Roof Insulated with Spray Polyurethane Foam and a New Screed

1. The bare slab

The roof was plain concrete with no insulationThermal insulationA layer of material that lets heat through only slowly, so a home keeps its warmth in winter and stays cool in summer. at all, so in summer the heat goes straight into the home below.

2. Spraying begins

Spray polyurethane foamSpray polyurethane foamA foam sprayed on as a liquid that expands on the spot and sets into one seamless layer. It insulates against heat and cold and closes cracks and joints. is sprayed straight onto the slab and bonds to the whole surface, even around the steel bars sticking up.

3. The whole roof insulated

The foam forms one continuous layer with no joints, so there are no gaps where heat can get in or out.

4. A coat of tar

A coat of tarTarA black bitumen-based material spread hot or as a liquid emulsion. It seals the pores of concrete and keeps water out. goes over the foam to protect it before the screedScreedA layer of sand-and-cement mix or lightweight concrete poured over the slab to create falls and a solid surface for the next material. is poured.

5. The concrete pump

The screed is pumped up to the roof, so it can be spread over the whole surface in one go.

6. The new screed

The screed covers and protects the insulation and gives a solid surface that can be walked on.

7. Levelling

The surface is levelled with a straightedge while it's still wet, so no hollows are left for water to pool in.