Tiling and flooring take-off: working out the m² of floor tiles, wall tiles and skirting

This guide follows French practice: French standards (NF DTU), French regulations and French bill conventions. Most sources are in French.

The items of a tiling and flooring package, and their units

Floors, walls, trims and substrates: a tiling or floor finishes package brings together items of very different kinds. In a priced bill of quantities, you will generally find the following lines.

In France, workmanship is covered by NF DTU 52.1 for bedded floor tiling (February 2020) and NF DTU 52.2 for adhesive-fixed ceramic tiles and similar products (June 2022). These standards deal with substrates, joints, junctions and tolerances; they do not say how to measure. The method of measurement, the deductions and the content of each item come from the specification and the bill format.

Allow one item per finish, per format and per laying pattern: a 60 × 60 tile laid straight and the same tile laid diagonally take neither the same laying time nor produce the same waste, so they do not have the same rate.

Floor area, room by room

The floor is measured room by room, to the finished face of the walls, partitions and linings deducted: this is the area actually covered, the same as the ceiling area in a painting take-off. Wood flooring and resilient floor coverings are measured in exactly the same way. Measuring a whole flat in one go mixes finishes and makes checking impossible.

• The strip under the doors, as wide as the partition is thick, belongs to one of the two rooms, never to both. Note your choice and keep to it throughout.
• Under fitted units and in cupboards, the specification says whether the finish runs underneath. A kitchen standing on the tiles and tiling stopped at the face of the units do not give the same area.
• One room, one finish: when two finishes share a room (tiles in the entrance, wood flooring in the open-plan living room), draw the boundary where the drawing shows it.

What is deducted

From the gross area of the room, take off whatever does not receive the finish: shower tray, bath if the floor is not tiled underneath, level-access shower measured as a separate item, service ducts, columns, voids, plinths and steps. Small items, such as a pipe penetration, are often left in: the threshold below which nothing is deducted, where there is one, is set by the contract.

An exam paper of the French vocational certificate for tilers (CAP carreleur mosaïste, 2021) shows the approach: the shower room measures 9.79 m², the level-access shower 0.80 × 1.20 = 0.96 m², and the tiled area of the rest of the room is 9.79 − 0.96 = 8.83 m². The shower, with its fall and its waterproofing, has its own lines.

Skirting: the perimeter less the openings

The length of skirting starts from the room perimeter, but it is almost never equal to it. Take off:

• the width of every doorway and of every opening down to floor level (French window, sliding door);
• the lengths where wall tiling runs down to the floor, in a bathroom for instance;
• the lengths behind kitchen units or a bath, if the contract does not ask for them.

Conversely, a column or a duct in the room adds its perimeter. Tiled, timber and PVC skirtings are separate lines, as are matching skirting tiles and skirting cut from the floor tile.

Wall tiling: wall length × height

Wall tiling is measured like a wall: the length of wall covered, multiplied by the tiling height. That height changes from one area to another (full height in the shower, a fixed height above the bath or the worktop): one item per height, or at least one line per area.

In the same exam paper, the tiling of the shower is worked out as follows: (1.20 + 0.80 + 0.97 + 0.07) = 3.04 ml of wall, multiplied by the ceiling height, 2.50 m, giving 7.60 m². Openings are deducted over the tiling height only: a 0.80 m wide door in tiling 1.20 m high takes off 0.80 × 1.20 = 0.96 m², not the full height of the door.

Around the area, count separately whatever the bill pays separately: bath panel and boxing, corner and edge trims, flexible sealant at the junction with the sanitary fittings.

Waste, setting out and ordering

The take-off gives the area laid. That is what goes into the bill: waste belongs in the unit rate and in the order, not in the contract quantity. The waste allowance depends on the format, the laying pattern (diagonal laying needs more cuts), the shape of the rooms and the setting out; it has no universal value. The exam paper quoted sets 5% for the tiling of its shower: that is a given of the exercise, not a rule.

