View Full Version : Roofing Question

09-04-2021, 05:53 AM
Went to inspect the roof this morning. Found some screws or nails beginning to poke through. Before I slit the covering and then secure them a few questions for those who've done this before.

One photo shows the whole length of the roof. It appears that the edge is a curved piece that is separate from the majority of the flat surface. True?

Once I slit the roofing material and secure the screws or nails, what sealer should I use to cover the slit in the roof?

09-04-2021, 06:00 AM
I'm sure others will chime in but,... for the sealant I would use Dicor.

09-04-2021, 06:04 AM
No need to slit the roof. Just remove the side rail and then you can peel back the membrane enough to repair the "hip".

09-04-2021, 07:31 AM
I agree with Chuck. Any time you cut or penetrate the roof membrane, you set up a "perfect storm for leaks". Sealant, whether it's DICOR sealant or tapes such as Eterna-bond, can have adhesive failure and form channels under the sealant to direct water to any hole or cut in the membrane. That's why we do 90 day or 180 day "roof inspections": Because the sealants aren't perfect at protecting the surfaces they're applied to and often, depending on circumstances, they aren't even great at protecting your roof.....

It's much better to remove the side trim, pull the membrane up and away to gain access, then apply adhesive to reattach the membrane to the surface and reinstall the side trim.

Looking at your photos, it appears that several screws in the same general vicinity appear to have backed out. Typically, "all the screws in one area" backing out is not a normal occurrence. I'd believe there's an issue with the roof decking in that area. Either it's been wet and is soft/rotted or the "OSB flakes" have separated... To not see any other screws backing out along that entire side would give me a very good reason to carefully inspect that part of the roof structure. I'd suspect there's a lot more going on under the membrane than 3 or 4 "loose screws"..... That's another reason to approach it from the side. You can keep removing side trim and enlarging the work area by just expanding the distance by removing more trim. If you approach it by cutting the membrane, you'll keep destroying larger and larger parts of the membrane and making even greater potential for sealant failure to occur.....

I'd stick with a "side approach" .....

09-04-2021, 07:57 AM
I agree with Chuck and John. There appears to be a "repair" area with a large amount of dicor (looks like) on the front (rear?) edge in the first 2 pics. That's also where the strip of elevated screws are; sort of goes along with John's observations.

09-04-2021, 12:34 PM
Well, isn't this just a kick in the teeth!

"I'd believe there's an issue with the roof decking in that area. Either it's been wet and is soft/rotted or the "OSB flakes" have separated... To not see any other screws backing out along that entire side would give me a very good reason to carefully inspect that part of the roof structure. I'd suspect there's a lot more going on under the membrane than 3 or 4 "loose screws".

I'm a fairly good woodworker and I should have thought of that, duh. Thanks for pointing it out.

This is at the right rear of the coach and there has been a prior repair (prior owners) on the rear side of the corner. This is about 15 inches in on the passenger side.

The "side trim" that several of you mentioned - is this the rain gutter? Haven't gone back up the ladder yet but from ground level it appears the gutter is the only thing attached to the side wall immediately under the rood.

09-04-2021, 12:42 PM
Remove the vinyl insert and you should see lots of screws. They are most likely #2 Robertshead. There should be putty/butyl tape on the backside so you should get enough to replace it.

Once the rail is off the roof membrane is probably stapled, carefully remove those and your golden.

09-04-2021, 12:54 PM
Remove the vinyl insert and you should see lots of screws.

So just to be sure I understand, the gutter has a vinyl insert that covers the screw heads? I have seen that done before.

09-04-2021, 01:33 PM
The gutter trim will look something like these photos. Remove (and discard) the vinyl trim insert. It's cheap, seldom goes back in and stays, and is much harder to reuse if it's old and brittle. Once the insert is pulled off, you'll see the screws. Remove them (PAY ATTENTION TO WHICH ONES ARE RUSTED as they will give you an idea of what is going on under the trim) and carefully pry/pull the trim away from the trailer sidewall and roof membrane. DO NOT BEND OR TWIST THE TRIM...

When you get the roof repaired, staple it back in place, then clean the trim of all the old sealant/putty, clean the sidewall of the trailer, apply a new layer of butyl (not clay putty) to the back of the trim and reinstall it. Use new screws if needed, don't reuse the rusted ones so that next time you'll know by the rust where there's a problem. If you reuse the old rusted screws, you can't identify "new problems" as easily.

Any RV dealership will have butyl putty tape. I use 1/8" thick by 3/4" wide. It comes in 30' rolls and costs about $5 per roll. Clay putty tape is cheaper, but dries out faster and when it dries, it cracks, leading to more water intrusion problems.

I'm sure you're reading this thinking, "WHAT IN THE HELL AM I FACING?"....

It seems daunting at this point in time, but if you pay attention to the way things come apart, and realize that they go back together the same way, don't force or pull anything out of shape and take your time cleaning the parts before reinstalling them, using new screws and fresh butyl putty tape and new vinyl insert, it's not a difficult job.... Admittedly, it's a time consuming job, but not difficult or technically challenging....

09-04-2021, 01:42 PM
Unlike John, I prefer the putty tape, it doesn’t get all “stretchy” and it’s hard to clean off what squishes out. Either one is ok IMO but you do need to use something. And I would use non self leveling Dicor on the top seam of the rail.

09-04-2021, 02:26 PM
Unlike Chuck (who disagrees with me) I agree with Chuck. :lol: Use non-self leveling DICOR along the top of the gutter trim rail. I believe it's labeled as "Non-Sag" rather than "non-self leveling". Anyway, use DICOR along the trim .....

