Tuesday, March 9, 2010
built green - insulation
Many of the points we received for Built Green are for items not seen now that the house is finished. One of the big things that makes this house energy efficient and comfortable is the extra insulation we used as well as the air sealing. We used BIBS (Blown-In-Blanket-System) which is much more effective than push-in batt insulation in the walls and provides for a higher level of insulation (R23). It is far superior to batt in the walls because it fills in all around the electrical wiring and plumbing pipes. "Tests show that a mere 4% void area from a poorly installed batt causes a 50% increase in heat loss. The Blow-In-Blanket® System eliminates voids and does not settle." It also provides better sound control. Looking at this picture you can see how Neil used some advanced framing techniques. Simple things like insulated headers and ladder framing at interior to exterior wall intersections, increases the insulation area of the wall. The blocking to the right of the window is for the convection heater and there is insulation behind it. Also if you look closely you will see caulking along the plates and wood intersections. This seals the wall cavity from air leaks from the exterior to the interior of the house and is one reason we did so well on our blower door test.
We used scissor trusses for the roof structure and because of this had extra depth to increase the roof insulation up to R-49. Here we used EcoBatts. Since the cavities were not filled with mechanical items like the walls, it was fairly straight forward to use Batts. We had Chris of the O'Brien Company out to inspect before we put the gypsum wallboard.