Exterior 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.


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 Painting – Frequently asked questions

Can I paint over aluminum/vinyl siding?
Yes. Always make sure the surface is cleaned to remove any chalk or dirt. Never apply paint that is darker than the original painted surface on vinyl siding.

Do I need to wash my house before I paint?
Yes. Surfaces must be clean before painting. Thoroughly wash with a house cleaner and water solution, making sure to remove any and all mildew. Rinse and allow to dry.

How much paint do I need?
Be sure to utilize our Paint Gallon Calculator in the Project Planner section to help you determine how many cans to buy for your next project.

To achieve one-coat coverage, paint should be applied at a maximum of 400 square feet per gallon. Rough or textured surfaces may require more paint. On these areas allow for 25-30 square feet per gallon. Some bright colors may require multiple costs to achieve sufficient hide.

How do I apply the paint?
When using more than one gallon of the same product, mix the gallons together to insure color and sheen uniformity. Two coats of this paint will provide maximum protection.

How do I paint shingles & shakes?
Shingles offer natural breaking points, paint in a vertical direction.

How do I care for freshly painted surfaces?
We suggest not washing your newly painted surface for at least 30 days. After that time, dirt and stains may be removed using a mild, non-abrasive cleanser and water.

I have never painted the exterior of my home before….?
When painting the exterior of your home always start with a clean surface; paint one side of the house at a time, starting with the highest point; apply a full even coat to one side of the house at a time and always paint the trim last.

What conditions are best for painting my house?
Generally you should only paint when the surface is between 50F and 85F. High temperatures cause the water in the paint to evaporate too quickly, while low temperatures prevent latex from covering properly. Always avoid painting in direct sunlight, strong winds, or when rain is expected within 8 hours.

What tools do I need?
Depending on your project and the type of structure you are painting, paints may be applied with a nylon/polyester brush, a paint pad or spray unit.

What is the proper way to use spray equipment?
It is always safe to operate spray equipment with safety cautions. Use respiratory and eye protection. All spray units are different and it is important to follow the manufacturer’s instructions carefully.