Insulate Hip Roof

The rafters are 2x8 s.

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. 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. Originally we insulated with the pink fluffy stuff. In a warm roof structure the insulation is placed above or above and between rafters in order to avoid heat loss and energy transfer.

Do not use plastic sheeting in this case. To get the most r value with the least thickness use batt insulation with higher r value per inch in combination with rigid foam insulation. This has the added advantage of bringing any ductwork in the attic into the building envelope and it s becoming an accepted practice. Why do you want to vent the roof.

Why not consider a hot roof instead. Nail 1 furring along every rafter side against the roof deck. It s essentially impossible to effectively vent hips. What is the best way to insulate and more importantly ventilate an addition with a hip roof and a very low pitch.

Hitting amazing levels of 0 13w m will need 300mm of mineral wool or 180mm of rigid foam. If there is a floor you will need to remove it to properly insulate the roof rafters. The roof overall is 26 x8 and the max height where it meets up with the house is maybe 2 2 1 2 high. The right way to insulate attics and cathedral ceilings with batts using certain t.

At hot roof design problems. The later is used in new construction as the interior board serves as an inner wall. Bare foam board one sided sheathing board or double sided which is also reference as structural insulated panels. 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.

Rigid foam board is just above the roof deck or an exterior insulation option. 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. Place the plastic sheeting on top of the rolled insulation.