Preparing Walls and Ceilings
Any professional painter will tell you that preparation is crucial to a good finish. It’s time-consuming and hard work stripping off old finishes – and even new, bare plaster needs priming – but your job will be far easier if you know what to do.
PAINTED OR WALLPAPERED SURFACES
- If repainting and existing paint is sound, wash with sugar soap and water.
- If papering, rub surface with a damp flexible sanding pad to remove the sheen and provide a key for new paint. Ideally, hang lining paper.
- If acrylic is peeling, strip back to a sound base. There may be an unstable layer of kalsomine underneath.
- If the acrylic is sound, wash and roughen the surface with sugar soap and water.
- If papering, use a wallpaper size.
Kalsomine – an obsolete, water-based paint – forms a chalky barrier which prevents paint or paper adhering to the wall.
- Scrub off with a rough cloth or a nylon pan scourer and water.
- If there is a thick coating, damp the whole area, then scrape with a wide stripping knife. Never scrape kalsomine without wetting; it makes too much mess.
- Coat any remaining kalsomine with an oil-based sealer/binder.
- Soften ordinary wallpaper with warm water and a little washing-up liquid.
- Add a handful of wallpaper paste to each bucket of water – it helps to hold the water on the wall.
- Use a scraper to lift off the paper.
- Roughen the surface with coarse abrasive paper before you wet it or use a steamer.
- If the paint is thick, you may have to score the surface with a wallpaper scorer.
- Never use a wire brush – if slivers of metal become embedded in the plaster, they will corrode and stain wall coverings.
Paint with a high lead content can cause lead poisoning. Most houses built before 1950 contain lead paint. If your house was built between 1950 and 1978, it may or may not contain lead paint. Houses built after 1978 will generally be entirely free of lead paint. See pages 65-67 for information on how to remove lead paint from your home.
Tip: Paint Strippers
Water-based paint strippers are a safe, non-irritant alternative to traditional chemical strippers. Suitable for wood, metal and stone, they will remove all kinds of paints, varnishes and waxes. Once stripped, consult your local council for how to dispose of lead- and solvent-based paints.
Vinyls, washables and wipe-clean papers
- Buy or hire a steam wallpaper stripper, especially if the wall is covered with layers of old paper. Score the surface first so that water can penetrate.
- Vinyls are easier to strip – the vinyl skin can be pulled from its backing, then the backing can be soaked and stripped.
- With some modern papers and vinyls (called easy-strip), the backing can be left on the wall as lining paper for the next wallcovering. This only works if the paper is well stuck. If there are any loose areas, strip the whole lot TILES, TEXTURES AND BRICKS Textured coatings
Thick coatings applied by brush or roller on ceilings and walls are difficult to remove.
- If you simply want to repaint the textured surface, lightly scrub it with a mild solution of sugar soap and water and allow to dry.
Expanded polystyrene ceiling tiles can be painted with acrylic, but never with gloss paint. To remove tiles, lever each one away from the surface and then scrape off the tile adhesive.
If tiles are to be painted, make sure they are clean and dry, then use a specialist tile paint. You cannot hang wallpaper over tiles so you may wish to remove them. Beware, this is hard work, and will necessitate replastering the wall.
Cork tiles cannot be painted over, though you may be able to cover them with lining paper and wallpaper.
- Prise each tile away from the wall with a wide stripping knife or a bolster chisel.
- To remove hard lumps of glue, follow the instructions for taking down expanded polystyrene tiles.
- Brush the bricks to remove dust.
- Paint interior bricks with acrylic primer then acrylic top coat or leave them unpainted.
Steam-stripping a ceiling
You can use a steam wallpaper stripper to remove old painted or washable wallpaper from a ceiling. Because you will be using the steaming plate above head level, take precautions to protect yourself from being splashed by very hot water. Wear a baseball cap or similar headgear, safety goggles, a longsleeved shirt and work gloves. Set up a work platform across the room, rather than trying to work from steps, so you can hold the steaming plate in front of you as you work across the ceiling strip by strip. Put down plenty of drop sheets, and let the scrapings fall to the floor.
Be warned, however; this is a messy and time-consuming job, and you may prefer to employ a plasterer to apply a skim coat of plaster over the old finish to create a smooth ceiling surface.
|Efflorescence||Damp can cause chemicals and salts in mortar or plaster to come to the surface and form a white fluff called efflorescence. Brush this off the wall thoroughly, then apply an alkali-resisting primer.|
|Stains||Cover stains made by tar deposits in a flue or rust marks on a wall, for instance, with an aluminum primer sealer or bleed sealer. This stops the slain from bleeding through the new paint.|
|Damp||Do not isolate damp by applying an impervious coating – this will simply cause it to move elsewhere, creating fresh problems. Find and cure the cause.|
|Brush away any loose or crumbling plaster from small holes and cracks and repair the area with an appropriate filler. Larger holes, gaps and cracks require more extensive treatment.|
|Uneven plaster||Level out slight irregularities with a skimming coat of surface plaster.|