Tile Adhesive and Epoxy Grout: The Right TILEX for Tile Fixing and Grouting

Tile fixing: check the surface, the tile and the location first

Tiles that sound hollow, tiles coming loose from the floor, wall tiles falling, and tile joints turning black or cracking are the complaints behind most searches for a tile adhesive or an epoxy grout. Nearly all of them trace back to a choice made before the first tile was laid: an adhesive that did not suit the surface or the tile, or a grout that did not suit the room. Tile fixing and grouting done right starts with four checks.

Find the right tile adhesive and grout for your job

Match your job to one route. Each takes you to the section that covers it.

A tile is only as good as the bed under it. Full contact, the right adhesive, movement joints and a grout made for the room: those four decide how long the floor lasts.

Tile adhesive and grout finder

Armstrong makes TILEX adhesives and grouts for different surfaces, tiles and joints. Each is made for a job, and none is a lesser choice. Answer three questions for a starting recommendation, then confirm it with an Armstrong expert.

Best tile adhesive for floor and wall tiles: choose TILEX by job

The table lists every TILEX adhesive that suits each job. Where more than one fits, pick the one that suits the site, and ask an Armstrong expert if unsure.

TILEX 521 and TILEX 512 are both two-component D2TES2 adhesives, and both fit large-format tiles, stone, boards and tile on tile. Use whichever your distributor stocks, or ask an Armstrong expert.

Tile adhesive or cement mortar: why the bed matters

Waterproofing comes before tiling in every wet area. The bathroom waterproofing and balcony and podium waterproofing pages cover the coating that goes under the tile bed.

How to fix tiles with tile adhesive, step by step

The method is the same for floors and walls. What changes is the adhesive, the trowel and how much care the surface needs.

1. 1
   Prepare the surface

   It must be structurally sound, clean and free of dirt, oil, grease, laitance, sealers and curing compounds. Remove all loose, hollow and flaking plaster or old adhesive. Check it is true to level and plumb, and level rough surfaces first.Why: Adhesive bonds to sound, clean surfaces. Dirt, oil, sealers and curing compound stop the bond.
2. 2
   Check the age of the concrete

   A slab should be cured and 28 days old before tiling with a water-mixed adhesive. Where TILEX URP ADMIX 73 replaces the water in TILEX 351 PLUS, that wait is not needed.Why: A slab still shrinking and drying pulls tiles off. Waiting for it to cure avoids hollow, cracking tiles.
3. 3
   Dampen, do not soak

   Dampen concrete or masonry and sweep off any standing water.Why: Dry concrete pulls water out of the adhesive and weakens the bond, while standing water weakens it too.
4. 4
   Mix the adhesive

   Put the water in the bucket first and add the powder to it. TILEX 351 PLUS takes 5.5 to 6 litres per 20 kg bag. TILEX 353 takes 5 litres per 20 kg bag for grey and 6 litres for white. Mix to a smooth paste, let it stand for 5 minutes and mix again. For TILEX 512, mix Part A liquid and Part B powder at 1 to 3 by weight, and use it within its 30 minute pot life. TILEX EPOXY ES 301 is mixed 1 to 1.Why: Water first and powder after gives a lump-free mix, and the stated water gives the stated strength.
5. 5
   Comb the bed with a notched trowel

   Spread the adhesive and comb it in one direction. A 6 mm by 6 mm square notched trowel gives an average bed of 3 mm. Spread only as much as you can tile within the 30 minute open time.Why: Combing leaves ridges that collapse into a full bed when the tile is pressed in, with no voids under the tile.
6. 6
   Set the tiles

   Press each tile into the wet adhesive with a slight twist and bed it with a rubber mallet. Back-butter tiles larger than 12 inches by 12 inches so the whole back is in contact. Lift a tile now and then to check the coverage.Why: Pressing with a twist and bedding with a mallet pushes out air. Back-buttering large tiles fills the voids a comb leaves.
7. 7
   Keep the joints even

   Use spacers. Do not butt tiles tight together. Epoxy-grouted joints are specified at 3 to 5 mm with nylon spacers.Why: Spacers keep joint width equal, which keeps the grout sound, and tight tiles crack under movement.
8. 8
   Provide movement joints

   Carry every expansion and construction joint in the structure up through the tile work. Leave a joint at the perimeter, at changes of plane and at corners. Fill these with ROOFEXSEAL PU 212, a flexible polyurethane sealant, and never with grout.Why: Slabs move. A tile bed without movement joints cracks along the same line.
9. 9
   Wait, then grout

   Allow a minimum of 24 hours before grouting. Floors fixed with TILEX 351 PLUS take heavy traffic after 16 to 24 hours. Floors fixed with TILEX 512 take foot traffic after 24 hours.Why: The adhesive must set before grouting, or the tiles shift and the joints crack.

Tile on tile adhesive: fixing new tiles over old tiles

New tiles can be laid over old ones when the old tiles are firmly bonded, level and clean. It saves breaking out the floor, and it raises the floor level by the thickness of the new tile and bed, so check door clearances and thresholds first.

