September 14th, 2021 by Sarah Miles

Getting a really great decorating finish is as much about the standard of preparation as it is about how you apply the paint. However good a decorator you think you are, if you start out with walls that are cracked, bumpy, dirty, and littered with leftover bits from previous décor choices, you will never get a really good finish. It may seem like a bind but it’s all about the preparation, plus thorough prep will usually save you time on the painting, so all things work out even in the end.

As well as the obvious things like masking off skirting boards, moving furniture out of the way, and covering things up, one of the key tasks to attend to is preparing the surface of the wall so you have the best possible base for your paint. How you do this will depend on how the wall has been decorated previously.

In this article, we take a look at the 3 most common wall surfaces.

Wallpapered Walls

We’re starting with the most difficult as you will need to remove all traces of wallpaper before you can start painting (if you’re considering just painting over it, don’t. Not only will you always be able to see the joins, but it will also make the paper much more difficult to remove later if it’s got layers of paint on it).

The first step is, obviously, to remove the paper. There are a few different methods for doing this:

Scraping

Use a scraping tool to literally scrape it from the wall. This is ok for small areas but is labour intensive, messy, and time-consuming. If the previous paper is stuck on well and doesn’t peel off easily, you’re also likely to be left with lots of little scrappy bits on the wall which can take some removing.

Steaming

A steamer softens the wallpaper and melts the wallpaper paste underneath so that you can scrape it off more easily. This can be a good method to use but it can make the room very hot and steamy and saturate the wall, which will need to be allowed to dry thoroughly before you can progress.

Heat gun

Many won’t consider a heat gun as a tool for removing wallpaper, but it can be really effective when used on low heat. As with a steamer, it melts the paste behind the paper but doesn’t make it wet.

Once you have removed the wallpaper you can proceed to the general preparation steps.

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Painted Walls

Walls that have been painted before will take paint well but there are a few steps to take to deal with any remains from previously decorating and the general wear and tear that walls sustain over the years.

• Give any cracks and holes a wipe over to remove dust and fill them with a flexible filler. Allow to dry and then sand smooth
• Sand down any raised areas of the walls, such as drips from previous paint

You can now proceed to the general preparation steps.

Newly Plastered Walls

Walls that have just been plastered are the easiest to prepare because you’re starting with a brand new surface. They still require some work though.

1. Allow to dry out completely. Dry plaster will be a pale pink colour
2. Rub over the surface to remove any traces of dust
3. Prime the surface with a sealer. This seals the surface and stops it from soaking up excess paint.

You can now proceed to the general preparation steps.

General Preparation Steps

All steps above should have got you to the same point for proceeding. This is what you need to do next:

1. Sand the wall
   Not everyone chooses to do this, but it is a really good way of removing any last scraps of paper or bumps and it will create a textured surface that will hold the paint well (a freshly plastered wall probably doesn’t require this but it wouldn’t do any harm).
2. Clean the wall
   For a fresh wall, this may just require a wipe over with a cloth or brush but a wall that hasn’t been cleaned in a long time will benefit from a wash to remove dirt, dust, as well as grease and other contaminants. Sugar soap is good for this. Allow the wall to dry completely before you start painting.
3. Apply undercoat
   Rather than going straight in with your colour, a couple of layers of a neutral undercoat will provide a good base, allow the colour you are applying to be true (painting over a different colour can affect the result) and will reduce the amount of coloured paint needed (which will usually be more expensive than your undercoat paint).