Exterior Paint Solution Center

• Application of a hard drying topcoat over a non-dry coating.
• The topcoat drying too quickly from being in the sun.
• Natural aging of oil-based paints. As temperatures fluctuate, the constant expansion and contraction forces result in the loss of paint film elasticity and eventual cracking.

• Sand the surface and use a quality exterior primer over the old, hard previous coats. Oil paint should be completely removed by scraping and sanding the surface; a heat gun can be used to speed work on large surfaces, but take care to avoid igniting paint or substrate. The surface should be primed with a high quality latex or oil-based primer, then painted with a top quality exterior latex paint.

• Painting a warm surface in direct sunlight.
• Application of oil-based or alkyd paint over a damp or wet surface.
• Moisture escaping through the exterior walls (less likely with latex paint than with oil-based or alkyd paint).
• Exposure of latex paint film to a dew, high humidity, or rain shortly after paint has dried, especially if there was inadequate surface preparation.
   

• If blisters go down to the substrate, locate and remove the source of moisture, i.e. ventilation, repair and replace loose caulking. Remove blisters (see below).
• If blisters do not go all the way down to the substrate, remove them by scraping, then sanding; prime any bare wood and repaint with a quality latex exterior paint.

Chalking

• Use of a low-grade, highly pigmented paint.
• Use of an interior paint for outdoor application.
• Use of an alkyd based paint*
  
  *ln general, alkyd based coatings will chalk more than their latex counterparts. Use a latex coating if the structure is subjected to severe sun exposure.

• First, remove as much of the caulk residue as possible, using a stiff bristle brush (or wire brush on masonry) and rinsing thoroughly with a garden hose or power washing equipment. Check for any remaining chalk by running a hand over the surface after it dries. If noticeable chalk is still present, apply a quality oil-based or an alkyd modified latex primer (or comparable sealer for masonry), then repaint with a quality exterior coating; if little or no chalk remains and the previous paint film is sound, no priming is necessary.

Chalk Run-Down

• Use of a low quality, highly pigmented paint.
• Use of an interior paint for an outdoor application.
• Erosion of factory-finished metal siding.

• Remove as much of the chalk residue as possible (see Chalking). Scrub any stained areas with a stiff brush, using a detergent solution; rinse thoroughly. In cases of severe staining, an acid wash may be necessary. Either way, if the affected area dries to a different color, consider painting it with a quality latex paint. Eroding aluminum siding should be thoroughly cleaned (power washing recommended) before painting with a quality latex exterior paint.

Cracking / Flaking

• Use of a low quality paint that has inadequate adhesion and flexibility.
• Over thinning the paint or spreading it too thin.
• Poor surface preparation, i.e. when the paint is applied to bare wood without priming.
• Painting under cool or windy conditions that make latex paint dry too fast.

• It may be possible to correct cracking that does not go down to the substrate by removing the loose or flaking paint with a scraper or wire brush, sanding to feather the edges, repainting.
  If the cracking goes down to the substrate, remove all of the affected area by scraping and sanding, then prime and repaint with a quality latex exterior paint.

Dirt Pickup

• Use of a low quality paint, especially lower grades of flat or satin finishes.
• Structural conditions: No gutters causing soil to splash onto the siding.
• Environmental conditions: air pollution, car exhaust and flying dust collecting on house body and horizontal trim.

• Wash off all surface dirt. If unsure whether the problem is dirt or mildew, conduct a simple spot-test (see Mildew). Clean off dirt with a scrub brush and detergent solution, followed by a thorough rinsing with a garden hose. Heavier dirt accumulations may require the use of a power washer.
• While dirt pickup can’t be eliminated entirely, top quality exterior latex paints typically offer superior dirt pickup resistance and washability. Also, higher gloss paints are more resistant to dirt pickup than flat paints, which are more porous and can easily entrap dirt.