1. 1
   Tap every old tile

   Remove any tile that sounds hollow or is loose, and fill the patch level with adhesive or repair mortar.Why: A hollow tile is already coming off. Fixing new tiles over it fails with it.
2. 2
   Clean and key the surface

   Remove grease, soap film and polish. TILEXKLEEN AC / DA / LC DA is the de-greasing agent. With TILEX 350, scrape the old tile surface to give a mechanical key.Why: Soap, grease and polish stop adhesive bonding to the old tile, so the glaze is cleaned and keyed.
3. 3
   Fix with a tile on tile adhesive

   TILEX 521 is trowelled straight onto the existing tile surface, and the new tiles are installed within its 30 minute open time. TILEX 512 and TILEX 351 PLUS are also listed for tile on tile.Why: The special adhesive bonds to the existing glaze, so there is no need to strip the old tiles.
4. 4
   Offset the joints and grout after 24 hours

   Do not line up new joints over old ones. Keep the existing movement joints.Why: Joints over joints let any movement in the old floor crack the new one.

In a bathroom, tile on tile does not repair a leak. If the old floor leaks, follow the bathroom waterproofing page first.

Fixing tiles on gypsum board, plywood, cement board and MIVAN walls

• Check with the board manufacturer that the board can carry the weight of the tile or stone, and follow their fixing method so the board cannot move, warp or bend.
• Use TILEX 512, mixed 1 to 3 by weight, or TILEX 521, at a 3 mm bed with a 6 mm by 6 mm notched trowel.
• Carry the joints between adjacent boards up to the tile surface. Do not let adhesive enter the gaps between boards.
• Fill the joints over board joints, changes of plane and corners with ROOFEXSEAL PU 212, not with rigid grout.

Epoxy grout or cement grout: choosing the tile joint filler

The grout is chosen by two things: the width of the joint and what the joint will be exposed to. Tile joints turning black, grout cracking outdoors and grout washing out of a pool are all cases of the wrong grout for the exposure.

How to fill tile gaps with cement grout

1. 1
   Let the adhesive cure

   Wait a minimum of 24 hours after fixing. Rake out any adhesive that has squeezed into the joints and clean them.Why: Grouting too soon moves the tiles and weakens the joints.
2. 2
   Mix to a smooth paste

   Add the grout to clean water, or to TILEX URP ADMIX 73 for wet areas. Keep sanded grout stiff enough to hold its shape.Why: A smooth paste fills joints fully. A thin paste shrinks and cracks, and a latex admix makes wet-area grout dense.
3. 3
   Force it into the joints

   Work the grout in with a rubber float held at 45 degrees, filling every joint to full depth.Why: Holding the float at 45 degrees packs grout to full depth, with no voids for water.
4. 4
   Clean before it hardens

   Remove the excess and polish the tiles with a damp sponge.Why: Grout dried on the tile face is very hard to remove.
5. 5
   Cure

   TILEX TG U 1600 cures in 24 hours. TILEX TG S 1500 needs 24 to 48 hours before it sees water.Why: Grout kept from water during cure reaches its full strength and density.

Epoxy putty for tile joints on a sump or leaking floor

Tile joints in a sump, a wet floor or a pool-side area are the first place water gets in. Replacing the old filler with epoxy putty makes the joint dense, water-tight and chemical-resistant. Doses, thicknesses and coats are the standard figures; the site and the exposure decide where they move.

1. 1
   Open the joints

   Open the tile joints to a U-groove with a groove-cutting machine, to at least 12 mm depth, and clean them.Why: Epoxy needs depth to hold. A shallow joint just pops out.
2. 2
   Fill with epoxy putty

   Remove the old joint filler, then fill the joints with TILEX EPOXY SP 100, the epoxy joint putty, at a joint width of 3 to 5 mm held with nylon spacers on new work.Why: The epoxy fills the joint solid and does not absorb water the way cement grout does.
3. 3
   Set expectations

   Filling the tile joints alone does not guarantee that a sump or tank will stop leaking, because the water can pass under the tiles. If it keeps leaking, the tiles and bed have to be treated.Why: This is an honest limit of the method. The joint is only the visible part of the leak path.

How to apply epoxy grout

1. 1
   Clean the joints, with no acid

   Remove debris and sponge off dust. Do not clean the tiles with acid cleaners before or after epoxy grouting.Why: Acid damages epoxy grout and the finish, and debris stops it filling to depth.
2. 2
   Check the temperature

   The surface must be between 16°C and 32°C.Why: Epoxy cures outside its temperature band slowly, or too fast to work with.
3. 3
   Mix all three parts

   Empty Part A and Part B into a clean pail and blend fully. Add Part C filler and mix to a uniform, stiff consistency. Add nothing else.Why: All three parts mixed fully cure fully. Unmixed streaks stay soft and stain.
4. 4
   Pack the joints

   Work the grout in by float or caulking gun until every joint is full, and remove the excess with a grout float. Leave no grout on the tile face.Why: Epoxy has no second chance once it cures, so every joint is filled full and excess is removed at once.
5. 5
   Clean on time

   After 30 to 40 minutes, scrub the tiles and joints with clean water and a scrubber. Drag a clean thick towel across to lift the residue. Within 24 hours, wash with ordinary soap to remove any haze.Why: Epoxy residue sets hard on the tile face, so cleaning has to be done in the stated window.
6. 6
   Protect outdoor work

   In open areas, cover the work from direct sunlight for 7 days.Why: Direct sun on fresh epoxy makes it cure unevenly and discolour.

