Insulating A Roof Without Felt

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.

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. Add a preinstalled membrane to absorb and release the condensation as it forms with the natural weather cycle. If the roof is nailsick the slates should be removed with a proper slate ripper and checked for cracks and kept for reuse. Roofing felt may be necessary for use with your shingles to meet a class a fire rating when shingles are evaluated for their fire ratings it is done on a small test deck with the roofing felt underlayment in place without this underlayment the shingles alone may not meet the class a fire requirements.

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