1994 Gulfstream Ultra Roof Replacement

[xyourobob]

I have a thread on here from 2022 regarding my leaking roof. The RV came with problem and I never could completely stop the leaks. 4 years later it was replace the roof or ditch the RV. I decide to replace the roof and thought I would share it on here. I removed the vents, skylights and A/C. After removing the membrane I could see every sheet of Luan had water damage, so I removed it all. The ceiling above the cab also had to go. I now have all of the Luan for the roof and the ceiling over the cab cut to size and in place. I'm just waiting on a 7 day stretch with temps over 40 degrees. The recommended sealant Loctite PL300 suggests 7 days to cure, whew!

 

[RV_Lee122]

Big job! What membrane are you using?

 

[Larry N.]

Wow! Congrads.

 

[uchu]

A job not for the faint of heart...Congrats!

 

[Kirk]

I am impressed! I have dabbled in carpentry but you are braver than I would be. And it is looking really good. Any idea how many hours you have invested so far?

 

[xyourobob]

Big job! What membrane are you using?

RecPro RV PVC Rubber Roof Kit | 8.5' Wide | Camper, Motor Home, Trailer Roof | Made in USA (25 Feet)

 

[xyourobob]

I am impressed! I have dabbled in carpentry but you are braver than I would be. And it is looking really good. Any idea how many hours you have invested so far?

Funny you should ask, I added it up Sunday. Unfortunately I'm doing it alone and I've never done it before so I treaded lightly in the beginning of the tear off. You do get to understand how they build them though, it appears the entire roof/insulation/ceiling is assembled and glued while it's off the camper. Then screwed down to the main aluminum frame.

 

[xyourobob]

Finally the weather is on my side and I have a clear schedule so I am going to mount the membrane today but I have a couple of questions. Only someone that has had the roof off or jad been in manufacturing of these will know.
#1 the old plywood was mounted with 4 1/2" self tapping screws, I couldn't find 4 1/2 so I used 3 1/2" screws. All I could see was the top 1 1/2" aluminum roof frame mounting to another aluminum 1 1/2" frame under it, the plywood is 1/8". My questions is there another frame under the top two? I'd hate to put this membrane on and find that I didn't fully mount the roof.

#2 the sheet metal that makes up the front of the over the cab portion of the camper folds over on top of the membrane, another straight bracket lays on top and it all gets screwed to the roof and then covered with self leveling sealant, does this sound like the correct procedure? The old roof was a 2 ply and they had one ply under the bracket and the other over it.

 

[xyourobob]

 

[Gary RV_Wizard]

#1 the old plywood was mounted with 4 1/2" self tapping screws, I couldn't find 4 1/2 so I used 3 1/2" screws. All I could see was the top 1 1/2" aluminum roof frame mounting to another aluminum 1 1/2" frame under it, the plywood is 1/8". My questions is there another frame under the top two? I'd hate to put this membrane on and find that I didn't fully mount the roof.

A very real concern but it's doubtful anybody here will have enough knowledge of your 32 yo RV to answer the question.
Myself, I would get the same screws as the originals, just to be sure. RV manufacturers are cheapskates; they would not have used longer screws if a shorter, cheaper one would do.

I see #10, 4.5" self tapping, flat head screws advertised at Home Depot, Tractor Supply, and similar outlets. Might have to order them online, but they ought to be available next day or two. Fastener Superstore is another handy online source for this sort of hardware. Cheaper too.

If you need to get started, tack the new roof in place with the 3.5" and replace with the 4.5" when they arrive.

 

[Kirk]

Like Gary, I would not go with shorter screws. Way too much risk after all of the excellent work that you have done so far.

 

[udidwht]

I would also use some type of wood sealant (on all new wood) to seal and waterproof it prior to laying the membrane down.

 

[xyourobob]

Well I drilled a few holes with a very small drill bit in the closets where a 3rd layer of aluminum tubular frame would be located if it existed and I can confirm there is not a 3rd layer of the frame. Gulfstream was pissing away money on the 4 1/2" screws when they could have used 3 1/2" screws. I found this link online that talks about the cradle of strength which they refer to this tubular aluminum frame as, it shows two levels of aluminum tubing on the top. It's also interesting to note that the original first sheet of roofing Luanne did not have screws on the passenger side of the vehicle, almost like somebody forgot to do it in the factory.
I had already glued down the membrane before you posted the suggestion of sealing the wood before putting down the membrane. I did not see anybody else do that in the countless videos that I watched on doing this job, it sounds like a great idea, not sure if it would have any impact on the glue adhering. I'm now into putting the side rails over the membrane, I completed the rear so far.
I'm still not square on the membrane being secured over the cab, I know that the sheet metal comes down on top of the membrane, I'm wondering if it makes sense to bring the membrane after being glued on the wood, back up around the sheet metal and mount under the metal mounting bracket?

 

[xyourobob]

 

[xyourobob]

I also had this gap between the rear fiberglass wall and frame on the passenger side, it went from 3/4 of an inch on the passenger side down to flush with the frame on the driver side. This also must have happened in manufacturing, I cut a piece of insulation to put in there.