Why shall I use it

You must guard against the damaging affects of condensation in a roof space because modern homes have eliminated drafts; hence there is less dispersion of the vapour (steam, air bourn moisture) that every home is generating in greater quantities. The roof space has become a buffer between the warm home and the cold outside and the vapour will travel through many materials (but most commonly the loft hatch) and will form condensation as it cools on the coldest areas (usually the under felt). This condensation can also contain bacteria and, if left unchecked will instigate mould growth that can manifest in many ways and could seriously damage your home.

Second generation breather will meet all your requirements

Part 'E' of the approved documents (conservation of fuel and power) is fast becoming the Government's political tool and pressure to save energy is becoming the main issue in modern building design.

The energy efficient cold non-vented and warm roof style can only be undertaken using breather membrane technology. By eliminating the drafts which are part of a traditional roof space, the heat loss can be reduced by up to 25%.

Recent conceptual modals and test rigs have shown that a vapour resistance of 0.16MNsg^-1 [ Permavent 0.15MNsg^-1, Permavent-MAX-0.15MNsg^-1, Permavent-ECO-0.11MNsg^-1] is equivalent to 10mm continuous ventilation on small roofs and is the best performance level of breather membranes. Permavent is being proven as the right choice of roofing membrane.

Why Permavent?

For non-vented roofs a good quality three-layered polypropylene (or polyethylene) permeable membrane with a vapour resistance of not less than O.25MNsg^-1 such as Permavent (0.15MNsg^-1) is a requirement of the building regulations. For vented roofs, bitumous roofing felts are heavy, bulky, easily damaged during installation and become brittle through time as well as creating the 'plastic bag’ effect with vapour problems.

Permavent is a very well suited product to the new build and refurbishment market. It is light and easy to use with a typical usage ratio of one roll of Permavent to five rolls of bitumous felt, it is surprisingly cost effective as a percentage of the new roof. Its tough design will virtually eliminate installation damage. It is UV stable for three months that enables a delayed covering of the roof tiles and will stay watertight and perform well for many years. Although roofs that require active ventilation work well, they must maintain this, and non-permeable membranes do not lend themselves to future changes to the home. Permavent is a highly adaptable modern system product that will help to create a healthy home whilst being cost effective.

Permavent is versatile to use on each of the four main roof constructions . It offers good watertight properties, excellent vapour permeability, durability and strength.