Roof Rafter Insulation Ventilation

Also you must have adequate ventilation along both the lower and upper edge of the roof and continuous venting channels in every rafter bay.

Roof rafter insulation ventilation.

The idea is to allow some air to circulate through some part of the attic under the roof but outside the insulation to prevent moisture build up. The fresh air flows up between rafters to the ridge where a ridge vent roof vents or gable vents allow the air to exit. Soffit vents are the small metal or plastic grates you probably have seen under the eaves of houses. Owens corning raft r mate 22 1 2 in.

The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow. Once the purlins are in place the new rafters are installed followed by the proper installation of the insulation to avoid air movement and thermal bridging. An attic with balanced ventilation has undereave or soffit vents which allow fresh air into the attic. Leave enough clear space above the insulation and above the new roof rafter to allow for ventilation.

Rafter vents come in 4 foot lengths and 14 1 2 and 22 1 2 inch widths for different rafter spacings. If you really don t want a finished ceiling below but you do want some insulation i would using foil faced polyisocyanurate foam iso board such as r max or thermax. Set your store to see local. Item 1571672 model xudv2248.

To install the rafter vents staple them directly to the roof decking. If you have vents in the walls of the attic or in the roof ridge then the insulation can go all the way to the roof. Save 17 90 10 161 10. Attach this roof and attic insulation treatment using foam baffles to ventilate insulate and channel cold and hot air to roof vents before insulation is add.

If insulation is allowed to bunch against the inside slope of the roof between the rafters air will be blocked before. Durovent durovent 22 in x48 in raft vent 10 pack. Save 17 90 10 standard delivery. You only need those if you have vents in the soffits under the eaves.

Covering up the soffit vents with loose fill or batts which can happen if you stuff insulation along the eaves is a huge no no. Attic insulation rafter baffle proper vents 70 pieces model 70rm view the owens corning attic insulation 161 10. Rafter vents ensure the soffit vents are clear and there is a channel for outside air to move into the attic at the soffits and out through the gable or ridge vent.