What you’ll need
Step by step
Wait for the adhesive to cure first
Only grout once the tile adhesive has fully cured (see its datasheet). Grouting over a soft bed shifts tiles and traps moisture under them.
Clean and prepare the joints
Rake out any adhesive that has squeezed up into the joints and vacuum the dust. Joints must be a consistent depth and clean and dry, so remove spacers and wipe faces down.
Mix the two parts thoroughly
Combine the resin and hardener of Sumoxy 2K in the correct ratio and mix to a completely uniform colour — streaks mean unmixed hardener and soft spots later. Only mix what you can use within the working time.
Pack the grout diagonally
Spread firmly across the tiles at 45° to the joints with the epoxy float, packing each joint full with no voids. Working diagonally stops the float digging the grout back out of the joint.
First clean while it is still workable
Before the grout skins, wipe diagonally with a damp (not wet) scotch pad and sponge to emulsify and remove the bulk of the residue. Change the water often — dirty water just spreads haze.
Second clean to remove haze
Follow with a clean damp sponge pass to lift the fine epoxy film. For any stubborn haze that remains, use SUMO Sparkle epoxy haze remover per its instructions.
Let it cure before use
Keep the area dry and unused while the grout cures fully. Only then does it reach its stain- and water-resistant best.
What to avoid
Epoxy has a short pot life. A large batch goes off in the bucket before you have used it. Mix little and often.
Cured epoxy film is very hard to remove. Do the first clean while the grout is still workable.
Streaky, unmixed grout has soft, tacky patches. Mix to a uniform colour.
It shifts tiles and traps water. Wait the full adhesive cure time.