FAQ’s

Have a question on structural panels?  Below you will find lots of answers to commonly asked questions.



  • 1.FAQs - Structural Insulated Panels (SIPs)
  • What are Structural Insulated Panels?

    Structural Insulated Panels consist of a layer of foam (Urethane, Expanded Polystyrene or Extruded Polystyrene) sandwiched between oriented strand board (OSB). SIPs make buildings stronger, more durable and more energy efficient than traditional stick-frame construction.

  • Why would I want to build a SIP structure versus a traditional “stick-frame” house?

    Residential and commercial buildings constructed using SIPs are stronger and more energy efficient. They can be built in less time than traditional stick-frame construction with more sustainable materials and very little construction site waste.

  • Are SIPs compatible with other building systems?

    Yes. SIPs are compatible with many other building systems. Panels can be used for floor, on a concrete or timber base, can be used as intermediate floor systems and as roofs. They are seamlessly compatible with stick-framing. SIPs can be used with SIP walls and a conventional truss roof or stick walls and a SIP roof.

  • How long have SIPs been in use?

    SIPS were invented in the 1930’s and throughout the years have been proven to be an effective building method in many applications.

  • What holds the house up since standard framing timber is not used?

    Structural support is provided by the panel skins. SIPs use less timber than conventional framing, and it is optimally placed (as the panel skins), resulting in a wall assembly more than twice as strong as a conventional 100x50 wall. The 1200mm wide panels, up to 7200mm long, are securely held together with plywood “splines” in both wall and roof systems.

  • If I am a builder and I decide to build with SIPs will I save money?

    Yes, Builders can save a substantial amount of money in labour costs because of the speed of construction. Also, SIP construction does not require skilled stick framers and SIPs homes have smaller HVAC requirements.

  • Will homeowners save money if they live in a SIPs home?

    Homeowners will save money on their energy bills and may qualify for energy efficient grants (where applicable). SIPs build homes have a consistent temperature, reducing the need for the use mechanical heating and cooling appliances.

  • What is the interior layout like in a SIPs home?

    Due to the building shell providing a lot of the load-carrying strength of the house, there is an increased flexibility of interior design. Your architect/designer will be able to work with you to maximise the internal layout, in your SIPs construction.

  • Are SIPs strong?

    SIPs are a very strong building material, with the building load being distributed evenly over each panel. Buildings made of SIPs offer exceptional structural strength and flexibility and are being used more frequently in earthquake prone zones.

  • Can I build faster using SIPs?

    Yes, building with SIPs allows the builder to get the building envelope to “dry-in” faster. Our designs allow builders to erect a SIP envelope all in one operation. This envelope includes framing, insulation, electrical chases and exterior sheathing and can be erected in approximately the same amount of time that it would take to only frame the exterior of a traditional stick-frame structure.  By using factory pre-cut panels it is typical for SIP framing to take just a few days rather than weeks needed for stick-built construction.

  • What makes SIPs airtight and why is that important?

    The connections between the panels are typically double-splined together and the interior channel is foamed so there is very little chance for air infiltration. Adhesive is applied to all wood-to-wood connections before they are nailed off. Air infiltration is one of the biggest causes for increased energy use in buildings today. A large portion of a home’s energy loss is through air infiltration. SIP panel construction is far more air tight than stick-frame construction.

  • What skins are used on the panels?

    SIPs panels have an exterior grade of structural oriented strand board (OSB) on both the exterior and interior.

  • How are panels made?

    Urethane panels are made in a continuous lamination process in which the foam is injected between the OSB skins and allowed to expand and bond to the OSB under carefully controlled conditions. EPS and XPS foam cores are bonded to the skins with an adhesive and cured under pressure in a vacuum process.

  • Why is OSB used instead of plywood?

    For a number of reasons. First, OSB is more stable than plywood, particularly in high moisture conditions; de-lamination and linear expansion are much less likely to occur. Second, OSB is available in much longer lengths (up to 7200mm). Third, it is less expensive than plywood, producing a more affordable finished product. Lastly, the fast-growing trees used for OSB are grown in sustainably managed plantation forests.