Cleaning cement haze, grease and stains from tiles

TILEXKLEEN AC / DA / LC is a range of three cleaners. AC is an acid cleaner for cement haze, grout residue and rust on newly laid tiles. DA is a de-greasing agent for oil and grease. LC is a light cleaner for general cleaning. Dilute each as its label says, let it dwell, scrub and rinse well. Test on a hidden patch first on marble and granite, and keep the acid cleaner away from epoxy grout work.

Tiles sounding hollow, coming loose or cracking: what to do

Start with the smallest repair that reaches the cause. Relaying the whole floor is the last resort, for the case where the bed has failed across the room.

Refixing loose tiles without relaying the floor

1. 1
   Map the hollow area

   Tap every tile and mark the ones that sound hollow. If only a small part of the floor is marked, a local repair is right.Why: Tapping shows exactly which tiles are hollow, so only those are lifted and the repair stays small.
2. 2
   Lift the marked tiles

   Cut out the grout around them first so the neighbours are not chipped.Why: Cutting the grout first protects the neighbouring tiles from chipping.
3. 3
   Remove everything loose

   Chip off the old bed and all loose, hollow or dusty material down to a sound surface. Clean the backs of tiles that will be reused.Why: A new bed bonds only to a sound surface, and only to clean tile backs.
4. 4
   Refix in a full bed

   Comb the adhesive, back-butter the tile and press it in level with its neighbours.Why: A full bed with no voids under the tile stops it going hollow again.
5. 5
   Grout after 24 hours

   Match the existing joint, or regrout the room for an even colour.Why: The adhesive must set before grouting, and matching the joint hides the repair.

When the floor has to be relaid

Where the bed has failed across the room, the tiles and bed are removed, the surface is made sound and level, any wet area is waterproofed and tested, and the tiles are laid again with the adhesive that suits the surface. Where the old tiles are firm but dated or stained, tile on tile is the less drastic option.

A damp patch under the tiles or on the ceiling below is a waterproofing problem, not a tiling problem. See bathroom waterproofing or terrace waterproofing.

Tile adhesive types and classes: C2TE, S1, S2 and IS 15477 explained

Tile adhesives are classified by the same codes on every bag. Knowing what the letters mean makes it easy to read a specification and to compare the TILEX adhesives.

What the letters on a tile adhesive bag mean

The code meanings above summarise the published EN 12004 and IS 15477:2019 standards.

This page covers choosing and using the products. The longer guide on how to choose tile adhesive and grout explains the reasoning behind each choice.

Tile fixing and grouting products by stage of work

How much tile adhesive and grout for a 10 ft by 12 ft room

Approximate quantities for a floor of 120 sq.ft, worked out from each product's stated coverage at a 3 mm bed on a level surface. Uneven floors, deeper beds and back-buttering use more. An Armstrong expert confirms the final quantity after seeing the site.

Standards and tests for tile adhesives and grouts

• IS 15477:2019 is the Indian standard for adhesives used with ceramic, mosaic and stone tiles.
• EN 12004 and ISO 13007 classify tile adhesives by type, adhesion, slip, open time and deformability.
• ANSI A118.4 sets shear bond strength requirements for modified cement adhesives. TILEX 351 PLUS exceeds them on glazed wall tile, porcelain mosaic and quarry tile, including after water immersion and freeze-thaw cycling.
• TILEX 512: tensile adhesion above 1.5 N/mm² and shear adhesion of 5.0 N/mm² or more after water immersion and thermal shock.
• Performance figures are from Armstrong laboratory testing under controlled conditions. Site results vary with the surface, the weather and workmanship.

Tile adhesive and grout quantity calculator

Enter the area to be tiled to see the adhesive and grout needed at a 3 mm bed. Quantities only.

Eight mistakes that make tiles come loose or joints fail

1. Using one adhesive for every job. A standard adhesive on a board, an old tile or a large slab is the commonest cause of debonding.
2. Laying tiles on dabs. Voids under the tile crack under load and fill with water.
3. Tiling on young concrete. A slab that is still shrinking pulls the bed off. Wait 28 days, or gauge TILEX 351 PLUS with TILEX URP ADMIX 73 in place of water.
4. Tiling over loose or dusty surfaces. The adhesive bonds to whatever is under it. Remove everything loose first.
5. Leaving out movement joints. Tiles butted tight with no joints lift and tent when the floor heats up.
6. Spreading too far ahead. Adhesive that has skinned over past its open time does not bond.
7. Grouting too early. Grouting before 24 hours disturbs tiles that have not yet set.
8. Using plain cement grout in wet or stained areas. It is porous. Use latex-modified or epoxy grout there.

Tile fixing and grouting questions and answers