Most RV side windows clamp through the wall: a flanged frame on the outside, a clamp ring screwed to it from inside, and butyl sealant between the flange and the sidewall. That means a leaking window is often a resealing job rather than a new window, and a full swap depends on your wall thickness as much as the opening size.
RV Window Replacement: Measuring, Frame Types and What You Can DIY
At a glance
- Leaks first: builders treat the sealant between frame and sidewall as a wear item and tell you to inspect it every three to six months and reseal, not replace the window.
- Measuring: order from the window maker's own measuring guide, because a clamp ring window is sized to the wall thickness too.
- Exit windows: if the window is your emergency escape window, the replacement has to keep the red handles, the red EXIT label and the opening size the RV safety standard requires.
On this page (8)
Can you replace just the glass?
Some parts can be swapped without pulling the window. Lippert publishes bulletins for replacing an 8800 Series vent sash track, exit latch or pull rail on its own, listed in its 8800 Series documentation index. For a cracked pane or a fogged dual pane unit, call the window maker with your series and part number, or an RV glass shop, before you buy anything.
How do I measure for a new window?
Use the maker's measuring sheet, not a tape measure and a guess. Lippert's is QR-218, Measuring for a Replacement Lippert RV Window; request it from Lippert or your dealer.
Tip: A clamp ring window is sized to your sidewall thickness as well as the cutout, so two rigs with the same opening can take different windows.
Can you do it yourself?
A full swap takes two people: one unscrews the clamp ring inside while the other holds the frame outside, then you clean off the old butyl and bed the new frame. No window maker publishes fitting as an owner procedure, so if unsure, use the maker's dealer network or an RV service shop. A badly bedded frame leaks into the wall where you cannot see it.
Why is my window leaking?
Usually the sealant or loose screws. Keystone's owner's manual says the sealant between frame and sidewall deteriorates, and asks for an inspection every six months for gaps, cracks and shrinkage. Winnebago's towables manual checks it every three months and adds that window screws work loose and should be tightened.
Some water is normal: Jayco says a vent window may let water into the frame's lower track in heavy rain or while driving. Water at the top of the window or staining above it points upward: check the roof seams and slide-out seals on the same walk around.
Resealing the frame
Reseal when sealant squeezes out of the joint, cracks, peels or shows voids.
- Remove the excess with a plastic scraper.
- Clean the areas with mineral spirits and clean rags.
- Let everything dry, then apply the sealant your dealer says your rig uses.
Windows are bedded in butyl. Dicor's butyl seal tape goes on clean, dry surfaces between 30°F and 110°F, cut to length and laid without stretching. With fasteners, Alpha's Q130 gasket tape goes on the entry side to keep contaminants out of the fastener holes.
Tip: Do not seal the bottom flange. Winnebago leaves two deliberate voids in that sealant so water behind the frame can drain out. Closing them traps it in the wall.
Exit windows are not ordinary windows
If you are replacing the emergency exit window, the new one must still work as an exit. NFPA 1192, in the 2021 text reproduced in an NFPA public input report, requires that it:
- opens by hand from inside, with no key or special tool;
- takes no more than 20 lb of force to open;
- has its bottom 36 in. or less above the floor;
- gives an opening that passes the standard's 24 in. by 17 in. ellipse test;
- carries an EXIT label in red letters at least 1 in. high;
- has red handles on anything you must operate to open it.
The 2026 edition was reorganized, so confirm the wording before citing a section number. Open and close the exit window each trip so the seals do not stick (Grand Design), and never cover or block it (Forest River).
Check your window against the recalls
Two recalls of Lippert windows are worth a part number check. NHTSA recall 20E-039 covers vent adhesion on certain 3000 Series windows, with replacement vents fitted on the unit. Thor Motor Coach's bulletin for recall 21V-522 covers 6400 Series vents built between October 2018 and August 2020 at a Michigan plant formerly run by Hehr International, so Hehr 6400 Series windows are now Lippert products.
Tip: Have your coach's year, model and window series ready; the recall documents list the covered part numbers.
Common questions
Can you replace an RV window yourself?
The upkeep is owner work. Forest River asks owners to adjust and lubricate window latches and moving parts once a year, and to keep the vinyl seals clean and flexible with a silicone spray or lubricant.
Should I replace the whole window or just the glass?
Sometimes only a part needs replacing: on an escape window even the seal tape is its own part. Lippert lists TI-332, 8800 Series Exit Window Foam Tape Replacement, separately from the window itself.
How do I find out who made my RV windows?
Check the component manufacturer warranty table in your owner's manual. Grand Design's 2024 Imagine manual, for example, lists Cleer Vision Windows and Lippert. Otherwise, call the builder with your VIN and model year.