Roof Leak Mystery on a 'newer' (2018) Dynamax

[Cheese456]

2018 Dynamax. Last month I go out and the floor rug is soaked. I mean soaked! Water from recent rain was on floor and still dripping via the front Fantastic Fan. I have no way to get up there myself. Took it to the repair guy. He said Wow! You had a MAJOR hole in the seal around the Fantastic Fan. They repaired it. Next rainstorm, more leak. Same spot, but not as bad. Now they want to 're-seal' the whole roof. Question 1: Is it possible there was water in between the roof and the seal that slowly leaked in after the repair and there is no existing leak - is that even possible? 2) how unusual is it for a 2-year-old RV to have this (stored indoor and heated winter 2018-2019, and outdoor in AZ winter 2019-2020). Only 20,000 miles. Now they will re-seal it but with no guarantee against future leaks. Any thoughts/advice/comments welcome.

[johndjmix]

Get a moisture meter, or have someone with one check around to see whats wet, will help you find the leak!


--John

[MoJoe1003]

The roof does need to inspected every year and re-sealed as needed. It is part of the recommended maintenance on any RV. I had water leaks coming through both of my A/C units on our 2018 XL. Once the bolts were tightened up a bit the leaks were gone. I also had a major leak in the skylight over the shower which ultimately necessitated the replacement of the entire fiberglass roof covering and a couple of the plywood roof sheets. I believe the skylight leak was caused by a dealership technician stepping on and cracking the lip of the skylight while replacing my awning. He was working in the same area as the skylight and I had no leak prior to the awning work.
Before the roof was replaced, I had been on the roof on a number of occasions to check the seals and found several places where the sealant had dried out and cracked which would have eventually lead to water leaks if left unattended.
John is right, with that much water coming in, you should have a someone with a moisture meter check the ceiling to see if any wet spots remain. Once the plywood roof decking gets soaked and stays that way, there is, obviously, a chance for wood rot which leads to a rather expensive repair.

[Cheese456]

Wow. We've owned a few RVs and all this about annual inspections of the roof is new to me. Based on this, it seems likely I may indeed need a re-sealing and I shouldn't be surprised by that. And a test with a moisture meter. Not sure what that instrument looks like but I can google it and get on with it. Thanks so much for your helpful discussion.

[Grapehound]

Harbor Freight sells inexpensive moisture meters ($10 or so) for measuring moisture in wood/firewood. I assume one of these would help you identify wet spots. We had a leaky roof vent in our first RV, a Wildwood travel trailer, but none in the larger TT we had for 10 years or the fifth wheel we have had for 6 years. It is good to have an inspection done every year or two to make sure nothing is cracking or drying out. The sun can really play havoc with roof condition.

[halla]

We store ours inside a heated garage and I still check and re-seal the roof once a year. I go around the entire unit. I check the seal where the cab meets the coach, under the cabover, where the rear cap is sealed. It only takes an hour or so and it will hopefully save on some issues. The roof being all one piece, there are only a handful of places to check on top, and that is the easiest to seal in my opinion, it doesnt have to look as good as fiberglass areas with the paint.

[BKUHN]

What kind, or brand of sealer are people using ?
Thanks, Brian

[halla]

There is a thread on here from Brian Clemens. Dynamax Sealant Schematics. I am on my phone and it will not let me copy a link to that thread. If you cant find it, let me know and I will get on my PC. It lists all of the sealants the factory uses and in what location.

[Cheese456]

Thanks Brian. I have no idea what products they are using, or what the factory original product was. It's at a reputable and large RV service facility in Port Hadlock, WA. They called today and said they were going to try re-sealing the Fantastic fan behind the cab area where the water leaks in. It does look like whatever the original (factory) sealant was, it must have been a super thick paste by how it is smeared on there in big smears and chunks. I don't know if that is good or bad. Not sure if they will remove that an start over or what. But my $90K motorhome has a leak that has cost me hundreds so far, with no fix yet. And there is damage inside too from water. I had it in a heated garage in Grand Rapids Michgan winter '18-'19, and then ourdoors at an RV park winter '19-'20.

[milkman55]

Here is the link to the sealant thread

https://www.forestriverforums.com/fo...cs-216337.html

[ddobecki]

Couple things to note. Most items on the roof have multiple seals. The vent in question has butyl tape between the bottom of the lip of the vent and the roof. This putty like tape is the primary seal. The self leveling sealant that is poured over top is the secondary seal that is to protect the primary from the elements. If something leaks then the primary seal has failed for one reason or another. To properly repair that the vent should be removed, bother surfaces cleaned, the butyl reapplied, the vent reinstalled and finished with new self leveling.

You do not have to do this every time you perform maintenance. Touching up a bad spot in the self leveling is fine. But once there is a leak it should be done properly. Covering a void with self leveling that you know to be a leak should be considered a temporary repair to prevent damage until a proper repair can be made.

There is a couple possibilities. The vent was not the original source of the leak its just the area the water "chose" to exit the celling. The area was not properly prepped before new self leveling was applied so it did not bond and may still be leaking. If no roof maintenance has been performed in the three years since the motorhome was built it could be possible that there was more than one leak. Keep in mind a 2018 would likely have been built at some point in 2017.

I would recommend having the vent completely resealed. Should only take a competent tech a half hour. Also check over the rest of the roof. Check all the sealant for cracks, voids, peeling, etc.. These are areas that may be potential leaks. If you don't find anything and you have no more leaks then you should be fine. Just make sure to follow up with regular maintenance. If the leak persists then you may want to consider having the roof resealed (not just touched up).

Really long answer to your question but hopefully it help you and anyone else that may run into something similar.

[Cheese456]

Thank you very much for this great discussion. I will work with the RV shop to make sure all this is taken into account. And I have learned that roof maintenance is a critical part of RV maintenance.