Technical Reference

Treatment Procedures.

Step-by-step waterproofing, structural repair and rehabilitation methods, grouped by the chemistry they use, each mapped to the Armstrong products that carry it out. Select a treatment to view the full procedure and product recommendations.

Choose a treatment

Treatment · Polyurethane

Polyurethane Membrane

Premium high-elongation membrane, exposed or under tiles

Applications

Demanding terracesRoof gardens and party terracesBathrooms and sunken slabs (under tiles)Swimming poolsSTP and sewage structures

Procedure

Prepare the slab: clean, repair hollow patches and seal cracks with ROOFEXSEAL PU 212.
Exposed roofs: prime with RAINPROOF PU 400 diluted 2:1 with water.
Bed geo-fabric into the first full coat of RAINPROOF PU 400 on concrete, or fibre mesh on sheet roofs.
Apply the following coats of RAINPROOF PU 400 at right angles to the last.
Under tiles and in wet areas: apply ROOFCOAT PU 2K in two coats on a pre-wetted surface, crosswise, 3 to 4 hours apart, taken up the walls.
Air-cure ROOFCOAT PU 2K for 3 to 5 days, then flood-test before the screed and tiles go on.

Important Suggestions

RAINPROOF PU 400 is an exposed membrane and is not used under tiles. Under tiles use ROOFCOAT PU 2K. Take the membrane 2,000 mm up shower walls and at least 300 mm up other walls.

Why This Treatment?

Polyurethane is the premium choice: 700% elongation and adhesion above 2.0 N/mm² for the longest service on demanding roofs. ROOFCOAT PU 2K shows nil water penetration at 5 bar under tiles.

Recommended Products

RAINPROOF PU 400

Polyurethane waterproofing membrane for exposed roofs, 700% elongation.

ROOFCOAT PU 2K

Polyurethane-cement membrane for under-tile wet areas and STPs.

Dosage & Coverage

RAINPROOF PU 400 primerDiluted 2:1 with water

ROOFCOAT PU 2K6 to 8 sq.ft per kg in two coats

ROOFCOAT PU 2K cure3 to 5 days air cure before water