There's nothing like nasty water marks and damp patches on walls and ceilings to get househunters running for the hills. While scuffs and stains are part of the normal wear and tear of a house, some types of watermarks caused by damp, condensation or water accidents can prove incredibly stubborn to remove long after the root cause has been dealt with.

If walls or ceilings have water stains or other serious discoloration, the first step is to ensure that you have fixed the problem by stopping it at source, whether that's getting the plumber in to tackle a problematic shower or experts in to fix a leaky roof. Once you have the problem fixed you now have to deal with the lingering stain. This could mean a new coat of paint, but if stains are stubborn it may be necessary to coat them with a stain-killing primer to prevent them from bleeding through before you paint them. A number of products are on the market, specially designed to tackle these eyesores. Most are made from highly pigmented paint with more colour content that normal paint. Thompson's makes a quick-drying one-coat damp seal which is a good product for non-serious jobs - you can decorate after four hours. Price 7.70 for 250 ml in Atlantic Homecare. For small areas try Polycell's spray stain stop, which is touch-dry in 15 minutes,€12 for 250 ml. For more stubborn stains try Aquaseal's damp stain block which requires two coats and 24-hours drying time, €10.50 for 5 litres.

Another option is International Paints' stain block paint in brilliant white. €45.71 for 2.5 litres. International also has an anti-damp paint that according to the manufacturer can even be applied to damp surfaces and contains a fungicide to protect against mould growth. This won't cure a damp problem but can be applied to a stain that is still damp after the root cause has been fixed.