Contact us
Tony Isgrove's
Painting & Decorating Specialists
2/89 Whiting Street, Artarmon 2064
Sydney, NSW, Australia
Tel: 02 9437 1997
Fax: 02 9437 1447
tony@paintanddecorate.com.au
|
|
Exterior painting » Preparation guide
Your finished job will only be as good as the preparation. Paint applied over a poorly prepared surface will not last as long or look as good. To avoid lengthy preparation, freshen up your paintwork before it deteriorates!
Choosing the right primers, undercoats and topcoats is an essential step in achieving excellent results.
Timber
Before you start surface filling, any rotten or decaying timber must be removed and replaced. The surface should be prepared as outlined below. Sort out the cracks and holes into those which will be subject to movement (usually the joint between two surfaces or materials) and those which will be stable.
There are a number of fillers you can use. These range from linseed oil putty or cellulose based compounds. Linseed oil putty is popular, but it becomes dry and brittle with age. Timber should be primed prior to being filled if linseed oil putty is used. Cellulose fillers are more flexible.
To fill holes or dents, simply make sure the area is clean and apply the filler with a spatula or putty knife. If the hole is particularly deep you may need to overfill or apply a second lot of filler as it will shrink during setting.
Where you think movement is likely to occur, in places like the joints between walls and windows, an exterior flexible filler is recommended. A variety of these are available and they are usually applied direct into the crack with a caulking gun. |
Masonry and Brick
Filling small holes in brick or render is simple. Scrape away any loose paint and fill the hole with an exterior filler using a broad-bladed knife or scraper. Deeper holes may need overfilling or a second application to compensate for shrinkage during setting. Use a brush or rag to roughen the filler before it is completely dry to match the texture of the surrounding surface.
Larger holes may need to be repaired with a 6:1 mix of sand and cement. Mix it dry and then gradually add water until it is of a doughy consistency. Wet the area you're going to patch and fill with the mortar using a trowel or wide scraper. Using a pre-mixed filler will usually shorten the drying time.
If your smoothing with a knife is less than perfect, a quick wipe with a damp sponge will take out small ridges and save sanding later on. |
Sanding
Surfaces must be sanded smooth before any paint is applied. Sanding can be a laborious job so if you have a significant amount to do it may be wise to consider some of the mechanical help available.
On paintwork and wood, a general purpose sandpaper can be used. On bare metal you'll find cloth-backed emery paper will last much longer and do the job faster. |
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 dob of primer into the the nail hole) and fill with a filler. Sand smooth and apply Dulux Prepcoat Acrylic Primer/Undercoat to maximise paint durability. |
Nail Head Staining
Undercoat 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 old steel nails have risen to the surface and can be easily removed, replace them with new galvanised nails. Sand or wire brush the stains off the paint and exposed old nailheads until the surface is bright and shiny. Counter-sink nails to 3mm-4mm below the surface and spot prime (just paint a little dob of metal primer into the nail hole) and fill the nail holes with filler. Sand smooth and prepare the rest of the surface for painting. |
|
|
PH 02 9437 1997
