Maintaining My Home

the yellowing of alkyd (oil-based) enamels is a well-known and well-documented effect that is irreversible. It generally applies to older paints – new enamels are less likely to suffer from this. The best option is to sand and repaint with a new good quality paint

surface preparation is crucial for success – the sanded surface must be dry and free of all contaminants before painting begins

some paint manufacturers recommend using a primer undercoat first. If there are any water stains on existing surfaces, stain blocking primer or primer undercoat should be used

use paint appropriate for the circumstances – for example, enamel on contact surfaces such as windows, doors and cupboards

in general, it is acceptable to use water-based paint to paint over a surface previously painted with solvent-borne paint, so long as the surface has been prepared appropriately. A primer undercoat may be useful

to work out whether an existing paint finish is water-based or solvent-based, soak a cotton ball in rubbing alcohol (isopropyl or ethyl alcohol), an acetone-based nail polish remover or lacquer thinner. Rub it over a small, inconspicuous section of paint. If paint comes off, it is water-based; if unaffected, it is a solvent-based paint

if you suspect some of the paint layers may be several decades old, be aware of the possibility that the old paint may contain lead. Lead can be a health hazard if fumes, dust or paint fragments are swallowed or breathed in. For more information see Health and safety: lead-based paint