The fallowing are common house paint problems.
Alligatoring:
When failure accurse in the paint film it is called “Alligatoring” and takes on a cracking pattern of deep relief resembling a reptile's skin, such as that of an alligator or soil drote.
Causes:
• A second coat of paint was applied over a first coat of primer, incompatible paint such as oil paints or paint base coat before it dried.
• Oil based paints aging or due to fluctuations in temperature.
Repairs:
• Remove old paint, sand, prime and re-paint with flexible latex based paint.
Blistering:
Paint blistering is identified by bubbles that are small to medium sized or blisters that appear under the paint film.
Causes:
• Painting under direct sunlight, high humidity or on a hot surface which will trap solvent vapor as the paint dries too quickly.
• Painting when wood is damp causing trapped moisture to expand the paint.
• House moisture due to improper house ventilation.
Repairs:
1. Scrape away bubbled paint and sand.
2. Prime and paint in non-direct sunlight and non-humid condition.
3. Use high quality latex paint.
4. If due to lack of home ventilation, corrective repairs and sometimes renovation must be made to properly ventilate the house walls.
5. Check and repair any loose or missing caulking around windows and doors.
Chalking:
Chalking can be identifiable as a fine chalky powder that forms on the surface of a paint area, barring in mind that some chalking is a normal way paints self clean when exposed to the sun and rain but excessive chalking can be a paint failure and if chalking gets severe it may run off onto and stain surrounding construction.
Causes:
• Use of cheap quality exterior paint.
• Improper paint was used in an exterior application.
• Not applying correct paint quantity.
• Not properly sealing a porous surface before painting.
Repairs:
1. Any chalking is considered dirt and for that must be removed before re-painting.
2. Can be removed by power washing or scrubbing with a trisodium phosphate cleaning solution and rinse with clean water.
3. Let dry and paint with a high quality house paint.
Checking:
Checking is a failure in the paint film but is less severe then alligatoring and is characterized by long cracks in the paint film. Occasionally checking may become severe in some areas and a deeper crack or split in the paint will occur.
Causes:
• Natural aging of several layers of older paint.
Repairs:
• Remove old paint, sand, prime and re-paint with flexible latex based paint.
Efflorescence - Mottling:
Efflorescence is a problem of painted masonry and is identifiable by crusty white salt deposits that bubble through the paint film from a masonry structure. Salts in the brick or concrete become dissolved with water and then leach to the surface as the water evaporates.
Causes:
• Poor paint surface preparation where prior efflorescence was not entirely removed and washed before the surface was repainted.
• Heavy moisture.
• Inadequate waterproofing allowing ground water penetration.
• Painting masonry construction before the concrete or mortar had adequately cured and dried out.
• Cracks in masonry wall or poor pointing has allowed water to get behind masonry wall.
Repairs:
1. Eliminate any source of moisture by properly pointing any cracks or missing mortar in the wall or patching concrete with a latex concrete patch, clean out gutters and check windows and doors.
2. If moisture is migrating through the wall apply waterproofing to outside of wall, this should have been done when the property was built and done up to British standards.
3. Remove all efflorescence and loose flaking, chalking paint with a wire brush, scraping or power washing before repainting.
4. Clean area with a trisodium phosphate cleaning solution and rinse with clean water.
5. Let completely dry and paint with a high quality house paint.
Paint Yellowing
Development of a yellow cast in aging paint; most noticeable in the dried films of white paints or clear varnishes.
Causes:
• Oxidation of solvent based paint or varnish.
• Heat from ovens, radiators and heating ducts.
• Lack of light (e.g., behind pictures or appliances, inside cupboards, etc.).
Repairs:
• Top quality water-based paints do not tend to yellow nor does non-yellowing varnish. Solvent-based paints, because of their curing mechanism do tend to yellow and particularly in areas that are protected from sunlight.
Burnishing
Increase in gloss or sheen of paint film when subjected to rubbing, scrubbing or having an object brush up against it.
Causes:
• Use of matt paint in high traffic areas, where a higher sheen level would be desirable.
• Frequent washing and spot cleaning.
• Objects (furniture, for example) rubbing against the walls.
• Use of lower grades of paint with poor stain and scrub resistance (see Poor Stain Resistance and Poor Scrub Resistance).
Repairs:
• Paint heavy wear areas that require regular cleaning (e.g., doors, window sills and trim) with a top quality water-based paint, because this type of paint offers both durability and easier cleaning capability. In high traffic areas, choose a satin or gloss rather than a matt sheen level. Clean painted surfaces with a soft cloth or sponge and non-abrasive cleansers; rinse with clean water.
Paint Fungal:
Black, grey or brown spots or areas on the surface of paint or sealant.
Causes:
• Forms most often on areas that tend to be damp, or receive little or no direct sunlight (e.g., bathrooms, kitchens and utility rooms).
• Use of a solvent based paint or lower quality water based paint.
• Failure to prime bare wood surface before applying the paint.
• Painting over a substrate or coating on which fungal contamination has not been removed.
Repairs:
• Test for fungus by applying a few drops of household bleach to the area, if it is bleached away, the discoloration is probably fungus.
Remove all fungus from the surface by scrubbing with a diluted household bleach solution (one part bleach, three parts water) or a fungicidal wash, remember to wear rubber gloves and eye protection and then rinse thoroughly.
To protect against paint fungal contamination use a top quality water based paint and clean when necessary with bleach/detergent solution. Consider installing an exhaust fan (which is connected to a light switch) in high moisture areas.
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