Painting Exterior Surfaces
There are many types of exterior surfaces that might need to be painted, brick, cement blocks, clapboard, cedar, and paneled wood products. The primary rule to exterior painting is to make sure that dirt, flaking paint, and other obstructions are removed. This can be done with a scraper and a brush, but it can be done much more efficiently with a power sprayer. Spray on a cleaning fluid and then spray it off with pressurized water. Start at the top and work your way down, holding the nozzle about six inches and at a 45 degree angle from the surface.
If you find mildew during this process, spray it with a solution of 1 cup bleach for every gallon of water. This should kill the spores. Mildew actually feeds on the oil in oil-based paints. So if this is a problem around your home and you want to use an oil-based paint, you should add an inhibitor to the paint. Wood, concrete, and other surfaces should dry thoroughly before filling holes and depressions with wood putty or caulk. Rust streaked areas should be sanded if the stain is not too deep. The nail can be pounded in about 1/8 inch below the surface of the board and covered with a finger swipe of caulk.
Metal surfaces such as railings and gutters should also be prepared. Remove loose paint with a brush or power brush. If bricks are cracking or mortar has come loose, repair the damage before painting. There is alkali in masonry and it will leach out under a painted coating. For this reason it should be prepared with a solution of muriatic acid (1 part acid to 5 parts water). This acid is very caustic, so be careful. When using it, wear rubber gloves and goggles. Pour the water first, then add the acid to prevent splashing. Scrubbing this compound into concrete is called etching. Once the etching has been completed, wash it off with water.
Of course new surfaces will not need to be pressure washed or scraped and brushed. Nevertheless, a primer coat should always be applied to bare surfaces whether the surface is new or has just been exposed from beneath peeling paint. The primer will help the regular coat of paint to adhere. Also some surfaces require a special primer, especially, metal, brick and masonry.
Masking can help you create straight lines, but is not as essential as it is for interior painting. Rough lines, from a distance are not likely to be noticeable by the casual observer. Like interior surfaces that are to be exempt from paint, be sure to cover these surfaces with drop cloths to avoid splatters, which are even more likely to occur on an exterior than an interior paint job. If you do not mask windows be prepared to scrape off excess paint after the paint job is complete.
When painting exterior surfaces the do-it-yourselfer has one major consideration that is not usually a factor for interior surfaces, the weather. Paints have optimum conditions in which they should be applied. It is best not to paint in extreme heat or cold and in the presence of precipitation. Check your paint can label for temperature restrictions.
Generally paint the siding first and then proceed to the trim, guttering, and windows. Work from the top down, but as much side to side as possible while mounted on ladders to avoid a lot of up and down motion. Rollers are not used as often for exterior surfaces because siding usually comes in small widths that are easier to handle with a brush, but this is not always the case. T-111 siding can largely be covered with a roller and the recessed areas painted with a brush. For clapboards, coat the underside of several boards first and then paint the face of the boards. Cedar shingles with their uneven surface can be painted with a 4" brush or a pad applicator. You may also use a sprayer to coat most surfaces.
Be very careful when working overhead on soffits. Eaves that are made of wood need special treatment. Sand the old paint to rough it up, be sure to use proper primers and paints that will adhere to metal. Paints with zinc or aluminum additives are best for this purpose.
When painting with a brush be sure not to over-burden the brush with paint as it will drip and can become very messy when working overhead. Remember the business end of a brush is at the ends of the bristles, not the sides of the bristles.
Painting exterior surfaces can be a long process that must be done over several days. Get help if you can. Most of the paint job will not be precision work and people can be trusted with much of the grunt work. Painting with a brush can be tiring on the arms. There is no absolute proper way to hold a brush; so use different handholds at different times to relieve some of those stressed muscles. Take frequent breaks and drink lots of water.