Archaeologists point to wood branches as some of the first framing materials. This could include bamboo in other parts of the world but the wood-type frame has been around since man first sought shelter from the elements. This would be tied together with vines or sinews and then sheathing would be attached - broad leaves, tree boughs or grasses - to shed water and protect the occupants.

In today's construction wood framing is still one of the most popular structural components of a home. Compared to other materials like cement block and concrete wood is still relatively inexpensive and readily available in most parts of North America. If shielded properly from the elements and kept dry there is no reason wood frames should not last hundreds of years. In fact there are wood-framed homes built in the early 1700's that are still standing with the original framework.

To accommodate insulation in wood framed the studs are usually 16" apart. Fiberglass batts or foam insulation is usually applied and then partitioned from the interior walls with a plastic vapor seal to prevent moisture from inside the home from getting into the insulation. The problem with fiberglass batts is that, if not installed properly, air can get in from outside and enter the home through electrical outlets and fixtures.

Structural Insulated Panels

The desire for a different way of framing a home led designers to the idea of stressed-skinned panels. This was based on an idea that the boards themselves could handle the stress of a building. But the walls were heavy and cranes were needed to put them into place.

In the 1970's foam-core panels began getting recognition in building circles. These are called structural insulated panels (SIP) and are basically a thick foam sheet sandwiched by two structural boards made from oriented strand board or plywood. Each panel size is up to 8' x 24' with thicknesses to 11 1/4 inch. In recent times SIPs have grown considerably as a building material of choice, especially in areas of extreme weather where their insulating qualities make a difference on energy savings.

In essence, SIPs become the whole house. They take the place of wall studs, insulation, vapor seal and exterior skin of the home. Siding and interior drywall are applied right to the surfaces which are engineered to be perfectly plumb. That means there is no guess work on where to put screws and the walls go on perfectly every time. This saves for drywalling crews. In addition, SIPs can be ordered from the plant in the right sizes for the building project so that there is little wastage.

Building with Structural Insulated Panels

After the main flooring is built on the foundation a 2" X 6" starter strip is nailed along the edges leaving a 3/4" space around the perimeter. The SIP panel has a hollow bottom (free of foam) which allows the panel to fit over top of this starter strip. Starting at the corner two SIPs are put in at the same time so that they can anchor against each other. Two more 2" X 6" studs are slid in on top and nailed together, overlapping each for greater strength. Now the tops and bottoms of the 2 panels are screwed into the studs making for strong corner. Now this corner can act as an anchor for the rest of the walls. Sips can be manufactured to form the gable ends of the home, reaching from the floor to a peak up to 24' high. Roofs are also SIPs. A beam is run from each of the gable ends and the SIP ends are cut at an angle to meet at the peak.

Advantages of Structural Insulated Panels

1. Homes built with SIP framing are from 50-75% more efficient than stick-built homes.

2. HVAC system is 50-75% smaller than non-SIP homes.

3. Cuts overall construction time by an average of 2-4 weeks.

4. Trim and cabinet installation easier because of the straight walls.

5. Factory precut panels cuts down on wastage.

6. Weather-tight and security-locked within days cutting down on thefts from the site.

7. SIP roofs are stronger than framed roofs.

Installing structural insulated panels is not a do-it-yourself job. Skilled contractors and crews are required to perform the many tasks needed for a quick and efficient job.