How to Take Off Painting and Decorating Work

The trade that is always priced last and always late

Decorating is the last trade on site and the first one to absorb everybody else's problems. Fill a bad joint and the painter will hide it, or fail to. Fit a door badly and the painter will be blamed for the shadow. It is also the cheapest trade per square metre, which is why it is estimated in a hurry.

That hurry is a mistake, because decorating is the only trade the client sees every day for the rest of the building's life. A paint system that fails at year three costs more in reputation than the whole decorating budget.

This guide covers the measurement, the specification, and the practical allowances that turn a rate per square metre into a number that survives contact with a real building.

Measure surfaces, not rooms

The quantity for decorating is the area of every surface to be coated, measured separately because each has a different rate.

A quick check for a room: perimeter x height, less 2 m² per door and 1.5 m² per window, less half the opening area again if you are deducting but still painting the reveals. Many estimators deduct the opening and forget the reveals, which is a small understatement that repeats in every room.

The ceiling multiplier that saves an hour

Walls and ceilings are usually painted the same colour in the same system, so on domestic work you can measure the floor area once and derive both:

Wall area is roughly 2.2 to 2.5 times the floor area for a room of normal proportions with a 2.4 m ceiling and one or two openings. Add the ceiling itself at 1.0 times the floor area.

So a 20 m² room is about 44 to 50 m² of walls plus 20 m² of ceiling, roughly 65 to 70 m² of paint surface. That rule breaks down in a room with a high ceiling, a bay or many openings, which is why it is a check and not a method.

A worked example

A three bedroom house, 95 m² of floor area, walls and ceilings in emulsion, woodwork in satin, plus external masonry to two elevations.

Internal:

External:

That is the quantity. The specification decides the rest.

Specification: the four decisions that set the price

The system. Two coats of emulsion over a mist coat is the minimum. Three coats, or a primer plus two, is what a colour change or a patchy substrate needs.

The paint quality. A trade vinyl matt and a premium washable matt differ in price by two or three times, and in durability by more. On a rental or a hallway, the difference is worth paying for.

The substrate condition. New plaster absorbs, previously painted surfaces may be silk or contaminated, and distemper or old lime wash will not accept modern paint without removal. Preparation is 40 to 70 percent of decorating labour and it is the part clients want to cut.

The finish. Matt, silk, eggshell, satinwood, gloss, each with different opacity and different rates. Dark colours over light need more coats than the coverage figure suggests.

Preparation, and why the labour estimate lives here

Filling, sanding, caulking, masking, protecting, dusting. On a refurbishment, half the decorating hours are these tasks, and they cannot be compressed without the finish showing it.

A practical allowance per room, for a standard refurbishment:

On new plaster the preparation is different but not smaller: a mist coat, filling of any pinholes, and sanding between coats.

Coverage, tins and the arithmetic of buying paint

A litre of emulsion covers 10 to 14 m² per coat on a sealed surface, and less on new or absorbent plaster. Gloss and satin cover 12 to 16 m² per litre.

For 303 m² of emulsion in two coats at 12 m² per litre per coat: 303 x 2 / 12 = 50.5 litres. Tins come in 2.5, 5 and 10 litre sizes, so this is five 10 litre tins or a mix, and there is always a part tin left.

Three buying decisions matter:

Productivity, by surface

For one painter on domestic work:

|---|---|

SurfacePer day
Walls, emulsion, two coats40 to 60 m²
Ceilings, emulsion, two coats30 to 45 m²
Woodwork, satin, prepared and two coats8 to 15 m²
Doors, both faces and edges3 to 5
External masonry, two coats30 to 45 m²

Woodwork is the slowest per square metre and the most sensitive to preparation. A door that is stripped, filled, sanded and given three coats is a day's work on its own, which is why a house full of original doors can cost more to paint than to replace with cheap new ones, and still be the better decision.

Exterior work and the weather

External painting is governed by temperature and moisture. Most systems need above 10 degrees and a dry substrate, and drying times extend sharply in cold conditions.

