Do I need primer to paint a room?

Not on walls that were painted before and are sound. Bare plaster needs a mist coat or a primer-sealer, stains need a stain-blocking primer, and glossy paint may need an adhesion primer. The paint's instructions decide.

How many roller sleeves do I need?

One frame and a sleeve for each paint. With a wall paint and a ceiling paint that is two sleeves, so neither has to be washed out between them.

What you need to paint a room: the complete checklist

To paint a room you need the paint, something to clean and repair the walls with, the tools to put the paint on, and sheets and safety kit to protect the room and yourself. Most of that list is the same for every room; whether you need a primer, and how much filler and caulk, depends on what the walls are like now.

The checklist

Item	Needed	What decides how much
Wall paint	For the walls	The wall area, the coats and the coverage on the tin
Ceiling paint	For the ceiling	The ceiling area, the coats and the coverage
Primer, sealer or mist coat	Depends on the walls	The surface and the paint’s instructions
Sugar soap or wall cleaner	Always	One container does a room
Filler	Depends on the walls	A small tub or a tube for a sound room, more where paint is flaking
Decorator’s caulk	Depends on the gaps	The size of the gaps; the tube says how far it goes
Abrasive paper or sanding sponges	Always	How much filling there is
Masking tape	Your choice	The edges you mask; rolls are commonly 25 m or 50 m
Dust sheets	Always	The floor area, and the furniture left in the room
Roller frame and sleeves	Always	One frame, a sleeve for each paint
Roller tray or scuttle	Always	One
Brush for cutting in	Always	One
Extension pole	For the ceiling	One
Filling knife and scraper	Always	One of each
Dust mask, eye protection and gloves	Always	A set for each person working

“Always” means every room, however good the walls look. Masking tape is your choice because a steady hand with a cutting-in brush replaces most of it.

What depends on the walls

Look at the walls before you buy. BuildBatch asks one question about them, and each answer changes the preparation lines:

Previously painted and sound. Usually no primer. Check the paint’s instructions for a strong colour change or a glossy surface.
New or bare plaster. A mist coat or a primer-sealer before the top coats. See painting new plaster.
Stains that show through. Find the cause first, then a stain-blocking primer on the patches.
Damp or mould. Fix the cause first. Paint will not cure either.
Flaking, powdery or glossy paint. More filler and abrasive, and possibly an adhesion primer.
Wallpaper or a textured coating. Identify the surface first; each needs its own preparation.

Older paint can contain lead, and textured coatings applied before 2000 can contain asbestos: do not sand or scrape a coating you are not sure about; get advice first.

Worked example

The example room is 4.2 m × 3.6 m × 2.4 m, with one door and one window, walls and ceiling previously painted and sound. At the example figures of 2 coats, 10 m² per litre, 10% extra and 2.5 L tins, the list reads:

Wall paint: 34.484 m² of wall, 7.586 L, so 4 × 2.5 L tins
Ceiling paint: 15.12 m² of ceiling, 3.326 L, so 2 × 2.5 L tins
Primer: not needed on sound paint
Sugar soap: one container, for about 49.6 m² of wall and ceiling
Filler: a small tub or a tube, once you have looked at the walls
Caulk and masking tape: about 41.4 m of edges, where the walls meet the skirting, the ceiling and the frames. Masking the lot is one 50 m roll or two 25 m rolls
Dust sheets: enough to cover a 15.12 m² floor and the furniture
Roller: one frame and two sleeves, one for each paint
Tray, cutting-in brush, extension pole, filling knife, scraper, dust mask, eye protection and gloves: one of each

The tins come from the example figures; the coverage on your own tin replaces them. For how litres become tins, and why mixing tin sizes can leave less over, see how much paint do I need?

Easy to forget

The second roller sleeve, when the walls and the ceiling are different paints.
The extension pole, when you are doing the ceiling.
Something to stir with and to lever the lids off.
A bucket, a sponge and clean cloths for washing down.

Do it with BuildBatch

Open the Room Refresh Batch with paint chosen, type the room and answer the question about the walls. You get the paint in whole tins and every other line above, each marked Need or Check first, with the reason it is there.

What this guide does not cover

Painting woodwork such as skirting, doors and frames, which takes its own paint and brushes. Removing wallpaper. Exterior walls. Stairwells and high ceilings, which need proper access equipment rather than an extension pole. Diagnosing damp.