Avoid any problems with paint; DIY.

ONE of the downsides of DIY is that things don't always go to plan.

Unforeseen problems crop up often and dealing with them is often time consuming and frustrating, but it has to be done.

Like most DIY tasks, painting can be a bit of a minefield for beginners, but it basically boils down to a few simple rules of preparation and application - and a lot of common sense.

Here are some common painting problems and what you can do about them.

FLAKING

It's common for paint to flake with age, but if your paintwork isn't that old, there may be other causes, such as poor surface preparation.

Whatever you're painting, it must always be prepared, eg sanded, and cleaned thoroughly first to avoid a poor finish.

Alternatively, if you live in a period property that hasn't been decorated for years, flaking paint could be caused by distemper (an old-fashioned glue or sizebased type of paint). To test for distemper, wet the paint with water and wait to see if it peels away - distemper will. Get as much of it off as you can with water and a scraper, then seal the rest with a couple of coats of plaster sealer.

SEEING DOUBLE

If you can see the paint you've painted over through the paint you've recently applied, you've probably used the wrong undercoat or no undercoat at all. Other causes of this problem include brushing the paint out too much, thinning the paint too much and not stirring the paint adequately, which is especially important with oil-based paints because they separate.

DULL GLOSS

If your gloss isn't glossy enough, paint that's too thin or has been over brushed may, again, be the cause. On the other hand, it may be that you haven't allowed the gloss to dry properly between coats (unless you're using a quick-drying product, this can take a very long time) or that you've painted in a room that's too cold, which will slow down the drying process.

RUNS, WRINKLES AND HAIRLINE CRACKS

These occur when the paint is applied too thickly and isn't brushed out properly.

To solve the problem, leave the paint to dry for at least a week, then rub down with sandpaper and start again.

The same applies if your paint is blistering. This is usually caused by applying paint to a wet surface or to existing paint that's soft, old or peeling.

SPECKS IN YOUR PAINTWORK

It's easy to get dust and debris into paintwork, especially when using wood or metal paint. Avoid this by keeping your brush or roller clean and also the surface onto which you're painting.

Dust and debris will get into your paint pot, too, especially if you're working outside. You can get round this by putting a small amount of paint into a paint kettle and working from that, so all the paint isn't ruined if the kettle becomes contaminated.

If you're painting skirting boards, it's easy to pick up dust and debris from the floor below, so clean the floor thoroughly first and then cover with masking tape or a paint guard. Other tips include making sure your paint pot lid isn't dirty when you replace it and not wearing clothes that deposit lots of fluff near drying or wet paint. If there's debris in your paint pot, try scooping it out with a piece of plastic or stiff cardboard.

YELLOWING

Yellow stains can occur when you've painted over bare wood but haven't sealed the knots, allowing the resin in them to bleed through. Knot sealing is really quick and easy to do and shouldn't be overlooked - just use a couple of coats of knot-sealing solution, following the manufacturer's instructions.

Yellowing also commonly occurs on radiators, especially white or cream ones, if you don't use special heatresistant radiator paint.

Clear wood varnishes can yellow, too, so look out for ones that say they're non-yellowing.