  • Do I need to add a vapour barrier or use a vapour-retardant paint?

    The panel itself serves as the vapour barrier. Because there are no voids in the panel where moisture could condense, moisture problems are not a concern. Panels will absorb and release some moisture on a seasonal basis, just as the wood in a log cabin does, but there are no harmful effects of this cycling. The only place where moisture migration could conceivably be a concern is at panel joints. Joints between panels are sealed during installation to prevent moisture migration.

  • Do SIPs carry a warranty?

    SIPs supplied and installed by Fenster & Panel has a 20 year warranty covering the structural panels and the panel installation.

  • Are SIPs environmentally responsible?

    Compared to stick-frame construction, SIPs uses much less timber and reduces job site waste, due to being manufactured and cut to size. Much of the off cuts are recycled and reused in the making the future panels. The OSB used in the construction of SIPs is made from wood scraps and fast growth trees grown in sustainably managed forests.

  • Do I need an air-to-air heat exchanger?

    Air-to-air heat exchangers or other types of mechanical ventilation are recommended in all tight houses including those enclosed by SIPs panels. The industry recommends that air-to-air heat exchangers be incorporated into all SIPs homes.

  • Do the major “Green” Building standards recognize SIPs?

    Yes, SIPS are considered very environmentally responsible. Further information can be found in the “Building Green with SIPs” white paper.

  • Who takes care of installing SIPs?

    Fenster & Panel has a team of highly trained SIPs installs who are responsible for the installation of panels. The Fenster & Panel team is available to install SIPs locally and internationally.

  • How long does it take to install a SIPs package?

    The complete panel package, including walls, sub-floors and roof, can usually be installed in one week by our team of installers. With larger houses, or more involved custom designs, installation can take longer.

  • What happens if it rains while the panels are being installed?

    SIPs are not damaged by rain. However, long-term exposure to water will cause the OSB at the cut panel edges to swell.

  • How far along will the structure of the building be when the SIPs installation crew leaves the site?

    The shell will be fully erected and ready for window and door installation, cladding, roofing material, siding and internal framing and finishes.

  • What skills are required for finishing a SIPs home?

    Like with any home, the builder along with a specialist team of carpenters, plasters, painters, electricians, etc are all that you will need to finish a SIPs home.

  • Are windows and doors difficult to install?

    No. Windows and doors are very easy to install in a SIPs home. Units are set into the rough openings (which were built into the shell) and shimmed to level, as per instructions provided by the window and door manufacturers. Then the perimeters are sealed with low-expanding foam sealant, resulting in an extremely energy-efficient installation. Care must be used when foaming around windows and doors so as not to swell the casings.

  • How are interior walls installed?

    Interior partition walls are generally constructed of 100x50s and sheathed with drywall as in conventional frame construction. Where an interior partition wall meets an exterior wall, the edge stud is nailed or screwed into the OSB skin of the panel.

  • How are interior walls installed?

    Interior partition walls are generally constructed of 100x50s and sheathed with drywall as in conventional frame construction. Where an interior partition wall meets an exterior wall, the edge stud is nailed or screwed into the OSB skin of the panel.

  • How are walls finished in a SIPs home?

    Walls are usually finished with drywall on the interior face. On SIPs walls, drywall is installed directly over the OSB surface of panels, applied either vertically or horizontally.

  • How are kitchen cabinets installed?

    Kitchen cabinets are very easy to install in SIPs homes. Along exterior walls, cabinets are screwed directly into the OSB skin of the panels. Because a single layer of OSB is not as thick as a stud, you should use a few more fasteners. Screws are recommended for cabinet attachment. For the strongest attachment, cabinets should be secured directly to the OSB before drywall is installed but it is possible to mount the cabinets to walls after drywall has been installed. On interior (non-SIPs) walls cabinets are installed conventionally by screwing or bolting them into studs.

  • What is the best type of heating system for a SIPs home?

    Any type of heating system can be used. Remember that your SIPs home will maintain a consistent temperature, so only minimal heating required. Talk to your heating contractor or general contractor for recommendations.