Filling and Patching
Timber - rotten or decaying timber should be removed and replaced. Holes should be filled with a good quality filler such as Polyfilla Painters Putty. Apply filler with a putty knife, overfill to compensate for shrinkage during setting. Where movement is likely to occur, use an exterior flexible filler such as Polyfilla High Stress Gap Sealant.

Masonry and Brick
Scrape away any loose paint and fill holes using an exterior masonry filler using a broad-bladed knife or scraper. Use a brush or a rag to roughen the filler before it is completely dry to match the texture of the surrounding surface. Larger holes may require a ready mixed filler such as Polyfilla Ready to use Large Cracks.

Sanding
If you have a lot of sanding to do consider using a mechanical sander. On paint work and wood, a general purpose sandpaper can be used . On bare metal a cloth backed emery paper will last longer and do the job faster.

Bare Timber
Timber which has been exposed to the elements for more than four weeks should be sanded back to a fresh, new surface. A grey or weathered surface makes an unsound base and will encourage peeling and flaking. Punch any nails well below the surface, spot prime and fill the nail holes with an exterior timber filler. Sand smooth and apply Dulux Prepcoat Acrylic Primer Undercoat to maximise paint durability.

Nail Head Staining
Replace old steel nails with galvanised nails where ever possible. Hammer nails to ~3mm below the surface and spot prime (just paint a little Dulux Prepcoat All Metal/Steel primer into the nail hole) and fill the holes with an exterior timber filler. Sand smooth and prepare the rest of the surface for painting.

Tannin Stains
Some common building timbers contain natural staining material called tannin. These can be dissolved and carried to the surface by moisture on the wood. If you are using bare timber of this sort with lighter paint colours which will show the tannin staining, prime the surface with Dulux Prepcoat Oil Based Primer.

Bare Masonry, Bricks and Cement Sheeting
Remove all loose material with a stiff brush. If surface remains powdery or porous, priming is recommended to improve adhesion and durability. Use Dulux Prepcoat Acrylic Primer Undercoat, or Dulux Prepcoat Sealer Binder on powdery areas.

Cement render, concrete bricks and mortar must be allowed to cure for a minimum of four weeks, and concrete for a minimum of 8 weeks, before painting with an acrylic paint. Much longer curing times are required if you plan to use oil based paint.

Bare Metal
Ferrous Metals (those that rust) - make sure the surface is clean and free of rust. Remove rust by sanding or wire brush then treating with a rust remover. Apply Dulux Prepcoat All Metal/Steel primer.
Non -ferrous metal (those that do not rust) - Never apply oil based enamel paints direct to galvanised iron. Prime with Dulux Prepcoat Galvanised Iron Primer first, or use a water based acrylic paint.

New Plastic Down pipes and Spouting
Wipe down with a cloth dampened with turps before lightly sanding to provide a sound key for the paint to adhere to. Wipe again with a water dampened rag before painting.

Previously Painted Surfaces
Test the paint in several areas by cutting with a sharp knife and pressing 10 cm or so of adhesive tape firmly across the middle of the cut. Rip the tape away quickly - if any pieces of paint come with it, you will need to strip the loose paint.

Stripping
If the paint needs to be stripped back, the most common method is to use a heat gun or a chemical stripper such as Polystripper. For small areas, a manual or drill mounted wire brush or dry scraper may be adequate.

Sound Paint Work
If the paint work is in good condition, a light but thorough sand should be sufficient. Any small areas of peeling or cracking may be sanded back. Holes or defects should be filled and spot primed. Painted brick or masonry should be washed with a high pressure cleaner and a stiff bristled brush.

Blistering Flaking and Peeling
On wooden surfaces this is usually caused by moisture trapped beneath the paint. It happens most frequently on the north and west sides, as these areas receive the most heat from sunlight and is more common with dark colours have been applied over old paint. The first thing to do is remove the source of the moisture. Around windows and doors, look for cracks and seal them. In the walls the problem may be condensation, so the installation of additional vents may be required. Strip as much as practicable, sand smooth and prepare using Dulux Prepcoat Exterior/Interior Acrylic Primer.

Go to more information on surface preparation in the FAQ section.

Chalking on timber
Over time Oil based enamel breaks down in our high UV sunlight to create a chalky or powdery surface. This should be scrubbed off and the adhesion of the old paint tested before repainting.

Mould
Remove surface mould growth by using a household bleach (hypochlorite) solution prepared by mixing one part bleach with 3 parts of water. Wear gloves and goggles to protect yourself from splashes, and apply with a thick scouring pad, rubbing to remove the mould. Leave the solution on the surface for 15 minutes then wash down with clean water. This process may need to be repeated to fully remove mould growth.

Go to more questions on mould in the FAQ section.