Two consequences. External work scheduled in winter will either be delayed or done badly, and the estimate should name the season. And access is a cost: two elevations at 5.6 m need a tower or scaffold, and a full house needs a scaffold that stays for the duration.

Colour changes and the coat that goes missing

A change from a dark colour to a light one needs an extra coat, sometimes two. A change from a strong red to a white can need three. The coverage figure on the tin assumes a similar colour underneath.

On a whole house repaint where the client has chosen a pale palette over the previous owner's stronger one, add 20 percent to the paint quantity and 10 percent to the labour. It is a predictable cost and it is a common source of argument when it appears as a variation.

Common errors in decorating estimates

  1. Measuring walls without adding reveals after deducting openings
  2. Pricing one coat when the specification needs two plus a primer
  3. Ignoring preparation, which is the largest single labour element
  4. Not allowing for a colour change
  5. No access allowance for external work
  6. Woodwork measured as if it were a flat surface
  7. Forgetting ceilings in rooms where they are painted white and walls are coloured
  8. No allowance for protecting floors and furniture on an occupied job

Wallpaper, and the roll arithmetic

Wallpaper is measured by roll, and the roll count depends on the pattern repeat. That single number changes the order more than the area does.

A standard roll covers about 5.2 m², but that figure assumes no pattern matching. A pattern with a 640 mm repeat and a 530 mm wide roll loses a length on every drop in a room with a 2.6 m ceiling, because each drop must start at a matching point rather than at the top edge.

The practical method is to count drops rather than area. Divide the room perimeter by the roll width to get the number of drops, then divide the wall height plus the pattern repeat allowance into the roll length to get drops per roll. On a room with a large repeat, expect 30 to 40 percent more rolls than the area suggests.

Lining paper is a separate line, and on a wall that is being repaired or has been painted, it is what makes the difference between a flat finish and a textural record of every patch.

White lead, distemper and the old substrates

On older buildings the substrate can decide the whole job. Distemper and lime wash cannot take a modern acrylic without removal, and removal means washing and priming, which is a week of work in a hallway.

Gloss over a friable surface will lift. Emulsion over grease or nicotine will crawl and stain through. A stabilising solution is cheaper than the third coat of stain block, and both can be needed.

The estimating habit that works is a two minute test: rub a damp cloth on a hidden patch. If it comes away chalky, the surface is distemper or a weak emulsion and the system has to change. That test is worth more than any coverage table.

Handover, durability and the touch up kit

A decorating job is finished when the client can live with it, not when the painter leaves. Two small items make that happen and both cost almost nothing.

A labelled tin of each colour, with the sheen and the batch written on the lid. And a small kit of filler, the right sandpaper and a brush, explained to the client in two minutes.

On a rental or a commercial property, that two minutes saves a call out charge in month three, and it is the sort of detail that gets a decorator invited back.

Frequently asked questions

How much paint for a room? For a 20 m² room, roughly 8 to 10 litres of emulsion for two coats on walls and ceiling, plus a litre or two for woodwork.

How many square metres does a painter do a day? 40 to 60 m² of walls in two coats, 30 to 45 m² of ceiling, and far less on woodwork.

Do I need a mist coat on new plaster? Yes. Thinned emulsion as a first coat seals the plaster and stops the following coats from being absorbed unevenly.

How many coats over a dark colour? Two to three on top of a primer, and the primer is what makes the difference to how many top coats you need.

Is cheap paint a false economy? Usually yes. Coverage is lower, opacity is worse, and durability on high traffic surfaces is much lower. The labour costs the same either way.

Should ceilings be painted before walls? Yes, and before the floor finish goes down. A ceiling painted last means protecting a finished floor for no reason.

Cost it in FRELUX

The FRELUX decorating calculator measures walls, ceilings, woodwork and external surfaces, applies the coat system and coverage you specify, and prices paint, preparation and labour from your local price book.

Gloss to metalwork15 to 25 m²