Professional Painting Contractor Serving Mission Viejo and Surrounding Areas Since 1997 | Custom Coatings and Finishes | Team CCF
Common Paint Problems
Blistering is the formation of bubbles or pimples on the painted surface. There are two main types of blisters: those caused by heat and those caused by moisture.
Painting in direct sunlight on a surface that is too warm causes heat blistering. The film dries too rapidly, and traps solvents later vaporized, bringing pressure against the topcoat creating blistering. This is more common when using a dark color coating, since darker colors absorb the heat more readily than light ones.
Blistering can be caused by moisture, particularly in winter months. Interior moisture in tightly constructed homes is a major cause of exterior paint blistering. Moisture bubbling up inside the house escapes through the walls because there is no place else for it to go. In the summer, the sun heats the siding, and the water trapped behind the paint film is vaporized. The resulting pressures cause blistering.
The use of alkyd or oil paint finishes in extremely humid environments that have widely ranging temperature variations can also cause blistering. Alkyd finishes are sealer-tight finishes that will not allow moisture to vaporize and escape through the siding's surface film rapidly.
First, determine which type of blistering you have. Break open one of the bubbles. If bare wood shows, the blister was probably caused by moisture. If another layer of paint shows, a heat blister is the likely culprit. In either case, sand and scrape peeling paint to bare wood, prime exposed areas, and repaint. If large areas of the painted surface have blistered and need to be removed high-pressure washing or the use of a heat gun will speed the removal process.
In heat blistering the prime coat is generally not effected, and you can repaint, without priming, when the sun is not shining directly on the surface.
If the blistering was caused by moisture, a number of solutions exist. Repair loose caulking and install vents or exhaust fans if necessary. If the home has lapsiding, siding vents can be installed under the siding in areas where blistering has occurred. This will allow moisture from the inside of the house to evaporate before penetrating the wood siding, solving future blistering problems.
If the entire house is reprimed but stands without the finish coat for an extended period of time, more blisters may develop. These should be scraped smooth and spot primed before applying the finish coat.back to top
Alligatoring is the condition of paint film where the surface is cracked and develops an appearance similar to alligator skin.
Alligatoring is often caused by the inability of the topcoat to bond smoothly to the glossy coat beneath it. A glossy finish is too hard to provide a good bond. In the reverse, application of an extremely hard coating over a soft primer can result in alligatoring.
Further causes of alligatoring are not allowing sufficient time for the under coat to dry before recoating, the application of excessive coats of paint, and weathering.
Remove old paint completely by scraping and sanding. Removal of large areas can be done quickly by power washing or with the use of a heat gun. Prime with either a high-quality latex or oil primer, and paint with either oil or acrylic latex house paint.back to top
Brush marks are marks of brush that remain in the dried paint film.
Brush marks in dry paint film are often due to poor quality applicators. If the polyester or nylon filament of a brush is not finished properly, it will leave marks. Other causes include a too-porous surface that absorbs too much coating, excessive brushing, applying too little paint, using the wrong type of thinner, or not allowing enough drying time between coats. Brush marks will also occur in paint films that dry too rapidly.
Always use top-quality applicators. Brushes should contain tapered bristles properly flagged and tipped.
Smooth surfaces by sanding before repainting, or the brush marks will show through the new coat. If the surface is porous, a primer should be applied before painting. Be sure to use a recommended thinner if the coating is too thick and allow the paint to dry completely between coats.back to top
Cracking is a paint failure characterized by breaks and irregular lines wide enough to expose the underlying surface.
Cracking and flaking are advanced stages of checking. On surfaces that have received numerous coats of paint, the underlying layers lose their elasticity and are unable to expand and contract with the surface as it responds to temperature and humidity changes. As the wood swells, stress breaks the bond between layers to form checks. Additional swelling widens the breaks to form cracks. Because wood expands to a greater extent between grain lines, more force is exerted across the grain. Cracks are therefore more likely to form with the grain.
If the surface is plywood or flat-grained wood, the material itself is likely to crack eventually, which causes the paint film to crack also. Finish coats for plywood should, at a minimum, be 100% acrylic latex, but elastomerics (polyvinyl) may be the best for all plywood. If cracking of plywood joints is severe, caulk the joints with a good grade of acrylic latex or elastomeric type caulking. This prevents further moisture from penetrating the laminations of the plywood. Failure to adequately prime and protect pressed-composition boards and siding can also result in cracking.
