Roof Decking Repair

[busterbrown]

I was up on the roof of my Bullet over the weekend cleaning and waxing the top of the front fiberglass panel. I noticed that one of the roof deck panels along the gutter's edge has popped up a bit (movement of about 3/8") as if a fastener or staple has failed to keep it tight on the truss.. The membrane is still intact but I think it's just a matter of time before the upward movement of this sheathing will tear the TPO membrane along the gutter's edge.

What are my best options for a quick but effective fix? Would it be feasible to just locate the supporting truss and secure the decking down with several screws right through the TPO membrane, following up with Dicor lap sealant and Eternabond tape over the penetrating screws?

I hate to pull apart the gutter from the roof's edge to gain bare access underneath the membrane, which BTW remains nicely glued to the deck. Disturbing the membrane in this fashion seems like I may be causing more trouble than what's needed.

Will be performing a fix this week as we have one more trip before she's put away for the season. Any advice on how to "re-secure" the deck board to the trusses is sure appreciated.

[FlyingAroundRV]

I have the same issue on my TT as well. What you suggest sounds like an effective solution. I will be interested to see what John and Chuckster have to contribute on this.

[JRTJH]

Here's my "opinion" on the situation, for what it's worth....

If the decking is lifted from the underlying truss, and I was looking for a permanent fix, I'd remove the side molding, pull back the TPO membrane, "GLUE" the decking to the underlying truss and use screws (not the factory staples) to secure the decking to the truss. After that is done, I'd leave the TPO open for enough time for the adhesive to cure and harden so any "outgassing" wouldn't harm the TPO membrane. Then reseal and reinstall the side molding.

The reason I'd do it that way is because screws through the TPO are probably going to back out with the vibration/flexing in the joint during towing. Usually the factory glues the OSB sheeting to the trusses and shoots staples (often far too many) into the structure to hold it in place until the glue dries. In the "hurry up world" of RV assembly, often the decking isn't dry before the TPO is applied and when pulled tight, the TPO (not the staples) pull the decking into position on the curved trusses. Once the trailer sits in the sun for a while, the TPO gets warm and stretches enough to allow the decking to lift slightly. If you really look closely at almost any RV, you'll find gaps and loose sheeting on almost every RV roof decking.

If it were me, I'd leave it alone if it's "a loose OSB sheet that's lifted a quarter inch and I can push it back down".... It's under the TPO, screwing it back down isn't a permanent repair, putting DICOR sealant on top of screws is a "waterproof fix" only as long as the DICOR is intact. If the screw starts backing out (and they probably will) the screw heads will push up on the DICOR, lifting it, stretching it and possibly breaking the seal at the edges. If that happens, you've got a direct path for water (under the DICOR, to the loose screw threads and wicking directly to the OSB/truss wood.

I'd leave it alone if it's "just a loose decking sheet" and watch it. As long as there's no damage to the TPO and no staples/screws pushing up on the TPO, I'd not attempt a temporary repair until a permanent problem is imminent.....