[B]Professional looking caulk "window gaskets"[/B]

[aframedoctor]

There are three caulk-adhesive products I would recommend, having repaired trailers for about 5 years: Colorimetric, Silaprene, and GeoCell RV Pro Flex. I prefer the first two, though the ProFlex is fine also. Use the regular caulk-adhesive, NOT the self-leveling that is made for roof repairs as it "flows" for a long time. If used on anything but a horizontal surface it will flow right off or puddle at the bottom.

Apply like regular caulk for cracks, joints, etc. If using around a bubble window or roof vent, run a thick masking tape (or two layers of masking tape atop each other) around the edge of the item to be caulked. Place one strip about 1/2" farther out from the existing "gasket" of caulk. Place a second strip of masking tape inside the existing "gasket". You should now have two lines of masking tape 1" wider than the existing caulk "gasket" (1/2" on each side).

Apply the caulk-adhesive between the masking taped lines. All of these caulks are petroleum-based, so smooth them with a smooth (softer) paper towel or cloth saturated with mineral spirits or similar solvent. Do not over-work the caulk, just make it reasonably smooth. Allow 10-15 minutes for caulk to set up. Remove the masking tape slowly so as to not disturb your handiwork. If you wait longer the tape may be hard to remove & tear often due to film strength of caulk. Allow the caulk to set for several days without succumbing to the temptation to touch it; this caulk takes a little while to cure but remains flexible for years.

You will discover your hard work has resulted in a professional looking "gasket" that overlaps the original seal and provides additional protection. CAUTION: 1) Apply in a ventilated work area. 2) These are ADHESIVE-caulks, so removing them once they're cured is HARD to do without damaging your trailer! But the quality of this repair is excellent. 3) Clean-up requires petroleum-based solvents. 4) Wear disposable gloves while working with the caulk-adhesive.

[crocus]

I used the ProFlex to caulk every conceivable spot I could find that moisture might get in where it shouldn't.
Where the slide seals meet the camper side, especially the leading edges, could let a lot of water seep through when driving in the rain.
I also removed the vents to the propane tank storage lockers, as the holes are just cut through the wall, exposing the luan to the elements. Prime spot for the start of delamination!
Also tidied up the bottom of the fridge vent access panel hole, and put a complete new layer of ProFlex over the obviously cheap crap the factory used. Problems there have definitely caused wall delamination.
However, I didn't wait for the caulk to 'set up' before removing the masking tape. Seemed to work fine pulling it off with the caulk still wet.