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.
Polysulphide Sealant for Expansion Joints
Joint sealing for thermal movement
Applications
Procedure
- Clean out the joint: rake out old sealant, mortar, bitumen and debris to the sealant depth, leaving sound filler board in place below. Faces must be sound, clean and dry.
- Rebuild chipped edges with ROOFCRETE AR 576 or a 1:4 polymer cement mortar with ROOFBOND SBR 401, forming a groove about 25 mm wide and 25 mm deep.
- Insert a backer rod or polyethylene foam to set the depth: width to depth 2:1 for butt joints, 1:1 for floor joints.
- Mask both edges with tape.
- Brush ROOFEXSEAL PRIMER PS / NPS on both faces: PS on porous faces, NPS on glass, steel or glazed tile.
- Mix ROOFEX-SEAL PS fully and fill from the bottom up in one continuous run: gun grade for vertical and overhead joints, pour grade for horizontal joints.
- Tool the surface slightly concave and remove the tape. Protect while it cures for 7 days at 20°C. On terraces, take the roof coating up to the joint edges but not across the sealant, so the joint stays free to move.
Important Suggestions
Any covering on the original joint must be broken out to expose it. Use ROOFBOND EP as the bonding agent on heavy structures. Joints of 6 to 25 mm are filled in one application; wider joints up to 50 mm in more than one.
Why This Treatment?
Expansion joints open and close with temperature. Cement and bitumen cannot take this and fail. Polysulphide sealant stays rubbery and accommodates the joint's cyclic movement, keeping water out.
Recommended Products
Dosage & Coverage
Related Solution Guides
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