Technical Data Sheet
| Document | RY-TDS-1108 |
|---|---|
| Revision | Rev. 1.1 |
| Issue date | October 2026 |
| Status | Issued |
Rayson SealForce · Waterproofing membranes
Rayson SealForce RW1 is a one-part latex waterproofing and bonding additive for cement-based work — mixed into renders, screeds, slurry coats, tile adhesives and grout to cut water penetration, strengthen the mortar and improve its bond and flexibility.
SealForce RW1 is a milky-white polymer latex that goes into a cement mix in place of some or all of the mixing water. As the cement sets, the latex fills the pores and binds the paste, so the render, screed, slurry or grout takes up less water, bonds harder to the surface behind it, bends further before it cracks and dusts less.
Additive.
Figure 1 — Typical system build-up (top to bottom). Layer thicknesses are system-dependent; confirm the specification for your project.
| Surface preparation | All surfaces must be sound, clean and free of movement, oil, grease, wax, curing compounds, release agents and loose material. New concrete must be at least 28 days old and render at least 7 days. Scabble painted surfaces to expose at least 80% of the original substrate, and clean old concrete and render thoroughly. Existing tiles must be sound and firmly bonded, then cleaned, degreased and abraded. |
|---|---|
| Mixing / dilution | One part. Stir before use, then mix it in at the stated ratio by volume; use fine sand under 0.5 mm for thin-set mortar and grout. Add no extra water beyond the stated dilution |
| Application method | Mixed into mortar, Brush (slurry coat), Roller (primer) |
| Coverage | Set by the mix rather than the area: in a slurry coat or thin-set tile mortar, 1 part RW1 to 1 part cement and 1 part sand by volume; in renders, screeds and grout, RW1 diluted 1:1 with water in place of the mixing water; as a primer or sealer, RW1 diluted with up to an equal volume of water. Rayson estimates the quantity for each job |
| Application conditions | Protect fresh work from rain, direct sun and drying wind. RW1 waterproofs the cement layer it is mixed into but does not bridge moving cracks; not for negative water pressure or permanent immersion. |
| Drying & curing | Lay render, screed or tiles onto a slurry coat while it is still wet, never over a dried slurry. Grout 24 hours after tiling; the tiled area can be used 24 hours after grouting. Protect fresh work from rain, direct sun and drying wind |
| Recoat interval | Lay render, screed or tiles onto a slurry coat while it is still wet. Grout 24 hours after tiling; the tiled area can be used 24 hours after grouting. |
| Film / thickness | Not a coating on its own: RW1 modifies the mortar it is mixed into. Mortar modified with RW1: compressive strength >50 N/mm², flexural strength >10 N/mm², bond strength >0.3 N/mm². |
| Pack sizes | 20 kg pail |
| Storage | Store in original, unopened, undamaged and sealed packaging in dry conditions, away from direct sunlight and frost. |
| Shelf life | 12 months from the date of production. |
Figure 2 — Application workflow. Each stage is a hold point: confirm the previous stage is complete and within specification before proceeding.
Water-resistant render or screed bonded to old concrete
Screed, tile bed and grout over SealForce WB20
Tiling over existing tiles
Water-based product. Cement mixes are alkaline: wear gloves and eye protection when mixing and applying, and avoid skin and eye contact. Clean tools with water while wet. Keep out of reach of children. Consult the Safety Data Sheet (in preparation) before use.