underlayment

Our problem area is roofs with the older black sarking felt as they don''t breathe.

We ventilate roof spaces by a variety of ways, such as airbricks in end walls or a sarking felt under slates that "breathes" and lets moisture out.

If you have an old slate or tile finished roof then it's probable that there is no sarking felt beneath the slates, so it will breathe happily.

Slate or tile roofs installed before the Second World War rarely had any sarking felt beneath the slates or tiles.

The slow seeping leak was being caught by the underlining of sarking felt, until last Friday when a full day of rain burst its way through and on to the bathroom ceiling.

The water was leaking out of the sarking felt below the roof tiles.

Cavity walls, damp proof courses and sarking felt under the roof tiles, all contribute to the resistance to damp and the weather.

This sarking felt catches any water that leaks between the tiles or slates, draining down into the eaves and then into the gutter.