How to use SUMO S04 Tile & Stone Adhesive (wet areas, pools & heavy traffic)

In wet areas and pools, the waterproofing / tanking must be fully applied and cured before you tile — S04 bonds tiles, it does not waterproof. Check the membrane (e.g. SUMO SealCrete 2K Plus) is complete, cured and flood-tested, with fillets and reinforcement at the corners and penetrations.

The substrate must be sound, level, clean and free from curing compounds, grease and loose material. Confirm the falls run to the drain. Dampen highly absorbent surfaces and drain the excess.

Dry-lay, snap chalk lines and plan the layout to the drain falls. Plan movement joints — perimeter and intermediate — which are especially important in pools, over heated screeds and on large fields.

Pour two-thirds of the water in, add the powder slowly on low speed, add the remaining third, and mix to a smooth, lump-free, non-slump paste. Rest 2–3 minutes, then re-stir. Mix batches sized to the open time.

Key a firm skim onto the substrate with the flat trowel, then comb an even ribbed bed with the notched edge at ~45°, one direction. Comb only what you can tile before the ridges skin (S04 has extended open time, but wet-area heat can shorten it).

For wet areas, pools, large formats and heavy stone, back-butter the tile in addition to the combed bed. Full contact leaves no voids for water to pool behind the tile — critical underwater and in wet rooms.

Set each tile with a slide across the ridges, bed it with the mallet and beating block, and level with clips and a straightedge. Keep joints straight and consistent; check lippage.

Lift an early tile and confirm near-full coverage (≥90% for wet areas and exteriors) with solid corners. In a pool or wet room this is the difference between a lasting floor and one that lifts. Adjust and re-check.

Leave the planned movement joints clear of adhesive; clean adhesive off faces and out of joints before it sets. Wash tools immediately.

Let the adhesive cure (about 24 hours, longer in cool conditions) before grouting. For wet areas and pools, grout with SUMO Sumoxy epoxy grout (waterproof, stain-free, chemical-resistant), fill movement joints with a flexible sealant, and cure fully before filling a pool or using the wet area.