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.

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Treatment · Joint, crack & leak sealing

Terrace & Concrete Crack Sealing

Polyurethane sealant for moving cracks

Applications

Terrace cracksConcrete floor cracksWater-retaining structuresFaçade and cladding jointsDoor and window perimeters

Procedure

Prepare the surface thoroughly.
Open each crack to a U or V groove at least 6 mm wide and 6 mm deep with a sharp chisel or concrete cutter.
Clean the groove with wire brushing and an air blower.
Mask both edges with tape.
Fill with ROOFEXSEAL PU 212 in one continuous run, at least 6 mm wide and 6 mm deep. Roof cracks take PU 212; expansion joints take ROOFEX-SEAL PS.
Remove the tape and apply two coats of ROOFCOAT FLEXI 100 over the groove, or carry on with the roof coating.

Important Suggestions

Open cracks to 6 to 10 mm width and depth before sealing; a sealant laid over an unopened crack has nothing to grip.

Why This Treatment?

Concrete moves with heat. Cement and bitumen fillers crack again, while a polyurethane sealant stays flexible (±25% movement, elongation above 600%) and keeps water out of the crack.