Yet another DIY roof repair question thread...

[smithbill]

Just under a year ago, my wife and I started our Class A RV Adventure with the purchase of a 2003 35' National Dolphin. The rig has been a joy... and an endless destination of work and money (I know - RV's are like that - I [kinda] knew that getting in).

Here we are - I've put almost 10K on it already with plans to do many more. But last fall we encountered a significant water leak that has likely been there for some time. I was up on the roof this past weekend pulling all the sealant and molding off of the back end of the roof (the junction of the roof membrane and the fiberglass endcap) and because I'm a bit of a perfectionist - I'm thinking maybe I just need to redo the roof entirely.

I'm a pretty big DIY guy... have lots of tools, access to a place I can pull the roof off under cover at a friend's place who is also very handy and has even MORE tools than I do. I have watched a lot of YouTube videos (thank you AZ Expert) and today I called a number of different RV repair guys as well as product suppliers. From what I can tell - replacing the membrane with a new PVC one myself is the most cost effective (possibly about $2500 compared to $7K-$10K to pay a shop for any kind of new roof).

I was asked if I see black spots on the roof... the answer is 'no' - the roof actually looks fine. My basis for thinking the whole new membrane is that the existing membrane is obviously delaminated from the wood deck in places - most specifically on the radiused edges - but I'm thinking numerous other locations as well. Also - as I was scraping sealant on the edge - I noticed a bit of a 'star burst' of tiny cracks in one location on the radius - that indicated to me that the roof membrane is possibly getting brittle?

My questions today for this forum are:
1) there is common mention of 1/8" 'Luan'... I can't source that anywhere. I can find 1/8" plywood in birch (hardwood) which is likely laminated together with an interior style/quality glue - not sure that is good enough. I talked with one repair shop where he said he simply used 1/4" construction plywood for his decks. Does anyone know what is acceptable? I know I can purchase 5mm or .197" plywood all day at the big boxes...
2) Do I have to loosen and remove the fiberglass 'endcaps' (front and back) so I can overlay them back on the new deck/membrane? The front is just downright SCARY to me - what with the windshield in place and all. I've had repair guys tell me both yes and no (and AZ Expert... he removed them on the video I watched). That is the only real part of this job that 'scares' me.

I'm sure I'll have more questions - but if someone has already done this and wants to PM me with suggestions or discussion (or lives in South Texas and wants to help???) I'm all ready for the expertise here.

Thanks in advance!
Arden

[Ray Lenning]

You should have a fiberglass roof on a 2003 Dolphin not a rubber membrane ? it should't need replacing unless it has been busted or torn ? Recoating would be more inline for fiberglass . There are threads on here discussing options for recoating material . Dicore fiberglass coating , marine paint ect. Search the National section of the forum . There are several tube videos on recoating fiberglass roofs also.
Hope this helps.

[Thewellz]

I was thinking same as above...my 2000 tropical and my Tradewinds both had/have a filon roof. The outer radius edge of the filon is not supposed to be adhered to the substrate. I try not to lean or step on the edges to avoid any spider cracks. Dicor self leveling sealant works well on the end cap seams, but I used Eternabond over top of the factory sealant on both front and rear cap seams and its still good 10 years on.

[Dav L]

Post some pics of what you are looking at. Fundamental is to determine what material the roof is (fiberglass?). Are you seeing evidence of water penetration on the inside of the RV? Drips from ceiling? Stains down walls? Pull speaker / vents out in the ceiling and see if it's wet.
Fixing the leak is the easy part. Fixing the damage can be challenging.

Before fixing, ensure you have the RV in an overhead covered area that won't allow more water damage. I say before just in case you should be pulling the roof off to repair the water damage....lets get a full diagnosis in place before patching things up.

[smithbill]

I'll attach some pics to see if they make sense. Not having any experience with roofing membranes of any type (rubber/TPO/PVC/filon) - I just assumed it would be TPO or EDPM. Considering the coach is 18 years old, there is no 'black' showing through and it does look mostly real good - maybe it is filon/fiberglass?

I know there is internal water damage - during our vacation last fall, we hit a couple good rainstorms and the back wall of the coach, through to the floor was just soaked. There is a wallpapered crown molding at the top inside edge where the wallpaper has bubbled and the rear facing window was all wet and soft.

