Roof Slab with Polyurethane Foam, Tar and a Screed

1. The slab before

The roof was bare concrete with no protection from rain or sun.

2. Foam along the edges

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. goes along the edge, next to the wall. It fills the corners and joints, which are the weakest spots.

3. Tar

TarTarA black bitumen-based material spread hot or as a liquid emulsion. It seals the pores of concrete and keeps water out. is spread over the whole slab and seals the pores of the concrete.

4. The whole surface covered

The tar runs up to the low wallsParapetThe low wall around the edge of a flat roof or balcony. The joint between it and the floor is one of the most common places for leaks. and around the steel bars, so no spot is left bare under 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..

5. Laying the screed

The screed is spread over the tar and levelled with a vibrating screed board, which also compacts it.

6. A smooth surface

The screed covers the whole roof with no hollows, so rainwater can run off.

7. The result

The slab now has protection underneath and a solid, level surface on top.