Planning floors, tiling and screed

A floor is only as good as what is under it. Tiles on a flexing or uneven base crack, and laminate on a damp slab swells. Preparing the base, which may mean a new sand-and-cement screed, takes more care than the finish on top. The quantities are straightforward: the area plus an allowance for cuts.

This planner covers screed, tiles and laminate, which are the most common floor jobs.

Step 1: Measure and plan the layout

Measure the room in square metres and plan where the tiles or planks start, so the cut tiles at the edges are not slivers. Allow about 10% for cuts, and more for diagonal layouts.

Step 2: Level the base and screed if needed

A sand-and-cement screed levels a floor and covers underfloor heating pipes. The depth depends on whether it is bonded, unbonded or floating over insulation, and it needs time to dry, often a day per millimetre for the first 50 mm.

Step 3: Tiles, adhesive and grout

The tile materials calculator gives the tiles, the boxes, the adhesive and the grout. Wet areas such as showers need waterproofing (tanking) under the tiles. Use the right adhesive for the base and the tile size.

Step 4: Laminate flooring and underlay

Laminate is laid floating over an underlay on a flat, dry floor, with a 10 mm gap round the edges for expansion. Let the packs sit in the room for 48 hours first. A damp-proof membrane goes over a concrete floor.

Step 5: Trims and thresholds

Skirting, scotia and door bars finish the edges. Measure the perimeter less the doorways.

Before you start

• The type of floor structure: concrete or timber, and any underfloor heating.
• Moisture in a concrete floor, which must be low before laying.
• The height of the new floor at the doors, and the thresholds.
• Spare tiles or packs from the same batch.
• Dust and noise: plan where cutting will take place.

Mistakes that cost people money

• Laying tiles over a flexing timber floor without a stiff base.
• Laminate laid over a damp or uneven floor.
• No expansion gap round the edges of a floating floor.
• Not letting a screed dry before tiling or laying a floor.
• Ordering only the exact area with no allowance.

Frequently asked questions