Painting walls yourself, step by step

Check before you start

Before painting a wall, check whether you are allowed to. If you rent, the lease and your landlord's consent come first, and you should go in knowing you may be asked to restore the original finish when you leave. Then look at the wall itself. If there is mould, or stains spreading from damp, painting over it only hides it until it comes back through. Deal with the moisture and mould at the source first. If you plan to paint over wallpaper, the type of paper matters. Coated wallpaper may not hold paint well, so check the paint manufacturer's guidance on whether a special primer is needed.

How much to buy

Paint tins usually state how much area one tin covers. Multiply the area to be painted by the number of coats and divide by that figure to get a rough quantity. For wall area, multiply each wall's width by the ceiling height, add them up and subtract doors and windows. If that is tedious, an area calculator does it for you. Absorbent walls or big colour changes can use more, so buy a little extra; bear in mind that the same colour bought later may come out very slightly different.

• Work out width × height for each wall and add them
• Subtract doors and windows
• Multiply by the number of coats, usually two
• Divide by the coverage stated on the tin

Kit and protection

A large share of the job is preparation before any paint goes on. Move furniture to the middle of the room or out of it, and cover the floor and furniture with plastic sheeting or dust sheets. Mask the edges of anything you are not painting, such as skirting, window frames, socket covers and switches. Removing socket and switch plates gives a cleaner finish, and it is safest to switch off the breaker when you do. Have a roller for large areas, a small brush for corners and edges, a tray to pour paint into, a stable stepladder, gloves and safety glasses.

Surface preparation decides the result

For paint to stay put, the wall needs to be clean, dry and smooth. Wipe off dust with a dry cloth and grease near the kitchen with a cloth and mild detergent, then let it dry fully. Fill nail holes and small dents with filler and sand lightly once dry. If you are going from a dark colour to a light one, painting over a glossy surface, or have a lot of fresh filler, a coat of primer first gives an even colour and can save you a coat. Skip this stage and stains may show through or the paint may start lifting a few months later.

The painting order

Work from top to bottom and from edges to open areas. If you are doing the ceiling, it goes first and the walls after. On each wall, first brush a band along the corners and the taped edges, then fill in the large area with the roller. Rather than loading the roller heavily, roll it evenly in the tray, spread the paint over a section in overlapping directions, and finish with light strokes in one vertical direction to reduce marks. Finish a whole wall without stopping, so you do not get a visible line where wet paint meets dry.

• Ceiling, then walls, then frames and trim
• Brush the edges first, roll the open areas after
• Finish each wall without a break
• Make the final roller strokes in one direction

Two coats, and let them dry

A single thick coat runs, takes ages to dry and leaves an uneven surface. One thin coat, fully dried, followed by a second gives a more even colour and a tougher finish. The wait before recoating depends on the paint, the temperature and the humidity, so follow the manufacturer's instructions on the tin. Cold or humid days take longer. Pull masking tape off slowly at an angle before the final coat has fully cured and you get a clean edge. Leave it until fully hard and the paint may tear away with the tape.

Ventilation and clean-up

Even water-based interior paint smells during the job and for a while after, so keep windows open and ventilate well. If you feel dizzy or get a headache, stop and get some fresh air. Young children and pets are better off elsewhere until the smell clears. Tools used with water-based paint can be washed in water before the paint dries and reused. Do not pour leftover paint or paint-laden water down the sink or toilet. Disposal rules, such as letting small amounts harden first, vary by area, so check your local council's guidance. Keeping a little leftover paint is handy for touching up small marks later.