Because techniques and procedures vary from surface to surface, we'll look at them separately. If your surface type does not appear here, either use the procedure for the one that's nearest to it, or ask your local stockist for more information. Remember, the aim of all preparation is to create a sound surface.
Bare Surfaces - Bare Timber
Timber which has been exposed for more than four weeks should be sanded back to a fresh, new surface before painting. A grey or weathered surface is an unsound base on which to paint and will encourage peeling and flaking. Punch any nails well below the surface, spot prime (just paint a little dot of primer into the nail hole) and fill the nail holes with a fillers. Sand smooth and apply Acrylic Primer/Undercoat to maximise paint durability.
Nail Head Staining
Uncoated steel nails, or old nails on which the galvanising has broken down, can cause staining as heat from the sun draws moisture towards the exterior surface. If any nails have risen to the surface and can be easily removed, replace them with new rust-protected nails. Sand or wire brush the stains off the paint and exposed old nailheads until the surface is bright and shiny. Replace old steel nails with galvanised nails wherever possible.
Counter-sink nails to 3mm-4mm below
the surface and spot prime (just paint a
little dot of Metal/Steel Primer into the nail
hole) and fill the nail holes with an exterior
filler. Sand smooth and prepare the rest
of the surface for painting.
Some common building timbers such as cedar and oregon contain natural staining materials called tannins. These can be dissolved and carried to the surface by moisture passing through the wood.
If you are using lighter paint colours which will show the tannin staining, prime the surface with an Oil Based Primer.
Bare Masonry, Bricks and Cement Sheeting
Remove all loose material with a stiff bush (A brass wire brush is ideal). Any mortar spatters that will not chip off can be removed with muriatic acid - handle this with care; skin and eye protection are essential. If the surface is powdery, porous or brickwork is highly glazed, priming is recommended to improve adhesion and durability. Use an Acrylic Primer/Undercoat, or a Sealer Binder on powdery areas.
New concrete and cement render surfaces must be allowed to cure for a minimum of 28 days to neutralise alkali.
Make sure the surface is clean and free of rust. Rust may be removed by sanding or wire brushing then treating with rust remover. Clean by wiping down with a cloth dampened with turps to remove any traces of oily residues or grease that remain from the manufacturing process.
Apply metal primer onto ferrous surfaces and galvanised iron primer onto non ferrous surfaces. To avoid peeling, never apply oil based enamel paints direct to bare galvanised iron. Always prime with Galvanised Iron Primer first.
New Plastic Downpipes and Spouting
Wipe down with a cloth dampened with turps before lightly sanding the surface to provide a sound key for the paint to adhere to. Wipe down again with a water dampened rag before painting.