Timberline Panels FAQ
Questions
- What are SIPs?
- How much faster can I build with SIPs?
- How much labor can I save with SIPs?
- How strong are SIPs?
- How do I protect my Timberline SIPs from insects?
- Is there any danger of the SIPs off-gassing?
- Why is OSB used instead of plywood?
- How strong is the Oriented Strand Board (OSB) used in SIPs?
- Does the EPS foam contain formaldehyde?
- What are the building code requirements for panels relative to fire?
- Why should I consider having my order factory pre-cut?
- What does Timberline Panel need from me to get started on an order?
- Where should I send plans and documentation?
- Are there special storage considerations for the panels once they’re on site?
- How do I run electrical in an enclosed panel?
- How do you run plumbing in a Timberline Panel home?
- How ‘green’ are Timberline SIPs?
- How important is ventilation?
- What are the foundation requirements?
- Can Timberline SIPs be modified on site?
- Are Timberline SIPs compatible with other building systems?
- What considerations do you need to take into account when building with SIPs vs. conventional framing?
- Once installed, how long can the SIPs remain exposed to the elements?
- How far along will the shell be when the Timberline crew leaves the site?
- What skills are required for finishing a Timberline Panel Home?
- What kind of roof trim can I use with a Timberline Panel Home?
- Are windows and doors difficult to install?
- How are walls finished in a Timberline Panel Home?
- How are kitchen cabinets and other wall elements mounted to Timberline SIPs?
Answers
What are SIPs?A Structural Insulated Panel (SIP) is monolithic building component produced by a manufacturing process that adheres sheets of 7/16” Oriented Strand Board (OSB) to a core of rigid insulation. The skins and core are bonded together under pressure with a structural adhesive resulting in an exceptionally strong building component with identifiable engineered values and performance characteristics.
Timberline Panel Company (TPC) manufactures SIPs using Expanded Polystyrene (EPS) as the core material. EPS is cost effective, offers excellent insulation values at common wall thicknesses, does not discharge environmentally detrimental gases, and is recyclable.
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How much faster can I build with SIPs?
SIP homes go up faster than traditionally framed buildings. A properly trained SIP installation crew can save a significant amount of time in a build cycle. Timberline Panels can be manufactured as big as 8- by 24-ft., so entire walls can be put up quickly, reducing dry-in time. SIPs can be supplied as ready to install building components when they arrive at the jobsite, eliminating the time needed to perform individual jobsite operations of framing, insulating and sheathing stick-framed walls. Window openings may be precut in the panels, and depending on the size, a separate header may not need to be installed. Electrical chases are typically provided in the core of panels, so there is no need to drill through studs for wiring.
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How much labor can I save with SIPs?
Because SIPs are prefabricated, the amount of additional framing required is minimal. SIPs are always straight and true, there are far fewer callbacks, no culling studs, or need to straighten walls. SIPs also provide a uniform nailing surface for both interior and exterior finishing.
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How strong are SIPs?
The structural characteristics of SIPs are similar to that of a steel I-Beam. The OSB skins act as the flange of the I-beam, while the rigid foam core provides the web. This design gives SIPs an advantage at handling in plane compressive loads. SIPs can be engineered for most applications. Detailed information on the structural performance of SIPs is available from SIPA member manufacturers.
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How do I protect my Timberline SIPs from insects?
No matter what type of home you are building, whether an SIP home or a conventional stick construction home, it is recommended that a regular preventive program of insect treatment be initiated and maintained when building in a known insect risk area. Most pest control companies offer maintenance plans, renewable periodically or annually, and will automatically treat your grounds and structure at pre-determined intervals. With such a program and proper maintenance of the property, you should be able to comfortably minimize the risk of insect infestation.
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Is there any danger of the SIPs off-gassing?
