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.

Exterior Paint
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.

Step 1

Preparing Masonry for Painting

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.

Step 2

Cleaning Old Walls

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.

Step 3

Painting Metal Exterior Pipework

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).

Step 4

Painting and Treating Exterior Woodwork

Paint or a natural wood preservative finish are essential for exterior woodwork because it is prone to damage from the elements. Maximize protection by using hardwearing fillers and exterior-grade paints. Problems can still occur. The heat of the sun can cause sap to bubble out of knots, blistering the paintwork. Use a heat gun followed by knotter to prevent further damage. This technique can also be used on bare wood, prior to painting. Small cracks in paintwork can lead to minor rot problems. Pellets of wood preservative or wood filler repair are an excellent way to repair rot damage. Large areas of rotten wood need to be replaced.

Wooden siding is treated like any other exterior woodwork, but it must be washed down thoroughly in order to remove all signs of dirt. In some circumstances, fungicide may be required, which can be applied as shown for masonry walls.

Step 5

Dealing With Knots

Scrape all the sap and excess paint away from the affected area (Image 1).

Use a heat gun to heat up the sap so that it bubbles out from the knot. Keep using the heat gun until the sap stops flowing (Image 2).

Sand the area to remove residue and provide a clean, smooth surface for painting (Image 3).

Apply sealer to the knot using a small brush. Once this is dry, you can prime and paint the area using exterior-grade paints (Image 4).

Step 6

Using Preservative Pellets

Scrape the rot back to sound wood (Image 1). Allow the area to dry out, then apply wood hardener to the exposed wood.

Use a two-part wood filler specifically for exterior use to repair the damage caused by the rot (Image 2).

Drill holes around the rotten area. (Drill bit size will be specified on pellet packaging.) Push pellets into the holes, making sure they sit below the wood surface (Image 3). You can then fill the holes with more exterior filler. Sand the treated area smooth before priming and painting. Like many preservative products, pellets contain toxins, so be sure to wear gloves when handling them.

Step 7

Treating Windows and Doors

Wooden windows and external doors rely on paint or a natural wood finish for protection. Start work early in the day so you can close the windows and doors before night. Apply paint using the technique specified for wood.

Cracked puttywork can let down the finish of an otherwise well-painted window or glazed door. As long as the putty is sound, fill it with an all-purpose filler, then sand and paint with the wood. Take care not to allow the sandpaper to touch the glass surface, because it will scratch it. Where putty is very loose or missing, remove as much as possible, dust away any debris and re-putty.

Step 8

Treating External Door Edges

Take the door off its hinges. Apply preservative primer to the top and bottom edges of the door (Image 1).

Prime and paint the edges when the preservative primer has dried using exterior paints (Image 2).

Step 9

Vinyl and Metal Windows

Vinyl doesn't require painting. It can be kept bright and clean with a non-abrasive cleaner. Some cleaners denature and degrade rubber seals or gaskets, so check the manufacturer’s guidelines. When painting surrounding wall surfaces, take care to mask up vinyl as removing any paint overspray can be very difficult.

Metal windows or parts of windows are often factory-coated and so don't require painting. Old metal windows can be painted using much the same system as normal wooden windows, except that an appropriate primer must be used to prevent rust damage.