Wallpapering - Surface Preparation

As with all types of decorating, it is important to spend time in preparation, thorough preparation will make the job easier and ensure a satisfactory finish - just because wallpaper covers the wall does not mean that it will hide faults in them.

Before wallpapering:

• The ceiling should be finished.
• Any coving, picture or dado rails fitted and finished.
• All woodwork (frames, skirting board etc), should be fully painted or varnished.

While holes in the walls (including picture hook nails) should be filled during wall preparation, if it is intended that fixing positions (for shelves etc) should be reused, do not fill these and when you come to hanging the wall paper, put matchsticks in the holes so that they will puncture the wallpaper - this will give you the positions.

The preparation of the walls will depend upon the existing finish and type of wall.

Existing finishes:

• Wallpaper:
  Existing wallpaper should always be removed as described on our 'wallpaper stripping' page. Make sure that all adhesive residue is removed from the wall surface. In times past, people did wallpaper on top of existing wallpaper but this never gives a very good finish.
• Paint:
  Check to see if the paint is both non-water soluble and soundly bonded to the wall underneath. In older houses, whitewash or distemper may have been used and these are unsuitable for wallpapering onto, pay particular attention to areas at the top of the walls, near the ceiling where areas above a picture rail may have been distempered.
  To test if the paint is water soluble, dampen a sponge or cloth and hold it against the paint surface for about 15 to 30 seconds. If then rubbing the sponge on the paint removes a large amount of the wall paint, then the paint will need to be removed, a slight transfer of the paint colour to the sponge indicates that it should be all right for paperhanging.
  To remove most water soluble paints just requires cloths, plenty of water, and a lot of effort - it can be messy - don't over soak the wall as this can damage some plasters and the wall will need to dry out before it will be possible to hang your wallpaper.
  Check if the paint is soundly bonded to the wall by looking for signs of flaking paint.
  Glossy and semi-gloss paint should be lightly sanded to dull the surface.

Type of wall:

• New plasterboard:
  New plasterboard needs little preparation but make sure that any filling of joints has been completed and the filler allowed sufficient time for curing. Before hanging wallpaper, apply at least a couple of coats of dry wall primer.
• Old plasterboard:
  Check for, and rectify any cracks, pits and bumps as described on our page for repairing plasterboard. Apply at least a couple of coats of dry wall primer.
• New plasterwork:
  Don't be in too much of a rush to hang wall paper on new plasterwork, it should be given time to dry out, typically 4 weeks is a minimum period but depends, among other things, upon the thickness of plaster and the humidity in the room - check with your plasterer for their recommendation.
  Check for any bumps and hollows, generally new plasterwork will be fine but it pays to check. Rub down any high points.
  Finally the surface will need to be 'sized'. This can be done either using 'size', or a dilute mixture of wallpaper adhesive - most packets give the details. Ideally the adhesive should contain a fungicide (most do), this is particularly important for hanging vinyl wallpapers.
  
• Old plasterwork:
  Check for, and rectify any cracks, and loose plaster as described on our page for repairing plaster.
  Old plaster can become very powdery (often referred to as 'blown'), small areas may be overcome by applying a coat of plaster sealer, however when it has become too bad in small areas it can be racked out and replastered. Where a whole wall (or walls) is 'blown', it is more time/cost effective to replaster the whole wall.
  Pay special attention to cracks around door and window frames and along skirting boards, rake out any cracks and fill with a flexible decorator's sealant.
  Finally the surface will need to be 'sized'. This can be done either using 'size', or a dilute mixture of wallpaper adhesive - most packets give the details. Ideally the adhesive should contain a fungicide (most do), this is particularly important for hanging vinyl wallpapers.

If there is any doubt about the suitability of wallpapering a particular type of surface, test it by fixing about 3 small areas of wallpaper using the intended adhesive to different areas and leave for about 3 days.