EPS foam does off-gas when it is manufactured; however, it is inert by the time it reaches the Timberline facility before it is manufactured into SIPs. Construction materials of more immediate concern for off-gassing would be pressboard as is found in countertops, underlayment and cabinet backs, and carpeting, for example.
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Why is OSB used instead of plywood?
For a number of reasons. First, OSB is more stable than plywood, particularly in high moisture conditions; delamination and linear expansion are much less likely to occur. Second, OSB is available in much longer lengths (up to 28'). Third, it is less expensive than plywood, producing a more affordable finished product.
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How strong is the Oriented Strand Board (OSB) used in SIPs?
All OSB is not made alike. Saving a few pennies on an inferior raw material can compromise the long term integrity of a home. This is why Timberline uses nothing but premium OSB in all our SIPs. The wood fibers are oriented in a way that gives the board more than adequate strength for satisfactory performance. The strength and integrity of the OSB is fully tested and documented by the manufacturer and other agencies.
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Does the EPS foam contain formaldehyde?
No.
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What are the building code requirements for panels relative to fire?
Building and fire codes vary from place to place. Usually, a 15-minute finish rating is required for light construction. The typical Timberline wall panels, with an interior layer of _" drywall, exceed this requirement substantially. Residential building code requires that foam insulation be separated from the interior of the building by a material that remains in place for at least 15 minutes of fire exposure. Structural insulated panels faced with 0.5” gypsum drywall meet this requirement. Commercial builders may need a one hour fire-rated wall or roof, which is achieved by testing and listing a specific wall or roof assembly to ASTM E119 with an accredited certification agency. Timberline EPS SIPs conform to test standards set by the American Society for Testing and Materials (ASTM E-84) for acceptable flame spread and smoke development for combustible construction materials. ASTM E-84 is a similar test to UL-723, NFPA 2255, or UBC 8-1. There are three classes of acceptability for rigid foam used in construction: Class 3 is unacceptable, Class 2 is the minimum standard required for residential construction, and Class 1 is the best classification available. The EPS cores of Timberline SIPs have a Class 1 Fire Resistance Rating.
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Why should I consider having my order factory pre-cut?
There are several reasons. Timberline Panels uses state-of-the-art precision CNC (Computer Numerical Control) equipment to cut your order accurately. Factory pre-cutting can markedly reduce installation labor, and greatly cut down on site construction scrap, saving disposal costs. Panel Pre-cut drawings are included as part of the Panel Pre-cutting service.
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What does Timberline Panel need from me to get started on an order?
If you require Timberline Panel to configure your order, we’ll need a good set of architectural plans that include dimensions and elevations so we can estimate material quantities and service costs for you.
Builder-specified orders will process more quickly. Here's a list of what you'll need to supply to us:
- Complete final dimensioned drawings, including:
- Four (4) building elevations
- Floor plans - dimensioned
- Building cross-sections - dimensioned
- Complete structural and/or timber frame components - dimensioned
- Roof plan - dimensioned
- Window and door locations
- Window and door schedule listing rough opening sizes (unit dimensions alone are not acceptable)
- Applicable Building Code and design loads (roof, floor, wind, snow, etc.)
Where should I send plans and documentation?
Send your plans and documentation to:
Timberline Panel Company
7 Pearl St
Cambridge, NY 12816
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Are there special storage considerations for the panels once they’re on site?
Timberline SIPs are stacked in bundles and wrapped in heavy gauge plastic prior to shipping. The plastic provides some protection; however, it is recommended that the SIPs be covered with proper protective tarping until ready for use. SIPs should be stored on level risers which elevate the panels high enough off the ground to create an air flow beneath the bundle. This will help inhibit ground moisture from condensing on the underside of the bundle. For extended storage of SIPs, Timberline recommends placing the wrapped panel bundles in a fully enclosed structure that provides protection from exposure to wind, rain, moisture, and UV light. Do not stack bundles more than two high. For more information, refer to the Timberline Panel Installation Manual.
