Insulating A Roof Without Felt

Traditionally we ve insulated the roof panel to try and keep the temperature on the panel from reaching the dew point.

Insulating a roof without felt.

The roof can usually be insulated under the rafters with sheet insulation and incorporate a vapour barrier. 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. If the roof is nailsick the slates should be removed with a proper slate ripper and checked for cracks and kept for reuse. 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.

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. He also found a water stain on the living room ceiling and recommended that the. When the home inspector checked the roof he found that the new shingles were installed without a layer of felt. Add a preinstalled membrane to absorb and release the condensation as it forms with the natural weather cycle.