Crocodile crack: Similar rules crocodile flake crack phenomenon on the film surface.
      Possible causes:
One reason: the flexibility of a strong coating (such as latex primer) coating on a high hardness of the coating (such as alkyd enamel).
Two reasons: When the primer is dry topcoat.
Three reasons: oil-based paint due to fluctuations in temperature and natural aging.
Four reasons: When the primer is dry topcoat.
Five reasons: oil-based paint due to fluctuations in temperature and natural aging; continuous stretch film led to loss of elasticity.
      Workaround: eradicate the old paint and polished surfaces. Large-scale construction can be used to improve the thermal spray gun construction, thermal spray gun can be used to improve the efficiency of construction, taking care to avoid igniting paint or substrate. Surface use high quality latex or oil-based primer primer, then paint quality exterior latex paint.

      Foaming: As the partial loss of paint adhesion, the substrate surface separation bubble phenomenon.
      Possible causes:
First, the painting in direct sunlight hot surfaces.
Second, on the wet surface coating solvent-based or alkyd paint.
Third, the moisture through the outer wall of volatile (relative to solvent-based or alkyd paint, the paint is not easy to happen). Shortly after the paint dried, especially when inadequate surface preparation, is exposed in the dew, moisture or rain.
      Solution:
Method One: If the bubble continued to the substrate: try to eliminate the source of moisture. Repair loose caulk; consider installing exhaust fans.
Removal of air bubbles (see next entry).
Method Two: If the bubble is not extended to the base: they scrape off, followed by grinding; occur anywhere bare wood should be primed and re-painted high-quality exterior paint.
Method three: powder: the weathering process, the surface of the film will be a thin layer of powder is formed, it can cause paint to fade. Although some degree of wear for chalking paint film is normal, reasonable, but the film's excessive erosion can cause severe chalking.

      Solution: First, use a hard bristle brush (on or masonry surface using a wire brush) the remaining powder compounds are clear as possible, and then take the water with a garden hose or power washer rinse thoroughly. After drying, the hand check for any remaining chalk on the surface.
      If there are visible chalk exist, coating quality 100% acrylic latex or oil-based primer (or similar sealant on masonry surfaces), and then re-coating quality exterior paint; if only a small amount or no powder residues, and the original paint intact, you do not need a primer.