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How do I run electrical in an enclosed panel?
Timberline Panels will supply, upon your request and discretion, horizontal wire chases located through the core of your panel at standard outlet and switch heights. Vertical chases are not made on the edges of the panel, they are cored within the panels. Wire channel cores will allow your electrician to snake wires through these channels and loop from under the floor or in your roof trusses. Our installation manual has more information and helpful tips on electrical wiring using SIPs panels.
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How do you run plumbing in a Timberline Panel home?
There will be almost no differences between plumbing a Timberline Panel home and plumbing a conventional frame house. Plumbing runs should be kept in interior (conventionally framed) partition walls or in specially constructed plumbing chases.
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How ‘green’ are Timberline SIPs?
Timberline SIP buildings are some of the most energy efficient buildings ever developed.
Most of the energy used in homes is for heating and cooling. The exterior shell of the building is critical for energy efficiency and occupant comfort. Timberline SIPs make use of a thick core of Expanded Polystyrene (EPS) which creates both high R-Values (a measure of the resistance to the passage of heat) and low U-Values (a coefficient of heat transfer). Foam construction eliminates the voids and thermal bridges common in conventional stud framing and Fiberglass insulation. In SIP construction the rigid insulation blankets the entire structure in a well-sealed envelope. Less air leakage means fewer drafts, less sound transmission, and a much more comfortable indoor environment. Molds, mildews, and dust are reduced. SIP-enclosed buildings are more fire resistant than stick frame buildings because there are no air cavities in the walls to create the ‘chimney effect’. Air temperature and quality are easily controlled, which drastically reduces energy consumption and thus heating and cooling costs. SIPs have been shown to need 1/100th of an air change per hour to heat or cool outside air to room temperature. Conventional homes often average between one and two air changes per hour. Audits continue to prove that money is saved year after year in these super-insulated, airtight structures. Often energy bills can be reduced by 40% or more by switching to Timberline SIP enclosures.
A home built with Timberline SIPs is kinder to the environment in other ways as well. Using SIPs greatly reduces CO2 emissions over the course of the home’s lifetime. SIPs also reduce construction waste since they can be delivered to the site pre-cut, complete with window and door openings, to exact dimensions. Each panel contains the insulation, structure, and moisture barrier of the wall system. EPS – the insulation – is manufactured without the use or production of CFCs or HCFCs, and it is recyclable. There is no off-gassing issue to be concerned about. Our SIPs utilize Oriented Strand Board (OSB) as the sheathing and facing material that sandwiches the insulation. OSB reduces wood use by as much as 35% and reduces pressure on mature forests by allowing the use of smaller farm-grown trees that can be regenerated in 5-10 years. Exterior grade plywood, for example, requires more mature timber. In so many different respects, building with Timberline SIPs is a far greener method of building than conventional stick framing.
Are there any health risks to building with panels? No. EPS core panels do not contain any formaldehyde, CFCs or other harmful or dangerous gases. In fact, when properly ventilated (through bathroom and kitchen exhaust fans, as well as full air-to-air heat exchanger systems) foam core panel homes are more healthy than conventional homes. Because panel homes are so tight, it is relatively easy and economical to maintain healthy temperature and humidity levels. It is possible to have a home that is too tight, however, so some attention should be paid to factors such as sources of moisture and indoor pollutants when designing the home's mechanical systems.
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How important is ventilation?
We recommend and strongly encourage the installation of a Heat Recovery Ventilation (HRV) system in your home. Since a Timberline Panel building is extremely airtight, mechanical ventilation is required.
Ventilation systems bring fresh air into the building in controlled amounts and exhaust moisture laden and stale air to the outside. By limiting air exchange to controlled ventilation systems, all incoming air will be filtered for allergens and dehumidified with significantly improved air quality as a result. Additionally, proper ventilation is important for maintaining appropriate indoor humidity levels and optimum building performance.
