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Topic: roof cracks (Read 1079 times) previous topic - next topic

roof cracks

One year revival of old issue. A year ago I had some roof cracks repaired and my roof painted with two coats of epoxy to stop white streaking and provide a nonskid surface, all by a very reliable truck and auto body shop, locally. Now the service manager at TN RV tells me I have several new, more serious, cracks. Some of these are through the fiberglass. I have also noted a leak from an unknown source  onto the sill of the window on the passenger side of the living room with no wet around the window. In addition the exterior sidewall of my shower has bowed inward.
Why am I getting roof cracks? Are these the cause of the leak and the shower wall separation?
I do not think there is a problem from the previous repairs.
Any suggestions, other than a call to Cory Rucker at FOT?
No RV! Have hung up the keys.
In the past: 2016 Winnebago Era, 1994 Foretravel U240, 1995 Foretravel U240 (wide body), 1999 Foretravel 320, 36 Foot, 2003 Foretravel U320 38 foot,

Re: roof cracks

Reply #1 –
For me, I would contact Xtreme, talk with Rance and James.  I am sure they have a better track record than a truck shop for fiberglass roofs.
Good luck

Re: roof cracks

Reply #2 –
Surface cracks are common with fiberglass but through cracks are relatively rare. Through cracks are caused either by lateral substrate movement stretching the fiberglass beyond its limits of expansion, horizontal substrate movement creating a shear point or repeated flexure of the fiberglass. You did not mention the location or nature of the cracks but unless they follow a straight line across the roof, my guess is you will find that some or much of the roof has delaminated from the plywood substrate, therefore the cause of the cracks would be flexure. Once delamination has occurred, when the coach is in motion the glass microscopically bends until it breaks just like you would bend wire until it breaks.

Someone needs to get up on the roof and sound it out by tapping the roof surface and listening for a hollow sound. With a little experience, one can just about outline the delaminated fiberglass area by listening to the sound it makes. I use a hard plastic hammer. Any delaminated areas will need to be cut out and reglassed. Leaving delamination on the roof will result in more and more area of delamination and more cracking. I highly recommend Xtreme in Nacogdoches for these repairs but any shop that does fiberglass work on RV's should be OK. Remember, fiberglass boats and cars do not typically have a substrate so an auto body shop may not be your best choice for large scale fiberglass repairs on an RV.

Delmination happens, I just had some fiberglass cut out and reglassed this spring at Xtreme. It can be caused by any number of reasons but is seldom a design flaw. It is usually caused by overstressing the chassis or poor initial preparation of the substrate such as contaminated or wet plywood.

I trust the foregoing helps everyone have a better understanding why fiberglass RV roofs crack. The nice thing about fiberglass is that it is relatively easy to permanently fix. 
The selected media item is not currently available.Kent Speers
Locust Grove, OK
1993 U300 SSE 40' (Restored at FOT 2009) Build 4323
720 watts Solar
6V92TA DDEC Silver Engine
2014 Subaru Outback

Re: roof cracks

Reply #3 –
Quote from: Kent Speers –
Surface cracks are common with fiberglass but through cracks are relatively rare. Through cracks are caused either by substrate movement stretching the fiberglass beyond its limits of expansion or repeated flexure of the fiberglass. You did not mention the location or nature of the cracks but unless they follow a straight line across the roof, my guess is you will find that some or much of the roof has delaminated from the plywood substrate, therefore the cause of the cracks would be flexure. Once delamination has occurred, when the coach is in motion the glass microscopically bends until it breaks just like you would bend wire until it breaks.

Someone needs to get up on the roof and sound it out by tapping the roof surface and listening for a hollow sound. With a little experience, one can just about outline the delaminated fiberglass area by listening to the sound it makes. I use a hard plastic hammer. Any delaminated areas will need to be cut out and reglassed. Leaving delamination on the roof will result in more and more area of delamination and more cracking. I highly recommend Xtreme in Nacogdoches for these repairs but any shop that does fiberglass work on RV's should be OK. Remember, fiberglass boats and cars do not typically have a substrate so an auto body shop may not be your best choice for large scale fiberglass repairs on an RV.

Delmination happens, I just had some fiberglass cut out and reglassed this spring at Xtreme. It can be caused by any number of reasons but is seldom a design flaw. It is usually caused by overstressing the chassis or poor initial preparation of the substrate such as contaminated or wet plywood.

I trust the foregoing helps everyone have a better understanding why fiberglass RV roofs crack. The nice thing about fiberglass is that it is relatively easy to permanently fix. 

Kent, Dave. I appreciate the replies, thank you. I am well aware of James Stallings expertise and have discussed this problem with him last year. The reason that I am going to FOT, I guess, is that I am hoping for some relief from Foretravel on the cost! I, too, feel that I have more than just a cracked roof. The cracks are generally diagonal but some are transverse, mostly short, some radiating from fixtures on the roof. Nearly all are between the batwing and the skylight in fore and aft orientation and from crest to crest laterally. They have been temporarily filled with a flexing filler.
No RV! Have hung up the keys.
In the past: 2016 Winnebago Era, 1994 Foretravel U240, 1995 Foretravel U240 (wide body), 1999 Foretravel 320, 36 Foot, 2003 Foretravel U320 38 foot,

Re: roof cracks

Reply #4 –
I too found a through crack in the roof of my 91 U225, between the front roof A/C and some sort of access panel over the dinette area, with some delamination. Going to repair this myself with a little help after we pull the AC unit out. One of my friends has done a fair bit of marine fiberglass work; with a little research, the right prep,  materials, and hard work, I reckon we'll fix it properly.

Spoke to Mike Grimes at FT parts yesterday afternoon and mentioned the crack. He told me FT recommends the roof be replaced when cracking appears, at the cost of $10K and up. Mmmmm.... no thanks.  :)

Steve
1991 U225 Grand Villa

Re: roof cracks

Reply #5 –
 at the cost of $10K and up

Oouch! Maybe I will be talking to James Stallings after all.
No RV! Have hung up the keys.
In the past: 2016 Winnebago Era, 1994 Foretravel U240, 1995 Foretravel U240 (wide body), 1999 Foretravel 320, 36 Foot, 2003 Foretravel U320 38 foot,

Re: roof cracks

Reply #6 –
Horace,

I had a roof delamination and crack repaired (on my 1995 U320CSE) by Gary Hawthorne in Nacgodoches, TX, his number is 936-564-2640. He is a former Foretravel employee and now has his own business.  He also replaced some decals on our coach that I bought from Encore.  I am pleased with his work and would go back for more repairs in the future when necessary. 

John
John Duld
1995 U320C SE 40'