By early August the trusses were complete and Green Hammer installed the structural insulated panels (SIP’s) which make up our roof structure.  SIP’s are composed of 8” thick rigid polystyrene foam insulation sandwiched in between two sheets of oriented strand board (OSB).  The SIP’s are manufactured in a warehouse, individually numbered and delivered in the order they are to be assembled. The panels were hoisted into place by a boom truck and are attached to the trusses by 400 metal L-brackets.  We elected to keep the OSB exposed to reduce cost and materials so the SIP’s were stained with Timber Pro UV wood preservative.  Timber Pro is a low volatile organic compound (VOC) stain which protects wood from UV light and moisture damage.

After the SIP’s were in place Willamette Roofing installed a slate grey, standing seam metal roof.  While there are many excellent choices for sustainable roof systems, we decided on a metal roof because of its longevity and minimal maintenance requirements.  In addition, metal is recyclable and is also a good foundation for solar hot water and photo voltaic panels.