Surface Preparation

Safety review: Avoid high work when you’re tired. Place a ladder bottom out from a building no more than one-fourth the ladder’s height. Set firm footing for all ladders and scaffolding. Keep your hips between the sides of the ladder; don’t lean out beyond the sides. Wear clothing for freedom of movement. Hang your paint can with a S-hook or a bent coat hanger, so you will have both hands free. Wear hard-soled shoes to fight foot-on-rung fatigue. Moreover, you’re well-advised to wear a respirator mask during all phases of prep and painting.

Also, any surface prop is prodigiously messy, so rent heavy duty tarps to cover your lawn and shrubs. Shake tarps daily to keep up with the debris. An untarped job can mean picking paint scraps out of your grass for years or-- even worse-- possibly exposing neighborhood kids to old lead-based paint.

Persistent moisture problems: Deal with problems of persistent moisture before painting. Moisture from the atmosphere is rarely a problem unless it gets behind the membranes- the roof and siding- designed to keep it out. Here are some important considerations:

1. A healthy roof should be your first priority. Repair damaged roofing shingles and flashing around chimneys, stack pipes, and similar elements. Maintain gutters and downspouts to prevent water backup.
2. Windows and doors should have cap flashing, and their perimeters should be caulked.
3. Caulk and renail all loose siding, filling holes with wood filler, and priming all such spots.
4. If a given face- especially the southern face of a house- has deteriorated, strip off and replace it rather then repair it piecemeal.
5. Do not use green wood for repair; it shrinks too much.

Scraping and spot-priming: Before scraping and spot-priming, spread tarps on the ground and over all plants. Scrape back loose paint at least a foot beyond deteriorated area, using a wire brush, a wide-blade knife, or a scraper. Be sure to scrape the lower edges of clapboards and beneath windowsills. Once loose paint has been removed, sand al surfaces to ensure a good bond to the following coat. Lightweight block sanders are the most useful type; heavy-duty commercial belt or rotary sanders sand too deeply and often leave swirl marks. Brush off sawdust and dirt with a house broom or the air hose of a compressor.

Spot-prime all areas scraped down to the wood, as well as filling in nail holes, caulking or filling cracks, and filling in knotholes.

Spot-prime all areas that need extra attention; wood exposed by scraping, filled nail holes, caulked cracks, siding discolored for any reason. If there are bleeding knots or rusty nail heads, prime them with primer-sealers such as BIN. Shellac also works on knotholes. For metal gutters, trim and such, use a metal primer. Fill sunken nail heads and small depressions with exterior spackle. Where wood is badly deteriorated; you should remove it, but if the rot is localized and the trim would be difficult to replace, scrape loose matter away and impregnate the remaining area with an epoxy filler.

Finally, if the house if generally grimy, scrub it with a broom or scrub brush dipped in a pail of detergent solution (one cup detergent per gallon of warm water). Rinse with a garden hose. Let the scrubbed surface dry completely before painting it.

To thoroughly wash and rinse an exterior however; rent a pressure washer, which has a small boiler and a high-pressure electric pump. (Have the supplier explain its use in detail.) Using a detergent especially designed for such a unit, you can dislodge blistered paint, thus eliminating a lot of scraping. The tool also helps you to identify problem areas, say, incipient rot along eaves, for you’ll see poorly adhered paint falling off in chunks. With the same tool, rinse the surface with hot, clean water. Because the pressure forces water into cracks, allow 2 to 3 days of dry weather for the exterior to dry before painting.

Mildew control: First, determine whether a discolored spot is actually mildew. Wipe it with a rag dipped in bleach; if it’s mildew, the spot will disappear, if merely dirt, the spot will remain.

Get rid of the mildew by making the surface inhospitable and inedible to organisms that thrive on it. To 1 gallon of warm water add ½ cup household detergent, ½ cup trisodium phosphate or 1 qt liquid bleach (the variety containing sodium hypochloride). Do not mix chlorine bleach and ammoniated cleaners, however, for that may produce a toxic gas. Wearing gloves and goggles, scrub the mildewed area with this solution. Rinse the spot with a garden hose and allow it to dry. Prime the area with a mildew-resistant primer- one coat if it’s alkyd or oil based, two coats of latex.

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