Cuts water penetration through cement renders, screeds, slurry coats and grout
Waterproofing additive for cement renders, plaster and screeds
Rayson SealForce RW1
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.
Best for
Best for the cement layers of wet areas and renovations — water-resistant render, screed and slurry coats, tile bedding and grout, tiling over existing tiles and bonding new work to old concrete — alongside a SealForce membrane wherever the waterproofing has to bridge cracks.
Real product · Interactive depth view Rayson SealForce
Product system Rayson SealForce RW1
20 kg pail RY-TDS-1108
Rayson SealForce RW1 has one clearly defined, verifiable job in the coating system.
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. Best for the cement layers of wet areas and renovations — water-resistant render, screed and slurry coats, tile bedding and grout, tiling over existing tiles and bonding new work to old concrete — alongside a SealForce membrane wherever the waterproofing has to bridge cracks.
Mortar modified with RW1: compressive strength ≥40 N/mm² and flexural strength ≥8 N/mm²
Slurry coat that seals concrete and masonry, and bonds new render, screed or tiles to old concrete
Bond strength ≥0.25 N/mm² — for marble, granite and homogeneous tiles
Additive for cement-sand mortars and tile adhesives: ceramic and homogeneous tiles, marble, granite and natural stone
Mix it in. Keep the water out.
A one-part latex additive that waterproofs and strengthens renders, screeds, slurry coats, tile beds and grout, and bonds new cement work to old.
A controlled route to applying Rayson SealForce RW1.
This sequence supports early planning. It does not replace the current Technical Data Sheet, approved method statement or project-specific technical review.
- 01
Inspect and prepare the substrate
Concrete at least 28 days old, and render at least 7 days old
- 02
Prepare the material as specified
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
- 03
Apply with the correct tools
Recommended methods: Mixed into mortar, Brush (slurry coat), Roller (primer). Confirm coat count and thickness for the project.
- 04
Protect through the required cure
Lay render, screed or tiles onto a slurry coat while it is still wet, never over a dried slurry. Grout no sooner than 24 hours after tiling, and keep traffic off for at least 48 hours after grouting. Protect fresh work from rain, direct sun and drying wind
Coating system cutaway
Every layer has a job—from prepared substrate to service surface.
This diagram explains a typical system position, not a fixed specification. Primer, body coat, finish, thickness and detailing must be confirmed for the project.
Position in the system Additive
Rayson SealForce RW1 serves as the additive. Confirm the complete build-up against the substrate, exposure and project requirements.
Related system products
Review primers, body layers, finishes or specialist components connected to this product.
- Rayson SealForce RW1Additive · Latex
- Approved primer / baseIncluded when required by the system design
- Correctly prepared substrateConcrete at least 28 days old, and render at least 7 days old
Four project facts for faster system screening.
These current product figures support early selection. Confirm the final build-up, quantity and application conditions against the Technical Data Sheet and site conditions.
- Coverage
- Coverage
- Mixing & working time
- Mixing
- Drying & curing
- Curing
- Pack configuration
- Pack
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
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
Lay render, screed or tiles onto a slurry coat while it is still wet, never over a dried slurry. Grout no sooner than 24 hours after tiling, and keep traffic off for at least 48 hours after grouting. Protect fresh work from rain, direct sun and drying wind
20 kg pail
Confirm the substrate and real service environment before specifying.
Choose it when
- Waterproofing additive for cement renders, plaster and screeds
- Slurry coat that seals concrete and masonry, and bonds new render, screed or tiles to old concrete
- Additive for cement-sand mortars and tile adhesives: ceramic and homogeneous tiles, marble, granite and natural stone
- Tiling over existing tiles
- Tile grout additive for a stronger bond and better water resistance
- Injection into hollow plaster and screed to restore the bond
Relevant applications
Choose something else when
- Waterproofs the cement layer it is mixed into but does not bridge cracks that move: toilets, bathrooms and balconies under tiles take SealForce WB20 as the membrane
- Not for basements against groundwater, water-retaining structures or permanent immersion
- Sound substrates only: new concrete at least 28 days old, render at least 7 days; remove paint and coatings mechanically first
- Apply between +10 °C and +35 °C; protect fresh work from rain, direct sun and drying wind
- Keep to the stated dilution: extra water weakens the mortar
- Over existing tiles, clean, degrease and abrade the glaze, and trial the bond first
- The only waterproofing under tiles in a toilet, bathroom or balcony — use SealForce WB20
- Planters, decks and other surfaces that move or crack — use SealForce RC30
- Basements against groundwater, water-retaining structures and permanent immersion
- High-strength repairs on vertical, overhead or mat-damp concrete — use PatchBond TX80
Other Rayson products to evaluate
These links continue the comparison; they are not automatic substitutes. Confirm the substrate, exposure and complete build-up before selection.
