Keeping Your Flat Roof Cool

We’re in the midst of a heatwave here in the UK and homes are getting hotter. One drawback in the summer of a flat roof is its tendency to trap heat but there are plenty of ways to reduce heat absorption and keep your home cooler.

1. Consider Roof Coatings

Specialised roof coatings can help a flat roof reflect up to 90% of solar heat. Coatings come in a variety of materials such as elastomeric paint or large polyvinyl chloride (PVC) sheets with heat-sealed seams. Applying two coats of elastomeric paint in bright white will increase solar reflectivity by up to 75%. The polymer in the paint lets it expand and contract with the material on you roof.  This paint contains an elastomeric polymer that allows it to expand and contract along with the material on which it is applied.

Single-ply PVC membranes can be applied to structurally sound flat roofs. The best membranes can be expected to last around 40-50 years in varying weather conditions and can help keep your home cool in the summer especially if used in conjunction with rigid thermal insulation.

2. Install Insulation

It might sound counter-intuitive but a layer of rigid thermal insulation such as PIR (Polyisocyanurate) solid foam insulation will keep both heat and cold out of your home. It can be a big, and costly, job as you need to replace your ceilings to install the insulation directly under the roof.

3. Make a Slope

Create a low-sloped film shield over your flat roof. This can prevent the roof from absorbing light and heat by increasing solar reflectivity. But be careful to place it on a side away from prevailing winds – you don’t want to lose it!

4. Install a Green Roof

Green roofs are ideal for cooling houses and especially good for cooling in urban environments,  some reports say that a green roof can be up to 21 degrees cooler than a conventional roof.