How To Prepare Walls For Decorating

If you are planning to decorate your walls on your own, the first thing you need to do is prepare the walls for painting and wallpapering. It’s only if the walls are well prepared will you get a better finish after decorating your walls. Basically the wall’s preparation depends on its existing finish and construction.

This means you not only have to remove all the old paint and wallpaper, but also fill up any cracks and holes to ensure all surfaces are smooth, dry and clean. While it’s possible to paint over good condition emulsion painted surfaces, do strip back or sand off peeling paint.

The ceiling and any woodwork like door and window frames has to be prepared and painted or wallpapered before starting on the walls. Remove all the furniture from the room before you start preparing your walls. However if removing furniture is not feasible, you can at least protect the furniture and flooring with drop cloths against splattering paint and accidents.

Safety first

It’s important that you wear a dust mask and safety goggles to protect your eyes from fumes of paint and lead in old paint. In fact, if the paint has lead, it’s better to use a specially formulated liquid sander.

You have to prepare your walls by first washing all wall surfaces and then sanding it down. While you need to primer the walls before painting, it’s not necessary in case of wallpapering.

Washing wall surfaces

The walls have to be dusted and cleaned using a towel or vacuum cleaner. Then give it a wash as the less dirt and grime there are on the walls, the better the final paint job becomes. Its better using sugar soap as it effectively removes children’s drawings, nicotine stains, grease and finger marks from walls. Sugar soaps come in dissolvable powder or as a pre mixed liquid. However you need to wear safety goggles and gloves when you use it as it can irritate your skin.

Sugar soap is easy to use. Use an old but clean paintbrush or sponge to work it into the surface, leave it for a few minutes and then rinse off using clean tap water and a sponge. In case of older houses, there may be some distemper which readily rubs off as you wash the surface. Do not attempt painting or applying wallpaper over it as it doesn’t work. Instead, wash and scrape off as much of it as possible and then seal with a stabilizing solution.

Sanding down the walls

Sanding creates an even and smooth foundation for an improved end look and also gives a slight roughness which helps primer or paint adhere to. Sanding should be done using a smaller grade of paper and chosen based on the finish you are looking for. A 70 grade paper easily removes excess debris to leave a rough surface while a higher grade paper gives a finer finish. Generally a 70 grade paper is best for preparing walls for decoration.

The best way to sand is by wrapping the sandpaper around a sanding block and then sanding the surface in a circular motion to cover all areas. If the area you are smoothing is rough, run your hand over the area to check it’s smoothness and if it matches the rest of the area. If you are sanding wood work use a lower grade sandpaper and end with a higher one, working in the direction of the grain. This gives a smooth finish to paint over.

As sanding produces lots of dust, a dust mask and eye protection is a must, with lots of ventilation. Moreover, once you are done, you need to dust down the entire sanded surface from the ceiling to the floor and then vacuum to prevent particles from sticking to the freshly painted surfaces.

Previously painted surfaces

There’s no need of any sealing process while painting over previously painted walls or ceilings it’s sound. However you may require additional coats of paint to make a significant colour change.

Paint is a bit problematic to deal with it as different paints were used previously. So you need to first find out if the paint non-soluble and soundly bounded to the wall. You can check by dampening and then holding a clean sponge or cloth against the paint surface for 15-30 seconds.

If lots of paint gets transferred upon rubbing the area it means the paint is water soluble and has to be removed. However if only little paint gets transferred to the sponge, you can safely wallpaper the surface.

You need to use lots of water, cloth and effort to remove water soluble paints. As it’s a messy job, make sure you place some old sheets or newspapers on the floor before starting. Make sure the walls are not over soaked with water as it can damage some plasters and you need to wait till the wall dries out to start wallpapering.

In case the paint isn’t water soluble, look for signs of paint flaking off. If there is not much flaking of glossy and semi-gloss paint, just lightly sand it to a dull surface for the wallpaper paste.


Priming is not necessary on good condition walls which had been painted before; washing and light sanding is enough. However you may need a specialist primer if the surface has nicotine stains and if the wall was freshly plastered, before painting the final coat of paint.

Priming reduces the number of coats needed for porous surfaces by preventing the top coat from getting absorbed. In case of non-porous shiny surfaces; priming gives the surface something for paint to stick on. However different surfaces need different primers so follow instructions to choose the right one.

Of course, the colour should relate to your final colour too. Primer is applied just like you’d apply normal emulsion paint with a brush or roller. Let the paint thoroughly dry, and work in sections. There are various types of primers for you to choose form as required like wood, metal, radiator, and multi-purpose primers, plastic sealers and specific surface primers.

Stripping wallpaper

If you plant to decorate your walls with fresh wallpaper, you need to do the preliminary work of clearing as much furniture as needed or covering them with dust sheets. Stripping wallpaper is made easier if you first soak the wallpaper with hot water and if you score and cut the paper first with the blade of stripping knife.

Using wallpaper stripper solution

You can also remove wallpaper using a specially formulated wallpaper stripping solution instead of steaming. You have to first run an orbital scorer over the paper without damaging the plaster behind.