09-04-2021, 04:10 PM
And there you have it!! I agree, that I disagree...but agree with John and Chuck! I use butyl as well but it is/can be squishy and definitely hard to "trim" off....but it seals....and sticks.

Takeaways for OP; whoever did the previous repairs had problems that weren't addressed due to the damage - now you got them. The task at hand is not hard or daunting, just time consuming - DON'T bend up that rail as I would have done when I was young....then regret it immediately.

The issue is what you're going to find under that roof covering; whether the decking was degraded a bit and the screws have worked themselves out due to that or if it is just rotted which will be a whole nother conversation. I'm looking to the bright side and if nothing else reposition the screws to get a better bite and seal the old holes - don't forget adhesive to put back under that roof material.

09-05-2021, 08:03 AM
Bear with me a little as I think this through. It "feels" as if the protrusions might be staples. It also "feels" like the rounded edge of the roof is a piece of sheet metal. It flexes just a little and is springy like a formed curve would be.

The side gutter which hides the staples holding down the roofing material is comprised of two pieces each about 16 feet long. The "strapping" that runs across the rear is about 9 feet long. I'm really, really hesitant to remove either the side or the back. And they would have to be removed to avoid any bending or crinkling of the lightweight metal.

If I'm correct about the staples, in my mind it's just another case of staples backing out because they were too short to bite effectively. If I make a 1 inch incision, pull the staple and replace it with a stainless steel screw and then use Dicor to seal the wound, I think the fix would hold.

If I'm wrong and major surgery is necessary then I need to find a good RV tech with experience in mending roofing. At 74 spending hours and hours on a ladder are days of yore!

While I know this approach is not the one you've recommended, do you think it will work?

09-05-2021, 08:36 AM
It will work, jut hope for no future repairs as EternaBond is pretty much ETERNAL!!

Just squirting Dicor over the cut is like pouring Hydrogen Peroxide on a cut. It wont last vey long.

09-05-2021, 08:45 AM
In my opinion (without seeing your trailer and with both of us not knowing what's under the TPO membrane) it's a gamble whether the roof decking is damaged or if it's "just short staples".

In previous years, all trailers had "transition caps" to round the edges of the roof. Over time, some "cheaper trailer lines" eliminated them and just wrapped the roof membrane over the side and screwed a trim strip over it. Through the years, many "higher priced trailer brands" have followed suit.

So, the "transition cap" has become an optional item, used on some trailers, omitted on others....

Yours has it, mine doesn't.. Here's a diagram of the three "typical transition processes"... Yours is, I believe, the lower left version.

As you can see, the aluminum rounded transition sits over the roof decking and the fiberglass sidewall and the TPO membrane lays over it, rounding the corner to "soften the angle". There's no "structure" under the transition molding, just empty space. It may be held in place by staples, screws or just adhesive.

The "gamble" is whether the roof decking under the TPO and under the aluminum transition is rottted, delaminated or in good condition. That's the reason Chuck and I recommended pulling the side trim and verifying what's under it.

Repairing it by "cutting the membrane" is a common means for the DIY to fix the immediate problem. What that procedure doesn't do is provide a means to fix the root problem (if there is rotten or delaminated decking). If you "fix the appearance but not the problem, what happens next??? It could be that your "cut, secure and seal" will fix the issue if there's nothing but a loose staple. On the other hand, you could be setting yourself up for a major repair costing 10 times or even more, if the "gamble doesn't pay off"....

For those who "do it professionally" (probably a bad choice of what to call it) it's not only about fixing the immediate appearance and owner concern, but in preserving the reputation of the business by doing it correctly the first time so the customer doesn't come back in a year, screaming about how bad we fixed his trailer and expecting a "redo to fix it right" with no additional charge.....

So, as a DIY, the gamble is pretty much "up to you".... If it works, you're golden... If it doesn't..... :hide:

You're not the first owner to have to make those decisions... Here's another thread from a few years ago with the same problem.... https://www.keystoneforums.com/forums/showthread.php?t=29205

09-05-2021, 09:36 AM
I wouldn't cut the roof to pull those staples/screws. If you look at the roof repair made ???? you can see that the chances that water came in there are almost certain. If you've ever worked with decking, when it becomes compromised due to moisture things like you see with those fasteners happen because the wood is rotted. Maybe it's not but I would say the odds are that it is.

If you choose to cut the membrane to pull and replace the fasteners I suspect you're not going to be able to get another one in there that is going to hold so then it will be back to plan B - pull up the membrane. I guess you could slit all of them and just pull them and "try" to get something to hold...but what if you can't? Now you've got slits all down the membrane and each one is a ticking time bomb, especially if you plan on keeping the trailer a while.

I had something similar on my last trailer as the fasteners sort of wanted to "push up" into the EPDM causing a little bump. Not in a centralized area but literally down both sides of the roof, not too bad and not due to water damage as this appears to be. I did put patches of Eternabond on each and every one of them because I did not want to pull up the membrane for a cosmetic issue but I didn't want them to wear through the roofing and me not see it, so, Eternabond it was. That was about year 2 of ownership and when I got rid of it at the end of year 6 they looked just like they did when I put them on. Your issue will be what's going on under that membrane; maybe it's past damage that is just letting the fasteners come loose over time; maybe damage is ongoing OR it might be something that could be fixed easily now but could be a bear if you let it go. That would drive me crazy. Good luck on whatever you choose - I understand the reluctance to try to tear into the side of the trailer these days.