Problems: After You've Finished Papering

Bubbles

Sometimes bubbles will disappear when the paste has dried out, so it's worth waiting a while before tackling them. If a bubble seems to be full of paste, (because you applied too much, or didn't smooth all the way to the edge), simply pierce the bubble with the sharp tip of a craft knife or scalpel and allow the excess paste to escape. Carefully sponge down the 'empty' bubble afterwards to clean any paste from the face of the paper. Sometimes bubbles are full of air - cut a small 'X' into the bubble, peel back the corners, and use a fine artists' brush to apply a little paste and smooth the bubble back down with a damp sponge.

Gaps at Seams

The paper has shrunk on drying, caused by the paste being too thin. If the paper is to be painted, you will probably be able to work cellulose filler into the gap with a finger. If the paper is patterned, find a matching coloured pencil and use this in the gap to help conceal it. Alternatively, hang a new length.

Brown Spots

Wire wool may have been left on the surface during preparation, or a nail or screw head left just below the wall surface could have rusted. A damp wall on which mould has developed is also a possibility.

Strip off the paper and prepare the wall properly - do not rub down with wire wool. Damp problems must be treated before redecorating. If the wall is prone to condensation, line it first with expanded polystyrene sheeting. Available in DIY superstores, this is thin polystyrene that comes in a roll and is hung like wallpaper. Lining paper is not needed over the polystyrene if you're going to use ordinary wallpaper, but some manufacturers recommend also applying lining before hanging vinyl or woodchip papers. Use the adhesive recommended by the manufacturer - usually their own brand.

Stained Seams

Poor preparation has meant that old size (sealant) remained on the wall. Wiping with a clean, damp rag may help but usually the only answer is to start again, making sure the walls are washed down with warm water to remove old adhesive and size.

Flattened Embossing

A paper with a relief pattern may have been flattened by:

• over-rigorous brushing when hanging
• running a seam roller down it

This can't be rectified - hang new paper.

Shiny Patches

Over-rigorous brushing when hanging is the cause. Rub over with a ball of white bread to lessen the effect.