Spray Polyurethane Foam on a Corrugated Roof and a Flat Roof
On the same building, the pitched corrugated roof and the flat roof were both sprayed with polyurethane foam. On the flat roof the foam was finished with a white coat that shields it from the sun.
Step by step
1. The roof before
The roof was made of corrugated sheets, with joints and screws all along it. That is where water gets in, and the sheets get very hot in the sun.
2. Spraying the pitched roof
The polyurethane foam is sprayed strip by strip. You can see the difference between the bare sheets and the part already insulated.
3. The ridge
The ridge, where the two slopes meet, is covered with extra care, because it is the most exposed spot.
4. Over the joints
The foam follows the waves of the sheets and covers the joints and screws in one continuous layer that also keeps the heat out.
5. The flat roof
The flat roof of the same building already has a black primer. The foam is sprayed on top and covers it section by section, even around the steel bars sticking out of the slab.
6. The chimney
The whole flat roof is covered in one continuous layer of foam that insulates and waterproofs at the same time. The chimney is sprayed at its base so it joins the rest of the surface watertight.
7. White coat
Foam cannot stand up to the sun on its own. A white protective coat covers it and reflects the heat.
8. The result
The coat reaches right to the foot of the solar heater and around its pipes. Both the pitched roof and the flat roof are now insulated, with no open joints.