Properly insulating your attic is one of the most important steps you can take to keep your home warm while dramatically driving down your utility bills. As is well known, heat rises, and up to 50% of of it can be lost through an inadequately insulated attic.
Insulating your attic using spray foam is a very simple process and can usually be completed in less than a day with a minimal amount of disturbance and mess. There are two types of foam insulation: Open cell and closed cell. Open cell is a breathable foam and is the one used in attic insulation and roof insulation. The open cell insulation allows moisture laden air within the attic to permeate through it where it will then pass into the outside environment through gaps and through roof tiles. This combats the buildup of "cold wet air" within the roof which would lead to mold growth and timber rot.
First, a breathable card membrane/ Vent card is installed between the rafters.
A a 50mm ventilation gap is left between the vent card and the roofing felt to prevent the buildup of moisture, allowing it to dissipate to the outside.
Next, the foam is simply sprayed onto the vent card to the desired thickness. It's as simple as that.
What is unique about spray foam insulation in comparison to traditional insulating materials, such as rock wool, fibre glass or cellulose, is that it expands into ever nook and gap of the roof space, providing an airtight seal which prevents the infiltration of damp cold air and more importantly wind.