Cracking down to the wood usually requires the complete removal of the coating, repriming, and repainting. In cases where cracking is occurring over plywood, there is not much you can do about it besides periodic scraping, sanding, repriming, and recoating. Latex paints usually fill plywood cracks better than oil-based materials. Try a latex exterior primer and a good grade of latex finish coat. Pressed-composition boards should be primed immediately following installation; an adequate coating should be kept on the surface at all times to seal out moisture.back to top
Cratering is the appearance of small depressions in dried paint film.
Cratering is caused by pockets of air or entrapped solvent in the wet paint film. These depressions can occur during application. In the case of solvent entrapment, they can occur shortly after the immediate coat or topcoat has been applied over the primer coat. They can also result from top coating a solvent-based product too rapidly, using a new roller cover without proper preparation, over shaking the paint, or painting in excessively high temperatures.
Craters should be sanded out and the surface repainted. If they are not removed before the new coat is applied, they will show through. Before using new roller covers, immerse them in the paint and roll them out a few times to expel air. After a can has been shaken, it should be left to sit until all the bubbles and foam disappear.
Sometimes when painting on a hot day, the coating will dry too quickly and prevent the bubbles from flowing out during application. If this occurs, try adding a small amount of thinner to the paint.back to top
Shedding of bristles can be caused by poor manufacturing of the applicator. Either the bristles were anchored improperly to the ferrule, or cheap bristles were used during the manufacturing process. Improper cleaning of the brush after previous use also causes shedding, and excessive brushing of overly thin paint is another cause of shedding.
Choose brushes from the top of the manufacturer's line. Thin paint only as indicated on the label.back to top
Mildew is one of the most common and persistent causes of house paint failure. Mildew is a mold that grows on many types of surfaces. The most important contributing growth factor of mildew is moisture. It's usually found in damp, dark areas, however, mildew is airborne and can grow anywhere.
Mildew is not caused by paint and mildew-resistant paints are only as effective as the surface preparation done prior to painting. Mildew must be removed before painting or the mildew will grow right through the paint film. Since mildew looks like dirt, first verify to see if mildew is actually present.Testing for mildew: Where mildew is suspected, drop a little household bleach on the surface. If it's mildew, the bleach will whiten it. If it's dirt, nothing happens.
Washing surfaces with a 50/50 bleach-water solution is recommended for cleaning surfaces, both bare and painted, containing mold, mildew, algae, and dirt.back to top
This situation is an industry-wide issue. Latex paints tinted to dark colors, especially in the deep tone and deep rustic bases, where a great deal of colorant must be added, take longer to cure completely. If a heavy rain or dew occurs before an adequate cure time, white streaking can appear. In some cases, the streaking is the surfactants coming to the surface. Depending upon the degree of exudation, it may appear that the paint has washed away.
Wash the area with warm water. Light scrubbing may be necessary. The white streaks will disappear and the coating will reappear intact.
Another condition, blistering, could also occur on insufficiently cured latex paint. What happens is the water gets behind the paint film where it is still curing and blisters begin to pop up.
Do not disturb the blisters. The blisters will recede as the water makes its way through the paint film to the surface.back to top
Surfactants exuded from a paint surface appear as dark stains and sheen variance.
Sudden temperature drops and heavy dew formation, prevalent especially in the spring and fall, can cause rapid surfactant exudation. Surfactants are surface active agents or “chemical soaps” which are vital components of all latex paints.
Due to the natural aging process of exterior latex paints, some of the surfactant material will exude or migrate to the surface of the film. Under normal conditions, the surfactants gradually reach the surface and then they are usually washed or weathered away uniformly.
When the exudation process occurs rapidly, the surfactants become concentrated on the surface. Paints applied under relatively cool and moist conditions, which are followed by dropping temperatures and rising humidity or the formation of dew during the drying time of the paint, can allow a large amount of the solubles to be brought to the surface at one time, in relatively high concentrations where they can form stains.
Typically surfactant exudation is a temporary situation. Sufficient rain or weathering will flush away most surfactant staining in time. Surfactants on latex coatings can be removed easily with water. Alkyd modified latex paints present a more difficult situation. Unless the surfactant exudation is removed immediately (within a couple of days), then it can only disappear slowly through weathering.
The loss of surfactants is natural and is in no way detrimental to the film quality or its performance.back to top
Many paint manufacturers concur that one of the causes of discoloration seen on painted hard board siding is “ wax bleed”. Wax or petroleum is used in the manufacture of hard board siding to make the board more moisture resistant. Under certain conditions, wax can migrate to the surface thereby causing a “ wetting” effect, which alters the appearance of the paint film.
Direct sunlight, particularly in southern and western exposures, can accelerate the migration by heating the wax allowing it to become more fluid and more mobile. As you would expect, dark, heat-absorbing colors will also accentuate this condition.