How To Fix RV Windows Before Your Summer Road Trip

“How To Fix RV Windows Before Your Summer Road Trip” was written by the Flex Seal Editorial Team.

Before heading off for lakeside camping or cross-country cruising, it’s smart to check the condition of your RV windows. Over time, seals wear down and small gaps appear, letting in water, dust, road noise, and pests.

Left untreated, those small issues can lead to bigger problems like mold, wall damage, and ruined upholstery. Thankfully, with the Flex Seal Family of Products™, sealing up your RV windows is a quick weekend project. And you don’t need to be a pro to do it right.

Read on to learn how Flex Seal Products can help get your RV road trip ready.

Materials Needed

Flex Paste® in a Cartridge
Flex Seal® Liquid
Flex Caulk® (Hybrid or Silicone)
Flex Glue® 4oz Squeeze Tube
Utility knife or scraper
Caulking gun (for Flex Paste Cartridge)
Putty knife or Flex Gap Filler tool
Clean, dry cloth
Paint brush
Protective gloves & eyewear

Note: Before using Flex Seal products, read all directions carefully and take proper safety precautions, such as being in a well-ventilated area and wearing protective gear while applying.

Steps

1. Inspect Windows

Start by checking for cracked caulk, loose trim, or signs of past leaks. Look around the interior and exterior of each window, paying special attention to corners, seams, and any areas that may have shifted during travel.

2. Clean the Area

Use a utility knife or scraper to remove old sealant or debris. Wipe the area thoroughly with a dry cloth to ensure a clean, dry surface.

Flexpert Tip: While some Flex Seal products can be applied to damp surfaces, clean and dry is best for maximum adhesion.

3. Reseal Interior Trim with Flex Caulk

Apply Flex Caulk (Hybrid or Silicone) where the interior trim meets the wall or window frame. The built-in Trigger Flow Nozzle™ provides precision without a caulking gun.

Flexpert Tip: Flex Caulk is available in either a Hybrid or Silicone formula. Flex Caulk Hybrid adheres to wet, dry, porous, and non-porous surfaces and can be painted over once dry. Flex Caulk Silicone works best on dry, smooth, non-porous surfaces and is not paintable.

4. Reattach Loose Trim or Panels with Flex Glue

For areas where trim is pulling away or paneling is loose, apply Flex Glue in our Easy Squeeze tube behind the surface. Hold in place for 10–30 seconds to allow the instant-grab formula to begin setting. Let it cure for 24–48 hours for maximum hold.

5. Seal Exterior Frame with Flex Paste

Use Flex Paste in a cartridge to apply a thick bead around the outer seams of the window, where the frame meets your RV siding. Smooth with a putty knife or gloved finger, pressing it into all gaps and seams.

Allow Flex Paste to dry to the touch (2–6 hours) before applying additional layers if needed.

6. Apply a Protective Coating with Flex Seal Liquid

Brush Flex Seal Liquid over the dry Flex Paste to create a strong, flexible top layer that seals out moisture and weather. Apply thin, overlapping coats, allowing each to dry for 3–6 hours. Full cure time is 24–48 hours.

Flexpert Tip: Flex Seal Liquid is designed to stretch, expand, and contract with your RV—ideal for long-distance travel and temperature changes.