If I am over-reacting... then I'm going to be super happy to come back to just 'reacting'. If I can coat the roof and seal the seams - I don't mind peeling off all the existing dicor and reseating all the roof parts with new butyl tape and Dicor caulking.

Here are a couple pictures I took this past weekend when I was working on it. I have my fingers in there just to provide a size reference (I don't have big hands - I use a size M nitrile glove).

The first 2 are what the roof looked like when I got last June/July - I powerwashed it last fall (light duty electric washer from Harbor Freight). It's reasonably white all over now. There may be more of these small cracks elsewhere - I have not done a close inspection looking for them. Also - I'm pretty sure at least one solar panel mount is now leaking - we stay in it overnight at our friend's place where we store it and we had a light rain. The roof carpet right below the panels was wet. I know water can 'move' a long ways before appearing... but it goes to the thought that (depending on the verdict of the team here rubber or fiberglass) I'm going to reseal EVERYTHING up on the roof.

Thanks again everyone - your help and ideas are great!

Arden

[Thewellz]

Don't panic too much.. You definitely have a filon fiberglass roof.It needs a good scrubbing! I've owned 2 National RV's and they are well built solid Motorhome's. Those minor cracks can be covered with resin or roof tape, not a huge deal. Most likely the water damage will be limited to the luan board on the interior wall , unless you see obvious delamination on the outside fiberglass wall. I repaired both passenger and drivers side interior walls on my 2000 Tropi-cal due to leaky window and roof cap seals. I actually bought it knowing it had water damaged walls. I'd re-seal your end caps with dicor and then use a 4 inch strip of eternabond Overtop as a water diverter. Cut the walls back until you reach solid undamaged luan leaving the very last layer bonded to the wall studs, remove any affected windows, treat any mold and then dry everything out with a space heater. I found wallpapered luan at a local finnishing/ plywood store and it matched almost perfect with seam tape to match, otherwise you can find wallpaper to match up afterward. Cut the new luan to fit the area and PL it in place. I used a couple of metal tapping screws to hold it at the bottom edge and braced across to the far wall while the PL dried. Then cut out your window opening, reinstall the window with putty tape and seal it up with pro-flex rv sealant around the frame. If the carpeted ceiling is still intact and not hanging down and not soft when you press on it, I'd leave it alone there is likely 1/2" or 3/4 " plywood under the filon.These are the steps I've done with success, its not too difficult to do with patience and relatively cheap too.. hope this helps you a bit. Good luck with it.

[eddndee]

Seal the water entry points and dry it out. I learned the value of a quality electric dehumidifier recently and I am sorry I didn’t get one sooner.

[Ray Lenning]

Heres a video on recoating a fiberglass roof . Just happens to be on a Dolphin .

https://youtu.be/a_aEmUCa5Hw

[smithbill]

Another weekend of working on the roof... and of course - more questions.

I may have started this in the wrong sequence - but before I knew what I was dealing with, I started pulling the caulk off of rear 'end cap' where the most obvious leak was. After watching the Dicor professional video on sealing the fiberglass/filon (thank you Ray Lenning), I realized I may have caused myself more delays to the coating step. I have learned over 40 years of home ownership that spending a bit more up front and then following through with regular maintenance... life is really a lot easier. That was my plan for this roof rehab.

I think there are at least 3 different sealants used on different parts and components on the roof. The solar panel clips were definitely sealed with clear Silicone and then covered with Dicor. The grey tank roof vent had some kind of white caulking which did not have the same properties of silicone, but still removed as an intact 'rubbery' seal. And the satellite system appears to have 2 different sealants. The first one applied has similar texture to Dicor which appears to have been used on top of the first one. There was also a yellow (almost looked like wax?) sealant on an electronic box mounted on the roof. I have included a picture of that stuff - it's still very pliable and 'rubbery'. In that same picture in the upper right corner - the 2 different sealants (by color) are visible holding down the cables.

The solar panel clips were screwed down with the screw head covered with a blob of silicone sealant, then overlayed with Dicor. I cleaned the silicone off as much as I can with a scraper - mineral spirits didn't seem to dissolve or soften it. I turn to you experts... do I need to completely remove the remaining think layer of Silicone before I apply Dicor lap sealant?

