House Painting - Resolving Common Paint Problems
Whether you're dealing with interior or exterior painting, there are some common paint problems such as flaking, peeling or blistering paint that must be corrected first before attempting to paint again.
Flaking and Peeling
Possible Causes:
- Probably the top of the list of common paint problems. Paint simply doesn't stick. The surface might have been dirty.
- It might have had too many layers of paint already.
- The wrong type of paint might have been used.
Remedy:
- Locate and eliminate sources of moisture. Is area near a bathroom or kitchen? Is there seepage or leakage from eaves, roofs or plumbing?
- Scrape off old paint where the flaking is occurring up to 12 inches away from the flaking condition.
- Sand surface to fresh wood and spot prime with recommended interior or exterior undercoater.
- Seal all seams, holes, cracks against moisture entry with caulking compound.
- Apply top coat of house paint according to label directions.
Alligatoring, or Checking
Possible Causes:
- Paint has many reptilian-looking interconnected cracks. The outer coat has not adhered properly to the paint beneath.
- Previous paint film applied in several heavy coats without sufficient drying time between coats or use of undercoater not formulated for finish coat.
Remedy:
- Sand surface smooth - often right down to the raw wood.
- Apply one coat of exterior undercoater and one top coat of recommended house paint according to label directions.
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Blistering
Possible Causes:
- Bubble form under paint.
- Moisture trapped in siding is drawn from wood by sun's heat and pushes paint from surface.
- The temperature was too high when the top coat was applied.
Remedy:
- Locate and eliminate sources of moisture. Is area near a bathroom or kitchen? Is there seepage or leakage from eaves, roofs or plumbing?
- Scrape off old paint where the blistering is occurring up to 12 inches away from the blister condition.
- Sand surface to fresh wood and spot prime with recommended exterior undercoater.
- Seal all seams, holes, cracks against moisture entry with caulking compound.
- Apply top coat of house paint according to label directions.
Chalking
Possible Causes:
- Most exterior paints are formulated so that the surface gradually breaks down into a powdery chalk that takes dirt and grime with it when rain washes it away. This feature keeps the paint looking clean. Chalking surfaces, however, will not hold new paint.
Remedy:
- Scrub a chalking surface with detergent and rinse well.
- Apply top coat of house paint according to label directions.
Cracking and Scaling
Possible Causes:
- Fissures open in the paint, allowing in moisture, which lifts off the paint. Usually caused by aging paint that has lost its elasticity and can't change with temperature and humidity changes.
- It may also result from moisture seepage or air pollution.
Remedy:
- Locate and eliminate sources of moisture before painting.
- Sand surface smooth - often right down to the raw wood.
- Apply one coat of exterior undercoater and one top coat of recommended house paint according to label directions.
- Wash newly painted areas periodically.
Wrinkling, Running and Sagging
Possible Causes:
- The paint puckers, drips, or lumps. Often the result of applying too thick a coat or of poor painting technique.
- It can also be caused by painting over an undercoat that is not yet dry.
Remedy:
- Strip the surface and repaint.
- Be sure to allow the first coat to dry completely before applying an additional coat.
Top Coat Peeling
Possible Causes:
- Usually found on overhanging horizontal surfaces and other areas protected from weather. It is caused by poor adhesion of previous coat of paint from build up of "salt" deposits which are not washed away by rain.
Remedy:
- Sand surface thoroughly to remove all peeling paint.
- Wash sanded surface with solution of three heaping tablespoons (1/3 cup) tri-sodium phosphate to one gallon of water.
- Rinse well and allow to dry.
- Apply one coat of undercoater and one top coat of house paint according to label directions.
Mildew
Possible Causes:
- Mildew is a fungus that thrives on high humidity and high temperature. If left on the surface and painted over, it will grow through the new coat of paint.
- Usually found in shady, protected areas that don't get enough sun or air to prevent growth of the fungus.
Remedy:
- Scrub the entire surface with a solution of (1/3 cup) trisodium phosphate (TSP), eight tablespoons (1/2 cup) household bleach, in four quarts of warm water.
- Apply one coat of mildew-resisting primer. Note: Mildew-resistant additive may be added to an undercoat if mildew conditions are severe and an oil based top coat is used. The additive in a finish coat should be avoided.
- Apply one top coat of mildew and fume-resistant white or latex house paint.
Flaking/Chalking Masonry
Possible Causes:
- Inadequate surface preparation. Paint flakes off in "scales" or powders and chalks off.
Remedy:
- Remove flaking and chalking paint by wire brushing or sandblasting.
- Seal all surface cracks from moisture with a suitable masonry patching compound.
- Apply masonry primer according to label directions.
- Apply two top coats of latex house paint or exterior masonry paint according to label directions.
Redwood and Cedar Staining
Possible Causes:
- Moisture in siding dissolves coloring matter in wood. Colored water escapes through breaks in paint films and drips from underneath overlapping boards. Stain is deposited as water dries.
Remedy:
- Locate and eliminate sources of moisture before painting. Wash stained surface with mixture of 50% denature alcohol and 50% clean water.
- Allow surface to dry 48 hours.
- Then apply two coats of house paint according to label directions.
Peeling Gutters
Possible Causes:
- Peeling or cracking of galvanized metal gutters, downspouts, etc. Improper metal primer or no primer used on galvanized metal results in paint film with little or no adhesion.
Remedy:
- Strip off all loose paint by scraper, wire brush, or best of all, power wire brushing. It is very important that all loose paint be removed or succeeding coats of paint will subsequently peel away, too.
- When finishing with oil base top coat, prime bare spots with galvanized metal primer.
- When finishing with latex top coat, apply latex paint directly to bare galvanized areas after cleaning with a solvent such as mineral spirits. Allow solvent to evaporate.
- Finish with a top coat of latex or oil base house paint. Use two top coats when a color change is involved or substantial bare metal is exposed.
Nailhead Staining
Possible Causes:
- Excessive moisture contributes to rusting of uncoated steel nails used in construction.
Remedy:
- Locate and eliminate sources of moisture.
- Sand or wire brush stained paint and remove rust down to bright metal of nailhead.
- Countersink nailhead 1/8-inch below surface of siding.
- Immediately spot prime countersunk nailhead with recommended exterior undercoater.
- Fill primed, countersunk holes with caulking compound. Apply two top coats of house paint according to label directions.
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