- Home Improvement
House Painting Prepairation
Unfortunately, much of the work in painting is not in the painting itself, which at least shows the pleasing results of your labor, but in the preparation. Preparing the siding for painting, often makes the house look worse-temporarily- but is the single most important chore to make the new coat of paint last longer.
Dirty and continued wet surfaces must be remedied before a new coat of paint can do its job. In addition, painting over loose paint is just an invitation for the loose base paint to fall away, negating your efforts.
Peeling or cracking paint generally is caused by moisture getting into the board behind the paint and pushing it off from the inside. The moisture can come from rain, and when gutters are not channeling water away from siding, when cracked caulking or eaves-trough allow water behind boards, or when water stands against the house at ground level. Or the moisture can come from inside the house, as when steam or splashing from a shower wafts or seeps through the wall to the inside of the siding. These problems must be corrected at the source before paint is applied to the siding, or new moisture will push off the new paint, and you would have wasted your time and money.
If the source of water is from a faulty gutter, eave-trough, or caulking, fix it first. If the source is a leaking bathroom wall that allows moisture to pass through the siding, repair the interior wall of the bathroom.
On the outside, there are additional methods to let the moisture escape. For lapped siding, you can drive thin wedges between the boards. For tongue and groove siding, you can drill small holes into the siding for ventilation. Both techniques allow for moisture to escape easily so that it will not push against the paint from the inside. The problem of moisture popped paint is especially prevalent in older homes, where layer after layer of paint have formed an impervious barrier to moisture flow; cracking and peeling result.
If these remedies have been tried and ruled out, and you still have moist wood, ask a home inspector for an opinion. Sometimes, peeling is the result of a poor painting job. Rarely, it may be caused by the wood itself- some resinous pine simply will not hold paint, and it might be best to cover these woods with a new siding.
After correcting the leakage problems, the next step is to remove peeling or cracked paint.
CAUTION: Wear protective goggles and a dust mask.
If you suspect that the old paint contains lead, and 80 percent of pre-1950 homes do, call your local health department. They will tell you how to test for lead paint. Ask them about local laws on lead paint removal and if they can recommend local contractors certified in lead paint removal.
If there are no laws about lead-paint removal,take these precautions as a minimum: (1) seal off the area with a windscreen from the building to the ground and use a drop cloth on the ground itself; and (2) use removal methods that make as large a particle as possible large particles are more easy to clean up and are not so easy to become airborne dust, which is poisonous.
Wet scraping is one method used by contractors, and water blasting is an option if the runoff can be contained and carried away. For your health and that of those around you, burning and sanding are the worst methods-the fine particles created becomes absorbed into the blood stream and can cause irreversible brain damage, to which young children are particularly susceptible. If your house was built after 1975, it is unlikely to have lead-based paint on the exterior.
A fast way to remove loose paint is to use a 3000 lbs/ SQ inch pressure washer. It not only blasts away loose paint but also washes the house, doing the job in about half the time for a fifth of your effort, although some hand scraping may still be needed. Incidentally, sometimes a dingy appearance may signify only that your house is in need of a wash, not a new coat of paint; the neighbors will be just as impressed with your home's new look and considerable less trouble and cost to you.
If your house has a condition called chalking, which is the presence of dusty pigment that has separated out from the surface, you eliminate that at the same time as you wash away regular dirt. If you have mildew, you can get rid of that too, by mixing bleach solution in with water-washers usually comes with tanks into which such mixing solution can be placed.
After removing loose paint and allowing the siding time to dry, prime the bare wood as soon as possible.
Use an acrylic latex primer that is compatible with the finish coat you will use, preferably that is made by the same manufacturer. Preparation for painting can be a time-consuming nuisance. But done well, it makes the paint last twice as long as when done poorly.