When a new roof is installed, the roofing contractor will usually fit a breathable membrane underneath the layer of tiles and over the joists, rafters and battens.
But why do they need to do this? A breathable membrane will give the roof a secondary method of protection against the worst the weather will throw at it. The primary protection is of course provided by the tiles on the surface of your roof, however if a tile is damage or slips the membrane will provide protection until the tile is repaired.
Breathable Membranes are really important as otherwise the roof will not be ventilated and may start to see problems caused by condensation, such as mould and mildew. Most breathable membranes are UV stable meaning they can be left exposed for some time before they are damaged by the sun. Most are also stable across a wide range of temperatures and are robust enough and tear also resistant so they can be handled and fixed to the roof battens easily.
When checking your roof it's always a good idea to look at the condition of the breathable membrane too, so if a tile fails the inside of your home will stay dry.
It might also be an opportunity to see whether you could upgrade the breathable membrane to one of the new hybrid insulated breathable membranes such as the Boost'R Hybrid Reflective membrane which will also improve the thermal performance of your roof along with maintaining the condensation levels.
If you are replacing or repairing a roof which has as loft conversion transforming it into living space, the additional parts of the Actis system, the H'Control Vapour control layer and the Hybris Insulation will further reduce heat loss in the room and in the house as a whole.