For the waterproofing membrane beneath the tiles of a toilet, bathroom or balcony Rayson SealForce WB20 Evaluate ↗ For a planter, deck or other surface that moves or cracks Rayson SealForce RC30 Evaluate ↗ For a high-strength epoxy repair on vertical, overhead or mat-damp concrete Rayson PatchBond TX80 Evaluate ↗
Substrate requirements+
- Concrete at least 28 days old, and render at least 7 days old
- Blockwork and rendered brickwork
- Existing tiles that are sound and firmly bonded, then cleaned, degreased and abraded
- Old concrete and render cleaned thoroughly, with paint and coatings removed mechanically to the sound substrate
- All surfaces sound and free of oil, grease, wax, curing compounds, release agents and loose material
Technical documents and project support
Ready to specify Rayson SealForce RW1? Give Rayson the site conditions.
Send the area, substrate condition, expected traffic or exposure, required finish and programme. The technical team can help review the system build-up and estimated quantity.
What to know before specifying Rayson SealForce RW1.
What is SealForce RW1 used for?
It is mixed into cement-based work to make it more water-resistant, stronger and better bonded: renders, plaster and screeds; slurry coats that seal a surface and bond new work to old; tile adhesives and thin-set mortar, including tiles over existing tiles; tile grout; and patching and re-pointing. Diluted, it is also a primer and sealer for absorbent cement surfaces, and an injection that re-bonds hollow plaster and screed.
Is RW1 a waterproofing product?
Yes, for cement work: mixed into a render, screed, slurry coat, tile bed or grout, it cuts water penetration and makes the layer denser and stronger. What it cannot do is bridge a crack that moves, so where the waterproofing has to survive movement — a toilet, bathroom or balcony under tiles, a flat roof or a planter — the membrane is SealForce WB20, AC10 or RC30, and RW1 waterproofs and strengthens the cement layers around it.
How do I mix it?
By volume. Slurry coat or thin-set tile mortar: 1 part RW1, 1 part cement and 1 part sand, with fine sand under 0.5 mm for thin-set work. Renders, screeds and grout: RW1 diluted 1:1 with water, used in place of the mixing water. Primer or sealer: RW1 diluted with up to an equal volume of water and rolled onto a clean surface. Add no extra water.
Can I tile over existing tiles with it?
Yes, if the old tiles are sound and firmly bonded: replace any hollow ones, clean, degrease and abrade the glaze, brush on an RW1 slurry coat and bed the new tiles while it is still wet. Trial the bond on very smooth or polished tiles first. Overlaying is also how a new HDB flat is re-tiled in its first three years, when hacking the bathroom tiles is not allowed.
How long before grouting and use?
Grout no sooner than 24 hours after tiling, and keep traffic off for at least 48 hours after grouting. Lay render, screed or tiles onto a slurry coat while it is still wet, never over a dried slurry.
Can it bond new concrete or render to old concrete?
Yes. Clean and roughen the old surface, remove paint and contaminants, brush on a slurry coat of 1 part RW1, 1 part cement and 1 part sand, and place the new render, screed or concrete while the slurry is still wet.
SealForce RW1 or PatchBond TX80 for a repair?
RW1 strengthens cement-based patching, render and re-pointing — the economical repair for floors, walls and plaster. PatchBond TX80 is a two-component epoxy repair compound for higher-strength, non-sag repairs on vertical, overhead or mat-damp concrete.
Is SealForce RW1 available to order now?
SealForce RW1 is part of Rayson's upcoming waterproofing release. Send the project details and your required date, and Rayson will confirm supply timing, quantities and, where you need one, an applicator in the Rayson network before you commit.
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