Floor construction
Timber and mineral floors behave differently. The build-up must suit the actual substrate rather than follow one standard recipe.
Preparation before tiling
Floor Preparation Cost Before Tiling (2026)
Preparation is not an optional extra added to make a quote look bigger. It is the work that gives the tiled finish a suitable, stable and flat base. The correct build-up depends on whether the floor is screed, concrete, timber, already tiled, cracked, uneven or carrying movement between different substrates.
Indicative estimate from Paul's live 2026 price book. It is not a fixed quotation.
Paul’s practical take
When I look at a floor, ‘does it need levelling?’ is not the first question. I want to know what the floor is built from, whether there is movement, how flat it is, what is under the existing covering and whether different substrates meet in the same area. Levelling, boarding and decoupling solve different problems. I don’t want to specify one just because it is on a checklist.
Paul Finn, working tiler
Flatness and level
A floor can be flat without being level, or level without being flat. Large-format tiling chiefly needs the surface flat enough for the chosen tile.
Movement and transitions
Extensions, cracks, timber flex and changes of substrate may require strengthening, movement joints or a decoupling membrane.
What removal reveals
The true condition is sometimes hidden by old tiles or adhesive. A sensible estimate separates confirmed work from preparation that can only be known after strip-out.
What the estimator accounts for
It asks for the inputs that actually move the work instead of multiplying one headline rate by the room area.
- Existing substrate and condition
- Tile or adhesive removal
- Self-levelling compound
- Timber overboarding
- Decoupling and movement considerations
Why two similar-looking jobs price differently
The expensive failure is skipping preparation because the finished tiles hide it. A floor can look acceptable on day one and still crack, debond or show lipping later. Pricing the base separately makes clear which work is protecting the installation rather than pretending it is included for free.
Common questions
Is self-levelling always needed?
No. It is used when the substrate needs correcting for the proposed installation. The floor should be assessed rather than levelled by default.
Does a timber floor need overboarding?
Often it needs strengthening or a suitable tile-backer build-up, but the answer depends on the boards, joists, movement and height available.
What does a decoupling membrane do?
It helps manage differential movement between the substrate and tile finish. It is not a substitute for repairing an unsound floor.
Related guidance and real work
Check what preparation may be neededTile and subfloor preparationSelf-levelling floorsHow long a tiled floor lasts
Stop guessing from averages
Put your room, tile and preparation into the estimator and get a useful starting figure.