Painting

How to Paint Exteriors

Fixing common paint problems

Most common exterior painting problems are the consequence of poor preparation. Paint adheres to clean, dry surfaces. For more information, see Prepping.


Here's the run-down on common exterior paint problems and solutions:

Problem Likely Causes Solutions

Algae

Algae is a common exterior paint problem

Airborne algae spores grow on continually wet surfaces in bright light conditions. Appears as green, red or brown film and can be difficult to remove.

Sand, scrape or abrasive pad, bleach & water solution (3:1). Prime with either oil or latex primer depending on requirements.

Alligatoring

Valspar Common Exterior Paint Problems Alligatoring

Like peeling, alligatoring is an adhesion problem. If latex paint was applied when the surface temperature was too cold, the paint doesn't get a good chance to form a stable film.

Sand off and scrape all the loose paint. Spot prime bare areas. Paint with a high quality exterior paint and follow all label instructions.

Blistering

Valspar Common Exterior Paint Problems

Blistering occurs when moisture is trapped under the paint usually as a result of high-humidity. Paint blisters can pop and peel.

Do not intentionally pop the paint blister. It may recover when it dries. Scrape away paint. Fill in and sand holes. Paint during dry weather. Ventilate high-humidity areas such as bathrooms.

Buckling

Valspar Common Exterior Paint Problems Buckling

When vinyl siding gets too hot, it can buckle and separate.

Don't paint vinyl siding with a color darker than the original siding color. Dark colors absorb heat. Sometimes siding can be re-adjusted and flattened. (Note: new siding installations frequently require some adjustment as all the pieces shift somewhat up on heating.)

Chalking

Valspar Common Exterior Paint Problems Chalking

When paint degrades in sunlight a loose powder appears on the surface. Using interior or lower quality paints on exterior surfaces will cause chalking. Rain can wash off chalk so you often see chalk on an exterior surface not protected by eaves.

Don't paint over the chalk. Wash off the chalk with TSP (Tri Sodium Phosphate) and water using a sponge. Rinse with clean water and allow to dry thoroughly. Paint with a high quality exterior product.

Checking

Valspar Common Exterior Paint Problems
  • 1. Poorly prepped or unprimed wood surface

  • 2. A second coat is painted over a first coat that isn't fully dry

  • 3. Too many layers of paint
 Scrape down to the raw wood, prep, prime, and paint.

Crazing

Valspar Common Exterior Paint Problems

Crazing is the result of two or more layers of incompatible paint.

Scrape back down to the original surface, prep, prime, and paint.

Drips and Blobs

Valspar Common Exterior Paint Problems

Paint drips are usually caused by sloppy technique, particularly overloading paint on rollers and brushes.

Let the paint dry. Sand it with fine grade paper. Clean off the dust carefully and repaint.

Fading

Valspar Common Exterior Paint Problems Fading

Light, heat or weathering can cause paints to fade. Some colors are more fade resistant than others due to their pigments. High quality paints are more fade resistant.

Clean the surface using TSP (Tri Sodium Phosphate) and water to remove chalky residue usually found on the surface. Apply a high quality 100% acrylic paint right over the top.

Flaking

Valspar Common Exterior Paint Problems
  • 1. Latex paint over a high-gloss surface

  • 2. Dirty, poorly-prepped surface

  • 3. Too many layers of paint
 Scrape back down to the original surface, prep, prime, and paint.

Lichens

Valspar Common Exterior Paint Problems Lichens

Lichens appear where prolonged moisture and light conditions exist. Any surface weathered to the point of lichen growth should be completely stripped and most likely replaced. The attachment roots, dirt, and sap combine together to stain paint coatings.

Scrape off and assess surface condition, Bleach solution, sanding, and wire brushing needed. Stain blocking exterior primer preferably oil based if staining is bad.

Mildew

Valspar Common Exterior Paint Problems Mildew

Mildew is a naturally occurring plant spore that will flourish in the right moisture and food conditions, and more often in shaded places.

Mildew must be removed using bleach and water prior to coating. Alkyd resin in oil paints and protein thickeners in latex are a food source for the spore. Eliminate the moisture problem. Use a primer and paint that resists mildew growth.

Peeling

Valspar Common Exterior Paint Problems Peeling

Peeling is caused by something on the surface between the substrate and the paint. Dirt, dust, mildew, residues from cleaners, improper surface preparation, and improper application can all contribute to peeling problems.

Prevention is your best move. Make sure your surface is clean and free of residual soaps. Remove any loose paint surrounding the area, test beyond the peeled edge to determine overall condition. Sand and feather using 120 grit paper and wipe clean. Prime bare wood with an exterior primer and re-apply the paint.

Wrinkling

Valspar Common Exterior Paint Problems Wrinkling

Development of ridges and furrows in a paint film during drying, caused by applying a very thick coat of paint. The top surface of the film dries faster than material underneath creating a pulling/shrinking action.

Sand thoroughly after allowing ample dry time. Coating may require other removal methods such as chemical stripping to reach original surface quickly.

Painting

Valspar Painting DIY

More information about proper surface preparation, and advanced techniques.

Prepping
Clean Up
Locate a store

Computer screens and printers vary in how colors are displayed. Colors which display on the screen and printed colors may not match the paint's actual color. Please visit a local retailer to view actual color samples before making a final selection of a paint color.

Copyright © 2009 Valspar. All Rights Reserved.