Installing SIPs on a Timber Frame
Structural Insulated Panels (SIPs)
Structural insulated panels (SIPs) are high performance building panels used enclosing the walls and roofs of timber frame homes and commercial structures. The panels are made by installing a core of expanded polystyrene (EPS) insulation between two structural skins of oriented strand board (OSB). SIPs are manufactured under factory controlled conditions and can be custom designed for your needs. The result is a building system that is extremely strong and energy efficient.
Structural Insulated Panels (or SIPS) were first pioneered in the Midwest at the Forest Products Laboratory in Madison, WI; almost immediately Frank Lloyd Wright began using SIPS in some of his Usonian homes. It was a student of Wright’s, Alden Dow (son of the founder of Dow Chemical Company) who created the first foam core in 1952. Since the SIPS have continued to be at the leading edge of home building technology and are now cut in most SIP factories by computer aided machines.
Enclosing your timber frame with SIPs does cost more than enclosing your timber frame using a built up system of dimensional softwood lumber and plywood. However there are several important advantages: it takes 1/3rd the manpower and time on site to enclose the frame, SIP homes are much more energy efficient and tighter buildings than typical built up systems, ceiling finishes such as pre-finished tongue and groove boarding is done at the factory and pre-installed at the factory, window and door openings are pre-cut at the factory, they provide excellent shear walls for timber frames and can span long distances. Several primary disadvantages are the cost, installation of additional HVAC and heat recovery systems, and the absolute necessity for a cold roof, such as lattice work or additional sheathing. Some of these costs are re-cooped when you factor in the labor savings resulting from shorter construction time and less job-site waste, less potential damage to the timber frame due to weather, and the pre-finished and pre-installed ceilings save expensive overhead finishing time later. Other savings are realized because less expensive heating and cooling bills will often be the norm with panelized timber frames as opposed to many built-up wall and roof systems.
It’s a fact, SIP homes go up faster than traditionally framed buildings. Our trained SIP installation crew at Trillium Dell can install the same amount of floor space 2/3rds faster than a stick frame crew. As a huge aid to the process of installation, panels can be manufactured as large as 8- by 24-ft., so entire walls and major roof sections can be put up quickly, reducing the exposure time of your frame to the weather. SIPs are supplied by Trillium Dell as ready to install building components, this eliminates the time needed to perform individual jobsite operations of framing, insulating and sheathing stick-framed walls. We also include electrical chases in the core of panels; these are located at floor outlet height and switch height. Additional chases can be installed as requested by our clients. The structural characteristics of SIPs are similar to that of an I-Beam. The OSB skins act as the flange of the I-beam, while the rigid foam core provides the web. SIPs can be engineered for any timber frame application.
Timber frames enclosed with SIPS are very close to airtight and require mechanical ventilation, unvented SIP enclosure systems will ultimately result in panel failure. These ventilation systems bring fresh air into the building in controlled amounts and exhaust moisture laden and stale air to the outside, proper ventilation is a necessity in all panelized timber frame homes to preserve indoor air quality.
SIPs offer a high tech solution for residential and commercial and public timber frames. Advances in computer aided design and manufacturing allow SIPs to be produced with amazing accuracy . Our SIPs are made with 7/16” oriented strand board (OSB) on both sides, and in some applications 5/8” OSB on one side for steel roof and cement board siding applications. Typical SIPs sizes for timber frame enclosure are 4”- 6” inch walls, and 8”-10” roof panels, depending on climate conditions. The design capabilities, exceptional strength and energy saving insulation make SIPs a great choice for enclosing and supporting timber frames.