To calculate how much paint you need, there are a few simple things you need to know:
Wall/ceiling area (height x width of the wall).
Coverage rate of the paint you are using (on the can).
How many coats you need (on the can).
For the wall/ceiling area, simply measure the width and height, and multiply them together. E.g. for a wall of 3m x 2.4m, the area is 7.2m² (3 x 2.4).
Then, check the coverage rate on the paint can. This will vary from product to product.
The coverage rate is per coat, e.g. 12m²/L. So one litre would be sufficient for one coat of a 7.2m² wall.
Finally, how many coats do you need? This information will also appear on the can label. For the example product and wall mentioned above, if it is a two-coat product you would need 2L for the project (2 coats x 7.2m² = 14.4m². If coverage is 12m²/L you would need 2L).
Protect unpainted surfaces and furniture by removing all furniture from the room.
Lay down a proper drop sheet to protect your floors. Try not to use old sheets as paint will often soak through. Mask skirting boards, window trim and electrical switches with painter’s tape.
If painting the ceiling, tape around light fittings and any vents.
If your walls or ceiling have mould, you will need to remove the mould with Selleys® Rapid Mould Killer™.
Scrub with a scouring pad and bleach solution (1 part bleach to 3 parts water).
Leave the solution on the surface for 15 minutes then wash with clean water and wipe dry.
Several applications may be necessary to remove stubborn mould blooms.
Once the mould has been removed and the surface is clean, dry and free from dust, oils and grease, you can paint without an undercoat.