Minor Wood Rot Repair and Reseal on the Rear of the Old Cougar

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Over the 2021 summer months, I’ve been applying loads of TLC maintenance to our 10-year-old Keystone Cougar fifth-wheel trailer. Projects have included a new slide-out roof membrane, a new air conditioner gasket, coating of the main rubber roof, and reseal of the rear slide-out window.

Next on the to-do list? Repairing some minor wood rot and a complete reseal of the rear-end corner bead flashing. For the project, I decide to use several Alpha Systems sealant products from Lippert and a corner seal tape called Seal-Tite from Dicor.

Disclaimer: Love Your RV! received the Alpha Systems product samples free of charge from Lippert.

The bulk of the time was spent removing the metal corner flashing, cleaning up old sealants, and pulling out some broken screws and rusted staples. Prep work is always the biggest pain and time-consuming task. But yields a payoff in the end with a quality job that will last many years.

Removing the Flashing
Removing Metal Corner Flashing

Your mileage may vary depending on the surface so don’t take my word for it. Test a small area first. But, on my old trailer, I found a combination of mineral spirits, LA’s Totally Awesome cleaner, and Goo Gone Caulk Remover were helpful for surface prep. I was able to remove the old sealants without damage to the fiberglass siding or painted metal flashing. Other handy tools included plastic razors, a hive tool scraper, and a Scotch-Brite scrub pad.

Surface Prep Tools and Products

Removing Old Butyl Tape
Scraping Away Old Butyl Tape

The wood rot I mentioned took place on the very lowest corner section on the rear driver’s side of the trailer. I guess that water spray from the tires during wet travel days had forced rainwater into the area. A short wood 2X4 had partially rotted away. It was an easy fix. I cut a new one to fit using my hackzall and attached it in place using a thin metal plate.

Rotted Wood

New Wood

Next, I replaced any rusted-out, missing or loose staples with screws and applied the Seal-Tite seam tape to the corners. Then laid some Alpha Systems butyl tape inside the metal corner flashings and screwed them back in place.

Applying Seal Tite Tape
Applying the Dicor Seal-Tite Corner Tape

To finish up the job, I used some Alphabond roof seal tape on the very top corners where the corner flashing meets the roof and caulked all the flashing edges with Alpha Systems Non-Sag sealant.

Video Detailing the Rear End Repair and Reseal Job

I am glad I could get this job under my belt while the weather is sunny and warm. It’ll give me peace of mind come fall and the rains return. With these multiple layers of protection, it should be almost impossible for the corners to leak!

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Wood Rot Repair and Resealing the Rear End of the Old Cougar Fifth Wheel Trailer

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