Laminate flooring: how much to buy and how to prepare

Measure each room separately, including alcoves and the space inside door frames where the floor continues. Multiply length × width, add the alcoves, and subtract only what is permanently built in.

Then add the cutting waste: around 7% for a straight layout in a regular room, 10–12% for diagonal layouts, rooms with many corners or very short rows. Divide by the coverage per pack and round up. Buying one spare pack from the same batch is worthwhile — it makes a future repair invisible.

Floating floors are forgiving, but not of everything. Before ordering, check three things:

• Flatness: lay a long straightedge (2 m) in several directions. Most manufacturers allow only a few millimetres of deviation over 1–2 m; high spots are ground off, hollows filled with levelling compound.
• Moisture: new screed must be dry. In some countries, moisture is measured with the calcium carbide (CM) method; the maximum values depend on the screed type and the flooring.
• Firmness: creaking or flexing wooden floorboards should be screwed down or overlaid with boards before the new floor goes on.

The underlay evens out small irregularities and reduces footstep noise. Some floors have it pre-attached; adding a second one usually voids the warranty.

On concrete, screed or any mineral substrate, a vapour barrier (typically a PE film with overlapped and taped joints, or an underlay with integrated barrier) protects the floor from residual moisture rising from below. Over underfloor heating, choose a flooring and underlay approved for it and keep the combined thermal resistance within the manufacturer's limit.

• Store the unopened packs flat in the room for about 48 hours before fitting, at normal room temperature.
• Lay the boards parallel to the main light source, or along the longest wall in narrow rooms.
• Measure the room width before starting so the last row isn't a thin sliver; adjust the width of the first row if needed.
• Stagger the end joints between rows by the minimum distance the manufacturer specifies, so the joints don't line up.
• Leave an expansion gap around the edges and at every fixed obstacle (pipes, door frames, thresholds). Its width is given in the instructions — it is hidden later by the skirting.

Skirting is bought by the running metre: the room perimeter minus the door openings, plus around 5% for joints and mitred corners. Large rooms or long corridors may need expansion profiles at intervals specified by the manufacturer, and doorways usually need a transition strip between rooms.

Check that doors will still open over the new floor plus underlay — trimming a door is easier before the floor is in.

• Tape measure, pencil, square and a long straightedge
• Fine-toothed saw or laminate cutter, jigsaw for notches
• Tapping block, pull bar and a rubber mallet
• Spacers for the expansion gap
• Utility knife and tape for the underlay and vapour barrier