Mildew

Black, gray or brown spots or areas on the surface of paint or caulk.

Possible Cause :

• Forms most often on areas that tend to be damp, or receive little or no direct sunlight (e.g., bathroom, kitchens, and laundry rooms).
• Use of an alkyd or oil based paint, or lower quality latex paint.
• Failure to prime a bare wood surface before applying the paint.
• Painting over a substrate or coating on which mildew has not been removed.

Solution :

• Test for mildew by applying a few drops of household bleach to the area, if it is bleached away, the colorant is probably mildew
• Remove all mildew from the surface by scrubbing with diluted household bleach solution (one part bleach, three parts water), while wearing rubber gloves and eye protection.
• Rinse thoroughly
• To protect againts mildew, use a top quality latex paint, and clean when necessary with bleach / detergent solution.
• Consider installing an exhaust fan in high moisture areas.
  

Lapping

Appearance of a denser color or increased gloss where wet and dry layers overlap during paint application.

Possible Cause :

• Failure to maintain a " wet edge " when painting.
• Use of low solids " economy " paint.

Solution :

• Maintain an wet edge when painting by applying paint toward the unpainted area and then back into the just-painted surface. This technique (brushing or rolling from " wet to dry " rather than vice versa) will produce a smooth, uniform appearance. It is also wise to work in manageable-size area ; plan for interruptions at natural break, such as a window, door or corner.
• Using a top quality acrylic latex paint makes it easier to avoid lapping problems because higher solids (pigments and binder) content makes lapped areas less noticeable.
• If substrate is very porous, it may need a primer / sealer to prevent paint from drying too quickly and reducing wet edge time.
• Alkyd paints generally have superior wet edge properties.
  

Cracking / Flaking

The splitting of a dry paint film through at least one coat as a result of aging, which ultimately will lead to complete failure of the paint. In its early stages, the problem appears as hairline crack, in its later stages, flaking occurs.

Possible Cause :

• Use of lower quality paint that has inadequate adhesion and flexibility.
• Overthinning or overspreading the paint.
• Inadequate surface preparation, or applying the paint to bare wood without first applying a primer
• Excessive hardening and embrittlement of alkyd paint as the paint job ages.

Solution :

• Remove loose and flaking paint with a scraper or wire brush, sanding the surface and feathering the edges.
• If the flaking occurs in multiple layers of paint, use of a filler may be be nacessary.
• Prime bare wood areas before repainting.
• Use of a top quality primer and top coat should prevent a recurrence of the problem.
  

Foaming / Cratering

Formation of bublles (foaming) and resulting small, round concave depressions (cratering) when break in a paint film, during paint application and drying

Possible Cause :

• Shaking a partially filled can of paint.
• Use of low quality paint or very old lated paint.
• Applying (especially rolling) paint too rapidly.
• Use of a roller cover with wrong nap lenght
• Excessive rolling or brush of the paint.
  
• Applying a gloss or semigloss of the paint over a porous surface.

Solution :

• All paint will foam to some degree during application, however, higher quality paint are formulated so the bublles break while the paint is still wet, allowing for good flow and appearance.
• Avoid excessive rolling or brushhing of the paint or using paint that is more than a year old.
• Apply gloss and semigloss paint with a short nap roller, and apply an appropriante sealer or primer before using such paint over a porous surface.
• Problem areas should be sanded before repainting.
  

Caulk Failures

Loss of caulk's initial adhension and flexibility, causing it to crack and / or pull away from the surfaces to which it is applied.

Possible Cause :

• Use of ower quality caulk.
• Use of wrobng type of caulk for particular application (e.g., using latex or vinyl caulk in area where there is prolonged contact with water or considerable movement of the caulked surfaces).

Solusion :

• Use a top quality water based all acrylic or siliconized acrylic caulk if prolonged contact with water is not anticipated.
• These caulks are flexible enaough toadapt ti minor fluctuations in the substrate, stretching in gaps that widen slightly over time.
• They also adhere to a wide range of interior building material, including wood, ceramic tile, concrete, glass, plaster, bare aluminum, brick and plastic - even in area where moisture is present.

Note : Silicon caulk should not be painted

Burnishing

Incrase in gloss or sheen of paint film when sbjected to rubbing, scrubbing or having an object brush up againts it.

Possible Cause :

• Use of flat paint in highly trafficked areas, where a higher sheen level would be desirable.
• Frequent washing and spot cleaning.
• Objects (furniture, for example) rubbing againts the walls.
• Use of lower grades of paint with poor satin and scrub resistance. (see Poor Stain Resistance and Poor Scrub Resistance)

Solution :

• Paint heavy wear areas that require regular cleaning (e.g., doors, window sills and trim) with a top quality latex paint, because this type of paint offers both durablility and easier cleaning capability.
• In high traffic areas, choose a semigloss or gloss rather than a flat sheen level.
• Clean painted surfaces with a soft cloth or sponge and non-abrasive cleansers, rinse with clean water.
  

Blocking

Undersirable stiking together of two painted surfaces when pressed together (e.g., a door sticking to the jamb)

Possible Cause :

• Not allowing sufficient dry time for the coating before closing door or windows.
  
• Use of low quality semigloss or gloss paints.

Solution :

• Use top quality semigloss or gloss acrylic latex paint. Low quality latex paints can have poor block resistance, especially in warm, damp conditions. Follow paint label instructions regarding dry times.
• Acrylic latex paints generally have better early block resistance than vynil latex paints, or alkyd or oil-based paints, however, alkyd develop superior block resistance over time.
• Application of talcum powder can relieve persitent blocking.
  

Blistering

Blubbles resulting from localized loss of adhension and lifting of the paint film from the underlying surface.

Possible Cause :

• Applying oil-based or alkyd paint over a damp or wet surface
• Moisture seeping into the home through the exterior walls (less likely with latex paint)
• Exposure of latex paint film to high humidity or moisture shortly aftrer paint has dried, especially if there was inadequate surface preparation.

Solution :

• If blisters do not go all the way down to the substrate : Remove blister by scraping and sanding, and repaint with a quality acrylic latex paint.
• If blisters go down to the substrate : Remove the source of moisture, if possible. Repair loose caulking, consider installing vents or exhaust fans. Remove blister as above, remembering to prime coat before applying the top coat.