Mildew

Exterior Paint Solution

 
 

Mildew: Mildew is the formation of brown, black or gray spots or blotches on the surface of paint or caulk due to the presence of fungi that feed on the paint film and other organic matter.

Possible Causes:

Damp areas that receive little or no direct sunlight (thus, such areas as walls with a northern exposure and the underside of eaves are particularly vulnerable).

Use of a lower quality paint with an insufficient amount of mildewcide.

Painting over a substrate or coating on which mildew is present.

Failure to prime bare wood before painting.

Solution:

First, make sure that the discoloration really is mildew, and not just dirt. Apply a few drops of household bleach to it, wait five minutes, then rinse. If the dark color disappears, the discoloration is probably mildew. Remove all mildew by scrubbing with a diluted household bleach solution (one part bleach, three parts water). Be sure to take the proper safety precautions -wear rubber gloves and eye protection. Leave the bleach on the surface for several minutes, then rinse. Next, thoroughly clean the surface with a detergent solution to remove dirt and other organic material on which mildew can feed. This can be done by hand or with a power washer. Rinse again. When the surface is dry, apply one or two coats of top quality acrylic latex paint -- this type of paint contains extra mildewcide and will resist mildew better than oil-based or alkyd paints.

 

Exterior Paint Problems & Solution


Alligatoring

Patterned cracking in the surface of the paint film resembling the regular scales of an alligator...


Blistering

Blistering is the formation of bubbles resulting from localized loss of adhesion and lifting of the paint film from the underlying surface...

 

Chalk Run down

Chalk Run-down: The washing down of chalk from an excessively eroding paint onto another area below (a brick foundation, for example), ruining its appearance...


Chalking

Formation of fine powder on the surface of the paint film during weathering, which can cause color fading. Although some degree of chalking is a normal, desirable way for a paint film to wear, excessive film erosion can result in heavy chalking...


Cracking Flaking

The splitting of a dry paint film through at least one coat, which will lead to complete failure of the paint. Early on, the problem appears as hairline cracks; later, flaking of paint chips occurs...

 

Dirt Pickup

Accumulation of dirt, dust particles and/or other debris on the paint film; may resemble mildew...


Efflorescence - Mottling

Efflorescence is the formation of crusty, white salt deposits, leached from mortar or masonry
as water passes through it...


Fading-Poor Color Retention

Premature and/or excessive lightening of the paint color, which often occurs on surfaces with sunny southern exposure. Fading/poor color retention can also be a result of chalking of the coating...


Frosting

A white, salt-like substance on the paint surface. Frosting can occur on any paint color, but it is less noticeable on white paint or light tints. On masonry, it can be mistaken for efflorescence see Efflorescence and Mottling...

 

Lapping

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

 

Nailhead Rusting

Reddish-brown stains on the paint surface...

 

Paint Incompatibility

 Loss of adhesion where many old coats of alkyd or oil-based paint receive a latex top coat...

 

Peeling

Spontaneous loss of ribbons or sheets of paint due to loss of adhesion. When the surface is coated with a primer and topcoat, or with several coats of paint, the peeling may involve all the coats, some of them, or just the topcoat...


Poor Galvanized Metal Adhesion

Paint that has lost its adhesion to a galvanized metal substrate...

Poor Alkali Resistance

Color loss and overall deterioration of paint film on fresh masonry...


Poor Gloss Retention

Deterioration of the paint film, resulting in excessive or rapid loss of luster of the top coat...

 

Surfactant Leaching

Concentration of water-soluble ingredients on latex paint, creating a blotchy, sometimes glossy appearance, often with a tan or brownish cast. More likely with tinted paints than with white or factory-colored paints...

 

Tannin Staining

 Brownish or tan discoloration on the paint surface due to migration of tannins from the substrate through the paint film. Typically occurs on "staining woods", such as redwood, cedar and mahogany, or over painted knots in certain other wood species...

 

Vinyl Siding Warp

Warping or buckling of vinyl siding panels that have been repainted...

 

Wax Bleed

Stains that come from waxy substances in the reconstituted wood products used to make hardboard siding. When the substrate is painted, these staining substances bleed through the paint; they can even bleed through some ordinary primers, possibly causing dirt pickup, mildew and/or poor paint adhesion...

 

Wrinkling

A rough, crinkled paint surface, which occurs when uncured paint forms a "skin"...

 

Cleaning Painted Walls

No matter how much you take care of your walls and that they are recently painted, they do get dirty and dusty very easily. Here are some tips to clean walls painted recently and doors to give a new shine to your home without spending money...

 

 

 

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