Why is Spray Foam Insulation used
Spray Foam insulation is a liquid foam that is sprayed onto the underside of the roof pitches to provide an extra layer of insulation to the property.

Spray foam can be used in a number of insulation applications including: loft/roof, loft conversion, walls, floors, ceilings and to fill voids and gaps. It helps to reduce heat loss and draughts so reducing your energy bills and making your home feel more comfortable. Having Spray Foam in your home has its problems though.
Spray Foam Insulation and Dampness Problems
Should condensation be an issue, or dampness gets in, the result could damage roof trusses, battens, and purlins. All of which could start to rot. There have been reports of properties having very wet roof timbers due to spray foam insulation having been installed. The result is a degradation in your roof’s condition.
Polyurethane, the most common type of spray foam insulation, was developed in the 1940s and used primarily on airplanes. It wasn’t until the 1970s that it started to be used as foam insulation.