelope prevents the flow of air into the interior except as is called for by the ventilation system, enabling the air to be filtered for allergens, dust, pollens and other airborne particles. Humidity can also be controlled by the ventilation system, resulting in a more conditioned and comfortable indoor environment for occupants while reducing susceptibility to mold growth and dust mites. Traditionally built stud framed structures are extremely vulnerable to the infiltration of untreated air are unable to match the air quality of a SIP building.

Q: How does a SIP’s envelope improve indoor air quality?

A: The air tight character of a SIP building envelope prevents the flow of air into the interior except as is called for in a controlled manner, reducing the infiltration of dust, pollens and other airborne particles. Humidity is also controlled more easily, resulting in a more comfortable indoor environment while reducing susceptibility to mold growth and dust mites. The air tightness of a SIP built home has been recognized by American Lung Association as meeting the requirements of their air quality controlled home.

Q: Should an attic beneath a SIP roof be ventilated?

A: No. All of the area inside a SIP building envelope is conditioned space and is ventilated by the building’s HVAC system. Venting an attic beneath a SIP roof is not recommended as it compromises the airtight nature of the building.

Q: Why do SIP built structures outperform stud framed buildings with the same R-Value factor?

A: R-Value factors tell only a portion story relating to the thermal properties of a given building material or structure. R-Value ratings measure the resistance to heat loss that is attributable to conduction. This measurement was not intended to rate the thermal efficiency of a particular material or wall assembly, as other forms of energy loss besides conduction can come into play, namely convection, radiation and infiltration (leakage). For instance, approximately 40% of the energy loss of a conventional stud framed structure with batt insulation is lost to air leakage/infiltration; in contrast, a properly constructed SIP building experiences virtually no air leakage.

Q: Are SIP’s vulnerable to termite infestation?

A: As is the case with any structure that is build all or in part with wood, proper termite prevention measures are highly recommended for SIP buildings.

Q. What type of exterior finishes are compatible with SIP’s?

A: All types of siding and cladding materials can be employed in conjunction with SIP’s. The OSB wood face of the panels provides an excellent surface for screws and nails and eliminates the need to search for studs.

Q. What type of roofing products are compatible with SIP’s?

A: Roofs made of SIP’s can accommodate almost all roofing products available in the housing market today. The OSB used to manufacture SIP’s is the same product that is used for roof decking in stud framing, except that the board used for SIP’s is a higher density board with more fiber content. Most roofing manufacturers specify how to attach their product to SIP’s. Please contact the roofing manufacturer for the appropriate application instructions. One caution: a few asphalt shingle manufacturers will not warranty their shingles if they are applied over SIP panels, so verify warranty coverage prior to installation.