Paint Problems With Exterior Crackling on Wood

Normal Crackling

• A paint job will not last forever. Over time, the paint naturally breaks down, becomes harder and less flexible. It simply cannot withstand the stresses of the wood expanding and contracting with temperature and moisture changes in the environment. As a result, crackling appears. In this case, you can either accept the antique look of the wood or refinish it. Keep in mind that older paint may be lead-based and use proper precautions when sanding or removing the paint.

Wet Undercoat

• Painting over a primer or basecoat before it has adequate time to dry can also cause crackling. In fact, that's how most antique finishes are created. Paint cans list a "recoat time" which lists the amount of time paint needs under normal conditions to dry. For paint, normal conditions mean that the temperature is between 50 and 85 degrees Fahrenheit and the humidity level is below 50 percent. Lower temperatures and high humidity slow down the drying process, which means you need to wait longer than the recommended recoat time to avoid crackling.

Paint Dried Too Quickly

• New paint is a little bit like a vampire, it doesn't do well in direct sunlight. It also doesn't do well when the temperatures are above 85 degrees. Both conditions cause the solvent in the paint to evaporate too quickly. This can cause the top coat to shrink and crack as the rest of the paint dries.

Oil over Latex

• Oil-based and alkyd paints are very rigid. They are not as flexible as latex and water-based paints. This is why you can use latex paints over oil-based paints but you can't do the reverse. The oil-based paint is unable to bend the way latex paints do and ends up crackling.

Correcting the Problem

• Unfortunately, once paint crackles the only way to correct the problem is to sand or strip the old paint and repaint the item. If the crackling is in one area, you can scrape or sand the paint down to the wood and feather-sand the area between the bare wood and painted area. Remove any dust with a vacuum or tack cloth. Then, repaint the wood with a high-quality oil-based primer and exterior latex paint.