No Roof Felt

Slate roof with no roofing felt

Slate Roof No Felt


The majority of properties over 50 years old will not have a felt or membrane of any kind underneath the roof tiles, provided that the property has not been re-roofed more recently of course. A lot of older properties also have a mortar pointing of kinds on the inside of the roof, usually ending up on the floor of the loft after a while. Having no roof membrane, or having underpointing, on the roof does not in itself present a problem with the roof. Some roofing or building companies, and sometimes building surveyors, will tell you that a property must have a membrane and therefore any without need re-roofing. This is not the case in the vast majority of properties, as they have had no membrane since they were built.

On modern roofs, which are fitted with breathable membranes, if a problem occurs with the roof leading to water coming through, the membrane acts as another line of defence and will re-direct the leak down to the gutter. Older properties with no membrane do not have this defence and therefore the leak comes straight through to the inside, can get messy but at least you know there is a problem. When a membrane is constantly re-directing leaking water, the lifespan of the membrane will be greatly reduced and will eventually perish.

Tiled roof with no roofing felt or membrane

Tiled Roof No Felt


If you have an older property which has no felt under the roof, or your felt has perished or begun to, our spray foam insulation system can help. Provided that your roof is repaired by us prior to installation, spray foam will replace the need for a membrane and will also guarantee your roof, something which a membrane cannot. Foam insulation can also be used over old mortar underpointing, this will seal and guarantee the roof as well as stopping the old mortar falling into your loft.

Spray foam insulation applied directly to the inside of your roof, to the relevant depth, will prevent any future leaks through the treated areas, it will also prevent condensation forming on the roof interior. Sprayed foam roof insulation will effectively seal your loft area creating a warm-roof when installed to the relevant depth, this prevents the build up of condensation even in the most severe winter weather and will protect timbers from moisture damage.

Roofing membrane replaced by spray foam insulation

Felt Replaced with Foam Insulation