Add some liquid detergent and a handful of wallpaper paste to a bucket of hot water to thicken it. Now wet and soak a few square meters of the wall with a large sponge for at least five minutes and then slide a wide stripping knife edge under the paper. If it comes away in large sections, it’s ready to strip if not, you’ll have to use a steam or wallpaper stripper.

While using the stripper pad, hold it under a wallpaper section till it appears damp then move it to the next section while pulling the damp paper off below. Loosen all stubborn areas using a stripping knife from bottom to top, making sure the knife doesn’t damage the plasterboard or plaster.

Freshly plastered walls

Use a dilute mixture of PVA following manufacturer’s instructions or a mix of 1:1 water and emulsion to seal bare plaster and prevent the rapid absorption of emulsion paint layers while painting.

Preparing walls for wallpapering based on wall types

New plasterboard

You needn’t do much preparation for new plasterboard walls. Check the joints between the plasterboard pieces to make sure they are filled. Applying a few coats of dry wall primer before wallpapering seals the surface well and makes subsequent removal of the wallpaper easier.

Old plasterboard

Check for cracks, pits and bumps on the wall surfaces and repair them as mentioned earlier. Then apply a few coats of dry wall primer.

New plasterwork

Don’t hurry to wallpaper a newly plastered wall as it needs time to dry out, typically 4 weeks. This however depends on various factors like the plaster thickness and room humidity which is why it’s better asking the plasterer for recommendations. While new plasterwork is usually fine, it’s better to check for hollows or bumps on the walls and rub any high points and fill all dips.

Old plasterwork

Check and repair any loose plaster and small cracks by applying a coat of plaster sealer. If the wall is too damaged in small areas, you need to rack out and re-plaster the areas. Sometimes very old plaster may get very powdery with time; if that’s the case; its better striping off the old plaster and re-plastering the entire wall.

If you are apprehensive about wallpapering particular surfaces, you can test the surfaces by pasting 3 small strips of wallpaper and leaving it for 3 days on different parts of the wall. If they are firmly attached, you may start wallpapering the wall but if they come off the old surface, it means the wall needs more preparation.


All cracks in the walls have to be filled before painting or wallpapering by first using a filing knife to remove loose material. Then press the filler into the crack and smoothen off the surplus using a blade and an abrasive paper till the repair is flush with the surface. Then wash the surface with sugar soap to ensure the surface is free of dirt and grease for decoration.

Even all the existing holes in the walls like holes of picture nails have to be filled during wall preparation. Of course, if you plan to reuse the same position for perhaps shelf brackets, then you needn’t fill the holes. You can use a matchstick to mark the holes while wallpapering and then puncture the wallpaper with the matchstick after the strip is hung.

Types of fillers

There are three types of fillers you can use for different jobs.

1. In case of cracks between edges like between walls, ceiling walls and skirting, decorator filler or caulk is a better choice. It’s easy to use as it’s applied with a gun applicator to prevent future cracking.

Cut the end of the filler with a sharp knife and run the nozzle along the line of the crack while squeezing gently. Try not to get too much on and run your finger on the filler to force it into the cracks. Wipe off excess using a damp cloth. As this filler doesn’t sand well, it’s better getting a nice and clean smooth finish before letting it dry.

2. A general purpose, lightweight filler is a better option for filling holes and cracks. They are easy to apply, quickly to dry, doesn’t shrink into the hole while drying up and is easy to sand. It’s applied using a flexible scraper and fills most holes and cracks with one fill. Sand off any excess using medium sandpaper.

3. While you can use a lightweight filler to fill wood, its better using a two-pack wood filler as it gives a tougher finish. These two packs come with a large tub of filler and a smaller tub of hardener which have to be mixed together and used immediately as it hardens quickly.

Avoid applying extra filler as it’s not as easy to sand as lightweight filler but can be sanded with some effort using a medium grade sandpaper. Moreover, as it comes in natural wood colour it proves helpful while filling wood before varnishing as it blends well.

Materials and tools needed

Here is a list of tools and materials you’ll need to prepare your walls for decoration.

  • Caulk for filling crevices
  • Claw hammer for removing nails and picture hangers
  • Clean rags to clean up after a paint job.
  • Drop cloths to protect your floors and furniture
  • Galvanized nails to pierce and store caulk tubes
  • Gloves preferably rubber, latex or non-latex for protection from volatile chemicals
  • Masking tape to hold down drop cloths
  • Paint hat to keep paint off your hair and eyes
  • Paint scrapers to remove old paint
  • Patching or filler compound for repairing cracks and holes
  • Razor blades to clean paint from glass
  • Mask for protection from fumes of paint, stripper and dust
  • Sandpaper in coarse, medium and fine grades
  • Scarper or putty knife for applying compound or scraping paint
  • Tack rags for picking up paint dust and scrapings
  • Vacuum cleaner to remove dust
  • Wall cleaner and sponge to clean surfaces
  • Primer

While it’s not an easy job preparing your walls for decoration, it’s worth all the effort you put into it as it gives good results. Remember, the more prepared the walls are, the better the results!

How To Prepare Walls For Decorating Video

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About the author

Vladimir ShlykovVladimir Shlykov

Chief editor at Kitchen Improvements, Energy Efficiency, Bath and Shower niches expert at since 2009.