Creativepart: I know the sinking feeling in your gut when you find "pukas" anywhere in your RV and the roof is one of those times when you ask yourself: "What do I do now?"
However, IMO, your roof concerns are more typical than you know! And it's not worth losing sleep over!
I see you have a 2017 Winnebago. I have a 2004 Itasca "Horizon" 40AD and I lost my roof in a El Paso wind storm 3 years ago. Fortunately, my insurance company paid for a new $35,000 roof, but before I went that route I attempted to repair my roof by spraying a $9,000 Rhino Liner on top. And while I thought that was a "home run" the shop let too many guys work on top my roof and they crushed one corner. ...So when I put out my slide it ripped the interior ceiling vinyl! Ug!!!
After that I took my RV to Winnebago in Forest City to get a new roof put on, but my decision to go this route had more to do with replacing the interior vinyl than it did with the integrity of the roof. And yes, there were roof bubbles (pukas) in several places in addition to craze marks that looked pretty deep, but I never had any water leaks!
To say the least, I put a lot of time in to understanding how Winnebago builds their roof; and they have not changed their roof design in over 20+ years!
The Winnebago foam roof is light weight (and probably cheaper to build) so that allowed Winnebago to put a few more creature comforts inside the coach vs. their competitors. However, I definitely think the foam roof is a weak point when it comes to structural integrity.
Roof bubbles occur because the Filon-Fiberglass roof (skin) separates from the luan it is glued to. And it's likely this occurs when you level your coach on uneven surfaces... and torque that big, rectangular box, which put's a lot of strain on that "Red Glue" which bonds the luan to the styrofoam and the fiberglass skin, which results in roof cosmetic issue like the puka(s) you found.
This is why your leveling jacks only provide minimal correction. So if you like to place blocks under your leveling jacks, you need to me mindful of what you are doing to your big, rectangular box!
(I like to level side to side before I level front to back.)
Winnebago roofs also make some "creaking noise" when they expand int he heat and/or contract in the cold. Have you noticed that?
No water damage will result from roof bubbles; and that filon-fiberglass stuff is extremely durable, which is why they say fiberglass roofs are "better" than rubber or EPDM roofs!
The real weak spot of a fiberglass roof is where the roof radius meets your side-channel.
Specifically, wind can enter just behind the driver's side roof cap, and get under the roof radius, and rip the fiberglass off. So the most critical inspection point on your roof is right in this area.
Some people have elected to Eternabond tape, and I would agree this is perhaps the best way to prevent a 5+ year old roof from wind damage; and it's the best way to never worry about your roof radius glue-maintenance again. However, there are some cosmetic trade-offs to this approach.
The problem is that all these roof channel sealants breakdown in the sun. And the industry has tried all of the different brands to see what works best and none of them last forever.
Right now I think the ProFlexRV or GeoCel clear is the roof-seam-sealant of choice right now:
So it's more important to worry about your roof radius seams, where the fiberglass is glued into the roof channel strip, than it is to worry about any roof bubbles or fiberglass separation
The problem is this: Silicon sealants offer the best UV protection, but lack adhesion strength. And polyurethane glues and other construction adhesives offer the best adhesion strength, but can breakdown in the sun in just 1 year!
My new roof is only 3 years old and I can already see where the seam sealant Winnebago used is breaking down. So I hope to address this concern soon, and before I have another wind problem.
Here are some roof maintenance tips:
* When you cut away or peal off your old glue... try not to break the seal of the old glue that is still sealing the fiberglass to the roof rail. ...Just cut away the f visible glue that is exposed to the sun. However, if the glue just lifts out of the channel then you should remove as much as you can.
* Use mineral spirits to clean the old glue off and to make sure you have a clean surface when you re-glue the roof channel.
* You will use tank 2 tubes of glue on the driver's side and 1 tube on the passenger side due to the fact you cannot re-glue under your awning. ...And I recommend you lay down some blue-tape you can pull up after you glue to achieve a very clean look.
* Without a doubt the biggest problem is working on a short ladder. And it's dangerous to try! So be sure you have a very tall construction ladder or scaffold setup. And I do not recommend you lay on top of your roof to re-glue this area, but you can if that is your only option.
* Do not put glue into the water channel. This is used to catch roof water runoff and to move water away from the coach sides.
* If you go with Eternabond tape, you will find the 2" tape is really too wide and they do not sell a 1" tape, but you can use the 2" tape if you like. Remember, the fiberglass will not leak water into your roof, so applying the tape really has only two purposes, and that is to prevent water from leaking in between your fiberglass roof liner and the roof channel, and to prevent the wind from ripping your roof off.
* Eternabond "black" was not too bad looking on top of my dark green roof radius; and while the color black may not be my first choice, it really was my only choice. Some people have said they have successfully cut the Eternabond tape in to 1" strips, but I'm not sure how they did this "cleanly." ...I think if you have a band saw and a guide that might work, but this stuff is really sticky. Eternabond tape also provides the best adhesion and is practically UV proof. However, I have never read any feed back from owners 5-10 years after they used Eternabond Tape so maybe someone will have more to say about that?
* Your roof corners are the weak spots. This is where wind first enters before it rips your roof off, so pay particular attention to these.
As a final note: Your insurance may or may not pay for roof wind damage if you cannot prove you have performed annual roof maintenance. So it is very important you keep a Maintenance Log and every year "log" that you performed a roof inspection and resealed all appropriate locations according to Winnebago specifications.
Eternabond also makes an aluminum tape you can paint. So in my mind, Winnebago should have use this stuff in place of gluing the radius seam to the roof channel and then they could have just painted it. And hear again a 1" strip would get the job done vs. a 2" tape strip that is overkill in my opinion.
I also think I will put this roof maintenance project on my to-do list when I visit Rocky Point again. And I will ask Carlos & Pablo to perform this job rather than do it myself. These guys are fantastic and really took care of some cargo door damage and other paint work this summer! Here's the link to that project if you care to take a look:
Aluminum Eternabond Tape: