insulating celing by the top plate
What is the normal practice for insulating a ceiling where the truss cross the top plate of a wall. There’s only 3.5 ” for the bottom cord of a truss and 3.5 ” for the rafter section. That like 6″ available for insulation where the middle of the truss may have 18″ or more of insulation.
Is there a way to make up for the lack of space to insulate
Replies
A way to prevent that dilemma is to specify "raised heel" or "energy heel" trusses. The roof sits a little higher and you have a slightly larger roof, but it gives you just as much insulation height over the wall as you have over the ceiling.
Edited 2/2/2007 9:44 pm ET by Cornfield
Put your insulation shoots in and try to put some R-19 or thicker as far out on the wall as possible. Then blow insulation right out over the top plate. That way you don't get a cold corner.
We use foam board fit between the trusses to build a baffle to create an air space. If the space is really tight we can use more foam board on the ceiling between the trusses too.
Cut 1" strips place against roof, cut foam board for a close fit. Install against 1" strips toenail in place, gun foam to seal and glue in place. Add blocker at outside edge of wall and seal in place. Add additional foam on ceiling if needed. Insulate with cellulose as usual.