I am including a picture of the clips - as you can see - they are loose and thus unlikely sealed. I am planning on pulling all the clips up, using a small piece of butyl tape underneath and then Dicor lap sealant all around. Is that too little? too much? not a good idea?

The next question... in the middle of the roof was this small solar panel that was edge sealed and held in place with Dicor. When I peeled the Dicor off - underneath there was a lot of dirt (likely from water penetration) and what looked like very soft tar - about the consistency of pudding in an 'all you can eat' food bar. The cable is fed directly into a hole in the roof and of course Dicor'd all around. Does anyone have any idea what that panel is supposed to be connected to on the other end? There is no cable protruding into the coach that I have ever noticed so I'm thinking that the cable somehow runs somewhere in the roof. Anyone know what that is about?

[EDIT of course... a little research here in the forums and I discover all I ever wanted to know about that little solar panel. feel free to ignore that question - I think I have my answers...]

And finally... in my attempt to rehab the roof - there is a skylight over the shower. But it's not just a smoked dome that is screwed to the roof from the top. It appears to be some kind of frame that 'sandwiches' the roof and the inside sealing and then the smoked dome is mounted into/onto the frame with a black seal of some kind. Again - 2 pictures are attached to assist in the identification. Depending on what it is and the cost of replacement - my plan is to do just that... replace it. If I'm spending money why stop now? Can anyone tell me what kind of skylight this is? It appears to be something National RV used - I see the same unit in the roof sealing video mentioned at the beginning of this loooooong tome I have created.

Thanks in advance for all the information - everyone is so very knowledgeable and helpful. I look forward to that day when I can 'pass it on' myself.

Arden

[Ray Lenning]

Try this link I found it in the national section on here . And yes you will learn a lot and be able to pass on info in short order .

https://www.google.com/url?sa=t&rct=...fVQm1fhHOrBdsY

[Thewellz]

To answer your question, I would recommend you remove as much of the old sealant/silicone as possible as dicor won't adhere to silicone and clean the area well with spirits or acetone. It is hard to remove it all where the radius attaches to the gutter, take the loose pieces off and then give it a good wipe down with acetone to remove any silicone, it will give you a good bonding surface, In my experience I've found Pro-flex sealant to be better than Dicore for the verticle applications, it can be bought in white and is easy to apply, and gives a cleaner finnished look.

[smithbill]

Time has passed... more work has been done on the roof... more questions surface...

I have pulled all the sealant off the roof and there is definitely a mix used. I pulled the end cap molding which appeared to be mostly Dicor and butyl tape and most of the other components were also sealed with Dicor.

The exceptions were the solar panel clips which were sealed with clear silicone. I have scraped off as much as I can - but you can't totally scrape off silicone. I tried acetone to clean them - but that just barely softened the caulk. There isn't a big patch of silicone - but there is certainly a film left on the roof where these clips were mounted. Any other chemical concoctions I can try to see if it will remove the silicone?

The rain gutter/awning holder is (I think) fairly standard aluminum screwed in every few inches. However the channel that the screws are in, appears to have been filled with a white caulking much more solid than Dicor self-leveling and it is very 'stretchy'. I tried to attach a video of me 'stretching' this material out - but no video uploads are allowed. I have attached a pic of the screw channel filled with the caulking and the cover hanging. The snap on cap which appears to have been put on before the caulking cured and is stabilized and gripped by the white caulk. The screw heads are rusty - so I know the caulk is compromised. Plus - it seems like there is just a tiny bead of this same white caulking at the top of the plastic snap-on cap and the coach - to prevent water getting down between the gutter and the coach. This material is dry, dirty and cracked and therefore no longer working.

Anyone have any idea what this material is? It doesn't have the same texture or consistency of 100% silicone - so it has to be something else with good holding power. I'm wondering if it is a lap sealant for vertical surfaces? or just a really good caulking compound like OSI Quad.

And finally - I reviewed the video on the Dicor fiberglass coating. Researching alternatives (just because I like options), it seems this one is always the top choice. What I don't like is the 2-weeks between resealing and then coating. Does anyone have any options they have tried that I can look into?

Thanks again for all the great help, direction and information.

Arden

[Ray Lenning]

Here is a national sealant call out .

[eddndee]

Try Re-mov for removing silicone residue. I have had good results with it. Re-Mov