Insulate Hip Roof

If the plastic sheeting is in pieces overlap the pieces by 8 inches and staple it in place directly to the roof rafters and the wall.

Insulate hip roof.

Bare foam board one sided sheathing board or double sided which is also reference as structural insulated panels. Do not use plastic sheeting in this case. Place the plastic sheeting on top of the rolled insulation. The roof overall is 26 x8 and the max height where it meets up with the house is maybe 2 2 1 2 high.

What is the best way to insulate and more importantly ventilate an addition with a hip roof and a very low pitch. That is insulate the bottom of the roof deck with closed cell foam. It s essentially impossible to effectively vent hips. It typically has 3 variations.

Nail 1 furring along every rafter side against the roof deck. Cut and insert 1 or thicker high r foam insulation sheets r 8 per inch against the furring giving a 1 or greater air path between the insulation and the roof deck under the cathedral ceiling. The later is used in new construction as the interior board serves as an inner wall. In a warm roof structure the insulation is placed above or above and between rafters in order to avoid heat loss and energy transfer.

The rafters are 2x8 s. This has the added advantage of bringing any ductwork in the attic into the building envelope and it s becoming an accepted practice. If there is a floor you will need to remove it to properly insulate the roof rafters. Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation.

The right way to insulate attics and cathedral ceilings with batts using certain t. Why do you want to vent the roof. Why not consider a hot roof instead. Originally we insulated with the pink fluffy stuff.

Rigid foam board is just above the roof deck or an exterior insulation option. At hot roof design problems. In the case of a cold roof structure the insulation is placed between or between and under the rafters or at ceiling joist level and the roof is ventilated by leaving a 50mm gap above the insulation which vents air to the outside.