The order is then rounded up to whole boxes: in the same paper, 7.98 m² to be ordered in 1.50 m² packs gives 5.32 packs, i.e. 6 packs. For large formats, the setting-out plan fixes where the cuts and joints fall. Movement joints, which NF DTU 52.2 covers among the special details, are measured by the linear metre when the contract pays for them separately.

Worked example

A 2.40 × 2.00 m bathroom (ceiling height 2.50 m) and a 5.20 × 4.10 m living room. The specification requires the shower tray to be deducted, wall tiling full height in the shower and 1.20 m high elsewhere, and skirting by the linear metre (rules taken for the example).

Bathroom

The room perimeter is 2 × (2.40 + 2.00) = 8.80 ml; from it we take off the 2.10 ml of shower walls, already counted full height, and the 0.80 m door. No skirting: the wall tiling runs down to the floor.

Living room

Order (outside the take-off)

The waste allowances and the box size are taken for the example. The bill receives 3.72 m² and 21.32 m² of floors, 12.33 m² of wall tiling and 15.30 ml of skirting. Using the gross perimeter of the living room, we would have written 18.60 ml of skirting, 3.30 ml too much.

The most common mistakes

• The room perimeter carried over as skirting, doors and openings included.
• Skirting counted under wall tiling or behind units.
• The strip under the doors counted twice, or not at all.
• The shower tray, the bath or the level-access shower left in the floor area.
• A door taken off the wall tiling over its full height when the tiling stops at 1.20 m.
• Waste added to the bill quantity, then counted a second time in the rate.
• Formats and laying patterns mixed in a single item.

Doing it in Kotelys

In Kotelys, each finish becomes a type (“Tiles 60 × 60”, “Oak flooring”, “Wall tiles 1.20 m high”, “Skirting”): a name, a colour on the drawing, a total.

• Floors are drawn with the Area tool, room by room; a click and drag draws a rectangular room. Shower trays, ducts and voids are placed as deductions (S key, Shift+S to edit them). The area and the perimeter of each shape are displayed; the “Sides” box writes the length of each side, to check the dimensions.
• For skirting, the P key creates a length that follows the outline of the selected area. Put it in your “Skirting” type (right-click, “Move to this type”) or make it a new type (Shift+G), then place an opening at each doorway (O key): only the remaining length is counted.
• Wall tiling is drawn with the Length tool, with one height per type: “2.10 ml × 2.50 m = 5.25 m²”. Each opening takes its own height, or the full height of the tiling.
• A thickness given to a screed type gives its volume; threshold strips are counted with the Count tool.
• One zone per room or per flat, and the “Break down by zone” box of the reports splits every quantity. The take-off calculations write out every calculation, deductions in detail; the Excel workbook gives the summary and the object-by-object detail, perimeter included.

Kotelys does neither the setting out nor the waste: it measures the area laid, and the waste allowance and the number of boxes stay in your pricing.

Further reading: tiling and flooring take-off in Kotelys, and the other guides.

Sources

1. FFB, « Pose collée de céramiques pour les sols dans le neuf : l'essentiel du NF DTU 52.2 » (NF DTU 52.2, June 2022)
2. FFB, « Pose collée de céramiques en murs intérieurs dans le neuf : l'essentiel du NF DTU 52.2 » (junctions, movement joints)
3. FFB, « Revêtements de sols scellés et sous-couches : l'essentiel des NF DTU » (NF DTU 52.1, February 2020, laying skirting)
4. FFB, guide « Pose collée des revêtements céramiques de grand format et format oblong pour sols intérieurs » (setting out, cutting)
5. Éduscol STI, CAP carreleur mosaïste 2021, EP1 paper, marking elements (shower wall tiling, waste, area without the shower)

Thresholds and values described as “taken for the example” are not rules: those of your contract (specification, bill of quantities) always prevail.