Sound, clean, and reasonably flat
Those three words cover nearly all of it. Maira Tile Bond 3100 fixes over concrete, cement screeds and cement mortars or render — but every one of those has to be sound, clean, and free of dust, grease and loose material before you start.
Dust is a release layer
This is the one that gets underestimated. A fine layer of dust on a screed means the adhesive bonds beautifully — to the dust. And the dust is attached to nothing.
Sweep, then vacuum if you can. On a dusty slab, wipe down with clean water and let it come back to damp rather than wet. Do not tile over a floor you have just been cutting tiles on.
What to remove first
- Grease and oil — degrease it; adhesive will not bond through it.
- Curing compound and laitance — the weak, powdery skin on a new slab has to come off mechanically.
- Old paint or flaky render — if it lifts with a scraper, it will lift with your tiles on it.
- Old adhesive ridges — knock them back flat rather than tiling over them.
The blunt test: if a layer will not survive being scraped hard, it is not a substrate.
Flatness saves money
Adhesive is not a levelling compound. Filling a wavy floor with it costs far more than levelling the floor properly, and it leaves thick patches that shrink and cure differently from the thin ones around them.
Check across the floor with a long straightedge. Where the gaps are real, level the substrate first — it will be cheaper than the extra bags, and much cheaper than lifting tiles later.
Dampen very dry substrates
A parched screed in summer behaves like a sponge. It pulls the mixing water out of the mortar before the cement can hydrate, and you get a weak, dusty bond and a very short working time.
Dampen it before you start — damp, not wet, with no standing water or puddles. Excess water on the surface causes the opposite problem.
Let new work cure
New concrete and screeds carry a lot of moisture and shrink as they dry. Tiling too early means tiling onto something still moving. Give new substrates the drying time your specification calls for; if you are unsure on a specific slab, ask before you tile rather than after.
Heated screeds and exteriors
Heated floors need commissioning before tiling, and the heating off while you work. Exterior substrates need falls so water runs off rather than ponding. Both are covered in tiling outdoors and over heated floors.
The five minutes that pay for themselves
Before the first bucket goes in: sweep it, run a straightedge over it, check nothing is loose, and damp it if it is bone dry. That is the whole routine, and it prevents more callbacks than anything else on site.
Note: the figures here are typical values for Maira Tile Bond 3100 and are given as guidance. Real results vary with substrate, tile format, trowel size, temperature and site conditions. Confirm quantities and working times with Ali Traders before you order or start work.