Staff Answer
May 12, 2026 - 10:27 AM
For your Toyota Winnebago Micro Warrior project, the Dicor DiFlex II membrane could be a good choice because it stays flexible and conforms well to older RV roofs.
For the adhesive, Dicor recommends their water-based bonding adhesive for wood substrates like plywood or luan. The common products are 901BA or 917BA.
For the adhesive, Dicor recommends their water-based bonding adhesive for wood substrates like plywood or luan. The common products are 901BA or 917BA.
For their roof size:
- 7 ft x 18 ft = about 126 sq ft
- You should plan on roughly 2 gallons minimum
- 3 gallons is safer for full coverage and edge work
A few suggestions for their roof rebuild:
Roof decking
The 3/8" smooth plywood is a solid upgrade if the original luan is damaged or soft.
Typical Toyota RV roof structure is often:
- Aluminum tubing framework
- Foam insulation
- Thin luan decking
- Aluminum or membrane outer skin
If the framing is still solid:
- You can xxxx the new plywood into the aluminum framing using self-tapping screws
- If the original luan underneath is still bonded well and dry, you may also glue and xxxx the new plywood over top
Construction adhesive compatible with foam should be used carefully, avoid solvent-based adhesives directly against styrofoam.
Folding over the sides
Yes — wrapping the membrane a few inches over each side is usually the best approach. Dicor’s retrofit guides mention pulling the membrane tight under side moldings/termination rails.
That helps:
- Prevent edge lifting
- Reduce chances of water intrusion
- Give a cleaner finished install
Installation tips
- Roll the membrane out in the sun first so it relaxes
- Apply adhesive with a short-nap roller
- Lay the membrane while adhesive is still wet/tacky
- Work from the center outward with a push broom if they don’t have a membrane roller
- Don’t stretch the TPO too tightly
Also to consider:
- Butyl tape under vents and edge moldings
- Self-leveling Dicor lap sealant around all roof penetrations
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