What Causes Cracks Around Exterior Windows and Doors?

Cracks around exterior windows and doors are one of the most common things painters see, and one of the most important to fix. These joints are where water most often gets into a home's walls. When the paint and caulk there fail, rot and leaks are often close behind.

Why Cracks Form

Caulk ages. Caulk dries out and loses flexibility over time. Sun and heat speed that up. Once it hardens, it cracks or pulls away from the trim and siding.

Materials move. Wood trim, siding, and window frames expand and contract with temperature and humidity. Different materials move at different rates, which stresses the joints between them.

The house settles. Especially in newer homes, settling can open gaps around windows and doors.

Paint gets brittle. Old, thick layers of paint lose flexibility and crack along joints where trim pieces meet.

Moisture. Water that gets into a small crack can swell wood, make the crack larger, and cause paint to peel.

Where to Look

• The joint where window and door trim meets siding
• Miter joints at the corners of trim
• Window sills and the bottom of door frames
• The seam between trim and brick
• Above windows, where water runs down from the wall

Why It Matters

A small crack lets water in every time it rains. That moisture gets behind the paint and into the wood. Over time, it can rot sills, trim, and framing, and cause interior leaks. Repairs at that stage are far more expensive than resealing joints early.

How Cracks Should Be Repaired

1. Remove failed caulk completely, rather than caulking over it. 2. Check the wood for softness or rot and repair or replace damaged sections. 3. Clean and dry the joint. 4. Prime bare wood before caulking, where recommended. 5. Use backer rod in deep or wide gaps so the caulk can flex correctly. 6. Apply a quality exterior sealant that's flexible and paintable. 7. Paint over the caulk to protect it from UV and blend it in.

Remember that some gaps, like weep holes in window frames and the drip edge above flashing, are designed to let water out and shouldn't be sealed.

The STRIPES Takeaway

Cracks around windows and doors come from aging caulk, movement, settling, and moisture. Catching and properly resealing them is one of the most important parts of exterior maintenance and repainting.

Planning an Exterior Painting Project in Atlanta?

STRIPES PAINTING CO. paints and protects home exteriors throughout the Atlanta area, with careful prep and quality products. Contact us to schedule a free estimate.

STRIPES PAINTING CO. - Built on Detail.