What it is: Small to medium sized bubbles or blisters below the paint. This is most commonly seen in trim or wood siding.

Causes: When the paint was put on, it was on a hot surface or in direct sun making the paint dry too quickly. Or the paint was put on damp wood, and the water was trapped inside the paint. Along the same note, dew, rain or high humidity got under the paint film after it dried.

Fix: Get a flat scraper and scrape away the blister. Sand the area down to bare wood and let it completely dry before you move on. Sand, prime and paint in dry conditions and out of direct sunlight with a high-quality latex paint.

What it is: A cracking pattern resembling an alligator’s skin. Checking is a less severe form with long cracks. If left unattended, it can cause cracks and splitting in the paint.

Causes: Moving on to the next coat without letting the previous fully dry. The second coat of paint did not work with the first. For example, a glossy paint cannot be put over a latex paint. Oil-based paints run the risk of this through aging.

Fix: To fix this, you must completely remove the old paint and start over. Sand, prime and repaint with a flexible latex paint. The higher the quality, the less chance of this occurring again.

What it is: Mildew is a fungus that feeds on paint film or caulk. It usually shows as a brown or green blotch.

Causes: Moisture is the cause of mildew. It grows in dark, poorly ventilated, wet places. The underside of soffits and eaves are prone to growing mildew. If mildew is painted over, it will continue to grow. Bare wood without primer also makes a building ripe for mildew.

Fix: Scrub the area with trisodium phosphate cleaner or bleach with 1 part bleach to 3 parts water. Always wear eye and hand protection when working with these chemicals. Let the area dry for about 15 minutes, then rinse with clean water. Repeat the process. Allow adequate dry time and finish with a high quality latex exterior paint.

What it is: Probably the most common exterior house painting problem is droopy, dripping paint.

Causes: Too much paint applied at once or the paint was thinned too much. The weather was too cold making the paint thicker, or the humidity was too high. Primer wasn’t used or the area wasn’t cleaned before application.

Fix: If you see this problem while you are still working with the paint, use a brush or roller to redistribute the paint more evenly. If the paint has already dried, sand the area down to even. Repaint. Do not overload the paintbrush, and use two thinner coats rather than one heavy one.

Causes: This is a common issue that comes from moisture or poor adhesion. The difference is that paint is peeling from a previous layer versus peeling from the substrate.

Causes: The surface was wet, dirty or shiny. Underlying layers did not adhere. Blistering was not repaired or a low quality paint was used.

Fix: Scrape the peeling paint and sand affected areas. Spot prime the bare area you just made. Caulk as required and repaint.

What it is: Red or brown stains on the paint surface.

Causes: Nails without corrosion resistance were used to attach siding. Excessive weather has worn away galvanized heads on nails.

Fix: Find the offending nails and replace them with stainless steel or galvanized nails. If they cannot be removed, sand the head to bare metal and countersink them. Use a primer with a stain blocking and rust inhibiting factor. Caulk or fill the nail heads and sand smooth. Paint over.