The short answer
Inspect Before You Seal
Before you apply anything, look closely at the window from inside and outside. Check the caulk bead along the frame, the condition of the weatherstripping, and any gaps where water might sneak in. Heavy rain often finds weak spots that are not obvious during a quick glance.
Use a flashlight to inspect the corners and the sill. Feel for drafts on a windy day, and look for water stains or peeling paint on the wall below the window. Those signs point to where the seal has already failed. Fixing the right spots first keeps you from wasting effort on areas that are still sound.
Remove Old Caulk Properly
Old caulk that is cracked, brittle, or pulling away from the frame will not hold back heavy rain. Use a utility knife or a caulk remover tool to cut it out cleanly. Scrape the surface so it is smooth and clear of loose bits, then wipe it with a cloth and a mild cleaner to remove dust and grease.
Let the area dry completely before you apply new sealant. Even a thin layer of moisture can stop the new caulk from bonding. If you are working after a storm, give the frame a few hours of dry weather. Patience here makes the new seal last much longer.
- Use a stiff putty knife to scrape old caulk
- Wipe with rubbing alcohol or a window cleaner
- Let the frame air dry fully
- Check for rot or damage underneath
- Fill any deep holes with a paintable caulk backer
Choose the Right Sealant
Not all caulk works well for exterior windows. Look for a sealant labeled for outdoor use and able to withstand UV rays and temperature swings. Silicone or a hybrid polymer sealant often holds up better in wet, hot climates than basic acrylic caulk. Read the label to confirm it is paintable if you plan to paint over it.
For the bottom sill and the vertical sides, a flexible sealant is key. The frame expands and contracts with temperature changes, and a rigid caulk will crack under that movement. In rainy climates with heavy downpours, a durable exterior sealant is worth the small extra cost.
Apply Caulk and Weatherstripping
Load the sealant into a caulk gun and cut the nozzle at a 45-degree angle. Run a steady bead along the seam where the window frame meets the wall, and also along the joint between the sash and the frame. Smooth the bead with a wet finger or a small tool to press it into the gap and create a tight seal.
For movable windows, add weatherstripping along the top, bottom, and sides where the sash closes. Choose a type that compresses when the window is shut, such as foam tape or V-strip. This blocks wind-driven rain and also cuts down on drafts. Replace any worn strips before they fail during a storm.
- Apply caulk in one continuous bead
- Smooth it while it is still wet
- Use foam tape for the sash edges
- Press weatherstripping firmly into place
- Test the window opens and closes smoothly
Test and Maintain Your Seal
After the caulk cures (check the label for curing time), test the window by spraying it with a garden hose from outside. Aim the water at the top and sides, where wind drives rain hardest. Look inside for any drips or damp spots. If you find a leak, let it dry and add another bead of caulk to that exact spot.
Check your window seals once a year, especially before the storm season starts. Look for cracks, gaps, or peeling. Reapply caulk as needed to keep the protection strong. If you notice water stains on the wall or floor near a window, that could mean the leak is coming from the roof or the wall, not just the window.
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Call Now (386) 272-5697Frequently asked questions
Can I seal my windows from the inside only?
Sealing from the inside can help block drafts and minor leaks, but it will not stop water that is driven into the frame by heavy rain. The exterior seal is the main barrier. For good results, apply caulk and weatherstripping on the outside, and use interior sealant only as a temporary fix.
How long does window caulk last?
Most exterior caulk lasts about 5 to 10 years, depending on the material and weather exposure. In a humid coastal climate like Daytona Beach, UV rays and salt air can shorten that lifespan. Check your seals once a year and reapply when you see cracks, gaps, or peeling.
What if water still comes in after I seal the window?
If you have sealed the frame and weatherstripping and water still appears, the leak may come from the roof, siding, or a flashing issue above the window. Inspect the area around the window for missing shingles or damaged siding. If the source is unclear, call a local water damage pro to inspect and find the true entry point.