More in Painting
Most of the tools and techniques for painting exterior surfaces are the same as those used for interiors. However, materials are often chosen for their greater durability. Painted masonry can last up to 10 years, and wooden windows up to five years before recoating is necessary. Surfaces need to be filled and sanded before you paint. Additional preparation is often required. Vegetative growth and rot are more common problems on exterior surfaces, and how to treat them is shown here. If you are working on the outside of your house, remember that ladders and scaffolding will almost certainly be needed for access.
Items painted with light colors reflect the sun's heat. This reduces paint problems due to expansion so they need repainting less often. Exterior latex, also known as masonry paint, is used outside. Apply it in the same way as interior latex. Coverage is often less: 100–1,000 square feet per gallon. Coat woodwork and pipework with gloss. You can use special paint for rusty metal.
Remove any vegetative growth from masonry walls, and clean them down thoroughly. Small holes in masonry can be filled using all-purpose powder fillers as long as they specify exterior use. New masonry finishes should not need any further treatment.
Old masonry may need some more extensive repair. It will also benefit from an application of fungicide, and stabilizing solution if the surface is flaky. Once the surface is clean and dry, fill any remaining holes and sand as normal.
When you come to paint walls, the best choice is exterior latex, often called masonry paint. Apply a mist coat — the paint you are using diluted with 10 percent water — followed by two full-strength coats. Paint from the top down, covering the walls before woodwork and metalwork. Some deviation from this basic plan is often necessary because of access. You may find it easiest to paint roof details such as soffits, fascias, and bargeboards, followed by the top section of wall, before tackling the lower surfaces.
Use a stiff brush to remove any loose paint, masonry, vegetative matter or dirt from the wall (Image 1).
Apply fungicidal solution using the manufacturer's guidelines (Image 2). Leave for 24 hours, then use a pressure washer to clean the surfaces. (Wear any protective clothing specified.)
Check the wall surface. If it is powdery to the touch, you need to use a stabilizing solution (Image 3).
Apply the stabilizing solution with a large paintbrush (Image 4). When it is dry, the wall is ready to fill, sand and paint.
Exterior pipework is usually made of metal or plastic. Exterior metalwork is treated in the same way as that inside the home, except that special exterior metal paints generally offer greater durability. Plastic items are simply cleaned when any dirt or vegetative growth accumulates. If you do wish to coat plastic pipes, apply two coats of gloss over a primer coat.
Brush down the metal. Remove any flakes of paint and rust right down to bare, shiny metal (Image 1). Some metal paints can be applied directly over rust.
Prime patches of exposed metal using a metal primer specified for exterior use (Image 2).
Apply exterior-grade gloss paint, laying off the paint carefully as you work. Shield the wall with a piece of cardboard (Image 3).
Excerpted from Do It Yourself Home Improvement
© Dorling Kindersley Limited 2009