How to Troubleshoot Interior Paint

Purchase high-quality paint. You can avoid many paint problems by buying the best quality paint you can afford. You'll help prevent mildew; cracking and flaking; foaming and cratering; brush marks in the finished paint surface; areas of denser color or glossier finish; low resistance to scrubbing; painted surfaces that stick together (blocking); deep, irregular cracks in paint (mud cracking); roller marks; and poor resistance to stains

Purchase semi-gloss or gloss paint for high traffic areas, or locations that will require frequent cleaning, to prevent excessive paint wear.

Purchase the right type of roller for the paint you are applying and the surface you are painting. Use a low-nap roller for semi-gloss and gloss paint to prevent bubbles and craters. Use a low-nap roller when painting drywall to prevent a textured finish.

Purchase high-quality brushes to avoid leaving brush marks.

Apply paint when the temperature is 65 to 85 degrees Fahrenheit, and when humidity is moderate. Painting when the temperature is too low can cause paint to crack or droop downward. Painting under high humidity conditions can cause blisters to appear in the dried paint. Painting in hot, humid weather can cause paint layers to wrinkle. If you paint in high humidity, give the surface longer to cure or it may have a tendency to dent and imprint easily. Painting when it is very hot, dry and breezy may cause deep cracks in paint.

Treat mildew--which appears as gray, brown or black spots on the paint--with a solution of three parts water to one part household bleach. Wear gloves and eye protection. Let the solution sit for 20 minutes then use a stiff brush and water to scrub the surface clean. Repaint only after all mildew has been removed. To prevent the problem from recurring, consider installing an exhaust fan in high humidity areas; avoid using any oil-based product or an inexpensive latex paint; and immediately remove mildew with a bleach and detergent solution before it can stain paint.

Clean surfaces before painting. Use a household detergent for mildly soiled surfaces, and tri-sodium phosphate for greasy or heavily soiled surfaces. Rinse the surface thoroughly and allow to dry. Paint will not adhere properly to dirty surfaces.

Sand surfaces with 180- or 200-grit sandpaper prior to painting to help prevent flaking and peeling of paint. This is especially important if the surface you are painting is semi-gloss or shiny. Remove all sanding dust with a tack cloth or damp rag.

Prime unpainted surfaces to prevent cracking and flaking. Prime porous surfaces before painting to prevent uneven sheen. Prime previously painted surfaces when applying gloss or semi-gloss paint to prevent bubbles forming in the paint. Use a stain-blocking primer for stains, marks or wood resin that may bleed through your topcoat.

Tint your primer when painting a dark color over a light color. This will minimize the likelihood that the old paint will show through.

Dampen your roller slightly before applying latex paints, but never use a wet roller or you will see roller marks, paint spatters and other undesirable textures in the paint.

Roll or brush paint smoothly and evenly to prevent making bubbles in the paint, which will pop and make bumpy craters on your finished surface. Do not shake a partially-filled can of paint or excessively brush or roll the paint. Both of these may create bubbles.

Apply paint without thinning it to avoid flaking and sagging of paint. Thinned paint will also cause the old paint color to show through.

Apply paint in two or more thin coats. Applying paint thickly can cause "mud cracking," or deep irregular cracks in the dried paint. It can also cause the paint to "sag" or drip. Using an overloaded roller or overworking paint can cause paint to spatter.

Allow paint to dry fully before adding additional coats to avoid cracking.

Stir paint frequently. This will ensure that the paint components are well-mixed and avoid areas of thinner paint and challenges covering an existing paint color.

Allow paint to fully cure. This will prevent objects leaving an imprint on the paint (poor print resistance) and stickiness when two painted surfaces are pressed together (blocking). Wash paint only after it has fully cured to avoid damaging the finish.

Discard paint that is more than a year old to prevent problems with foaming and cratering.