When painting with either gloss or emulsion paint, there are several problems which can occur, especially if you do not prepare the surface to be painted properly. Here we take a look at the most common problems and show how to avoid or fix them.
Paint will flake (lift off) if the base surface is not keyed properly. It may be either too chalky or too smooth. Painting emulsion on top of gloss can result in flaking if the gloss is not rubbed down. If flaking occurs, strip the whole area, clean and rub down, and then repaint.
Blistering is caused when air or moisture trapped under the paint layer expands with heat. Resin escaping from wood can also cause blistering. You will need to strip back the effected area, wait for the surface to dry thoroughly and then repaint.
Sometimes appears in oil-based paints. Usually caused by applying a second coat before the solvent has evaporated properly from the first coat, but also can be caused by applying paint too thickly. You will need to strip the paint and re-apply, leaving the recommended drying time between coats.
Matt patches in Gloss Paint
This problem can appear when gloss is applied to wood or another porous surface without first applying a primer. The gloss sinks into the wood, etc, and leaves patches of the surface with a matt finish. Further coats will usually not solve this problem. Strip the area and apply the correct primer before repainting.
Staining on Paint
Generally only effects emulsion, this problem occurs when a stain is painted over and then gradually bleeds through the paint surface. This can be fixed by either applying a stain-sealer before painting or, if you have already applied a coat, waiting for the first coat of paint to dry and applying a stain-sealer before the second coat.
Usually appears when incompatible paints are used together or when a second coat has been applied over a still wet first coat. Crazing looks like it sounds, tiny cracks similar in appearance to crazy paving. Leave the paint to dry completely, then rub it down with a sanding block, etc, before repainting the smoothed surface.
Only effects paint on wood, bleeding happens when the knots in a piece of wood have not been treated. Normal heat in your house will cause the resin in the knots to seep out and stain the paint. Knots in wood should always be treated with a sealer (known as knotting) before any paint is applied. If you have already painted, strip back the damaged area before applying the sealer and repainting.
Runs occur when paint has been applied too thickly (runs can appear in both oil-based and water-based paint). Leave the paint to dry and then scrape off the runs with a wide-bladed scraper. Rub down the effected area until it is completely smooth and then repaint (with less paint on your brush/roller).
Colour Showing Through
Can occur when a lighter paint is applied over a dark colour. In a situation where you will be painting over dark paint, always apply an undercoat. Undercoat is designed to cover a multitude of sins, whereas emulsion is not.
Appears when dirt or grit has been picked up on your brush or roller, or when it has gotten into the paint tin. If the brush is the only thing that has picked up the grit, clean it, then wipe the effected area on the wall and repaint. If you can see a lot of grit in the paint tin, you will need to strain the paint through a nylon stocking or a purpose made paint strainer.