Insulating A Roof Without Felt

The roof can usually be insulated under the rafters with sheet insulation and incorporate a vapour barrier.

Insulating a roof without felt.

Loft insulation against rafters on an old roof with no felt lining under the tiles i want to make more use of the loft space and ideally want to insulate and board up the roof to create an clean insulated space. If the roof is nailsick the slates should be removed with a proper slate ripper and checked for cracks and kept for reuse. Depending on your climate you ll need r 30 to r 49 to meet code which is 5 to 8 1 2 inches of polyiso rigid foam which is r 6 per inch. Add a preinstalled membrane to absorb and release the condensation as it forms with the natural weather cycle.

I would lean toward adding rigid foam either on top of the roof or on the inside under the joists if reducing headroom isn t a problem. When the home inspector checked the roof he found that the new shingles were installed without a layer of felt. He also found a water stain on the living room ceiling and recommended that the. Roofing felt was introduced primarily to act as a secondary barrier against wind driven snow and rain but its use also causes a reduction in air movement within the roof space particularly if the roofing felt is impervious and this effect is often compounded by the introduction of insulation.