Can I use smaller HVAC equipment since my Timberline Panel home is so airtight?
The high insulating properties of a Timberline SIP enclosed building also enables the installation of smaller HVAC equipment than other building types. When working with an HVAC contractor, make sure their calculations take into account an accurate estimation of typically low levels of air infiltration in a SIP enclosed home. 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.
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What are the foundation requirements?
The buyer is responsible for having the foundation installed to the specifications provided by Timberline Panels. A Timberline Panel Home can be built on a slab-on-grade foundation, or on frost walls over a full basement or crawl space. It is extremely important that the foundation is built to close tolerances. Because of the accuracy of the supplied components, even slight inaccuracies in foundation level and squareness can result in problems with shell erection.
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Can Timberline SIPs be modified on site?
On-site modification can easily be done using a few additional SIP specific 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 specialized angle grinder attachment to recess the core.
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Are Timberline SIPs compatible with other building systems?
Timberline SIPs are compatible with other building systems. Wall panels can sit on a variety of foundation materials, including poured concrete, blocks, or insulated concrete forms. SIPs are sized to accept dimensional lumber and are seamlessly compatible with stick framing. Builders may choose to build with SIP walls and a conventional truss roof, or stick walls and a SIP roof with little difficulty. SIPs are also popular as a method of providing a well-insulated building envelope for timber frame structures.
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What considerations do you need to take into account when building with SIPs vs. conventional framing?
The majority of construction with Timberline SIPs is very similar to conventional framing. SIPs accept dimensional lumber and are fastened together using staples, nails or screws. Proper sealing is especially crucial in a SIP structure. All joints need to be sealed with specially designed SIP sealing mastic or low expanding foam sealant, and/or SIP tape. Voids between panels and unused electrical chases need to be filled with low expanding foam. In addition to sealing, planning and consideration needs to be applied to material handling. Although smaller 8- by 4-ft. panels can be set by hand, larger 8- by 24-ft. panels require the use of equipment to unload and set.
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Once installed, how long can the SIPs remain exposed to the elements?
Timberline SIPs should be completely covered as quickly as possible upon installation with code approved weatherproof roofing, siding, and trim to prevent exposure of the OSB to the elements and to UV rays.
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How far along will the shell be when the Timberline crew leaves the site?
The shell will be fully erected and ready for window and door installation, roofing, siding and interior finish.
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What skills are required for finishing a Timberline Panel Home?
General carpentry skills are all that you will need to finish a Timberline Panel Home. Skilled homeowners can do most of the work themselves, subcontracting out work requiring specialized skills, such as electrical and plumbing work.
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What kind of roof trim can I use with a Timberline Panel Home?
The outer roof edge, both along eaves and gable ends, will have two-by splines installed. You can add any trim to this you wish, to meet your design preferences. At the eaves, some people choose full-return horizontal soffits with ornate fascia trim, while others choose simple sloped soffits, nailed directly to the panel overhang.
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Are windows and doors difficult to install?
No. Windows and doors are very easy to install in a Timberline Panel 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 window frame.
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How are walls finished in a Timberline Panel Home?
Walls are usually finished with drywall on the interior face. On the SIP walls, drywall is installed directly over the OSB surface of panels, applied either vertically or horizontally. Some builders use construction adhesive in applying drywall to the panels, enabling them to use fewer fasteners. On interior partition walls (which are framed conventionally), drywalling is done in a standard manner, nailing or screwing drywall to the studs. With cathedral ceilings, some builders prefer to substitute tongue-and-groove clad panels, which can have an interior facing of various wood species. The wood facing provides the required fire rating and offers the beauty of a natural wood. For information on T&G clad panels, contact Timberline Panels.
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How are kitchen cabinets and other wall elements mounted to Timberline SIPs?
Standard installation procedure of screwing the cabinets to the walls is usually acceptable, although you may want to use a few more screws. Excessively heavy items may require readily available specialty fasteners.
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