Plywood Seams Showing under the fiberglass Roof

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FrontrangeRVer

FrontrangeRVer

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Dec 12, 2008
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After spending 3 days in 25 degree weather, washing all the salt and road scum off our chassis and motorhome from our recent ski trip.  I got on top of my unit to install the ADCO cover, and noticed some VERY disconcerning bulges (best word I could come up with) where the underlying plywood seams are showing underneath the fiberglas roof material.  There is no way that moisture has gotten between the ceiling and the roof.....only way this could have happened is the air conditioning duct work is in the ceiling and could have "bowed" the roof plywood somewhat.

Should I be concerned?   :eek:
 
Mark - you can notice the roof supports on my roof.  I for one am not real concerned - I think this is a natural process of the roof skin settling in, at least on my Horizon.
 
Yes John...I can see the aluminum roof supports.

I am talking about the plywood seams every four feet all along the length of the motorhome.
 
John, we have the same roof if you have the duct work for the basement air.  The roof sandwich includes (from the top down) a 1/16" fiberglass sheet - 1/8" luan - block styrofoam - 1/8" luan - and the ceiling covering of either a thin fabric of some type.

The 4x8 foot sheets of 1/8" luan are layed horizontally down the length of the roof....so for a say 40 foot length of roof, you will have approx. 10 sheets of luan under your fiberglass roof.

My rephrase of the question might be "Should I be concerned with seeing the luan underlayment seams every 4 feet underneath my fiberglass roof?"
 
FrontrangeRVer said:
My rephrase of the question might be "Should I be concerned with seeing the luan underlayment seams every 4 feet underneath my fiberglass roof?"
Click to expand...

Ah - we most likely do, then.  I don't remember noticing any seams on my roof - I cleaned the roof a couple of months ago.  I need to get on the roof for some work when we have some good weather and I'll be more observant.
 
I think John is right.  Just because you can see the seam doesn't mean that there is water intrusion, or even a problem.  I would not be concerned unless the fiberglass skin starts to show distress along the seams.  I had a rubber roof on my last 5ver, and I could see the roof seams from the first day.  The fiberglass is thicker, so it would take longer to imprint against the plywood.  As long as the fiberglass doesn't start to crack or flake, and the rest starts of the fiberglass looks like it is still adhered to the wood, I wouldn't worry about it.

Sarge
 
Thanks Sarge.

You can definately see the seams on mine....some are VERY pronounced!  The fiberglass is raised a (very) little along each seam.  I get up on the roof to cover it in the Winter and then the Spring.  The seams are more pronounced now....I dont know if it is the cold, and like I said, I am concerned about the pushing up the fiberglass along the seams.

I believe most people wouldn't notice this, as I don't think most will get on their roofs....
 
Yeah....I might do that in the Spring....when I uncover it....or if the weather is good for a couple of days....Im a bit nervous about it.
 
Max, I dont have any PM's from you here.  You trying to send me one?

I'll send you one here....see if you recieve it.
 
Mark - I was on my roof today (an ugly situation with my Datastorm, but that's another story) and carefully looked it over.  All I can notice are the roof 'ribs' that are athwarthships (I love using my marine terminology for RVs  ;D) - absolutely no other seams, ridges, joints, or anything else noticeable other than a ridge every few feet.

There is the dirt, however.....
 
The ridge every few feet john....Would you say that is every four feet?  Like luan underlayment under the fiberglass?  I have a ridge every four feet.

Thanks for checking
 
Oldies but goodies...

  My old unit (Adventurer 1995) has a perfectly solid roof, no sign of any abnormality anywhere. Guess they cut a few corners in production somewhere along the line over the years.

   I am smiling, the depreciation has dwindled to almost 0. Runs like new.

carson FL



   
 
FrontrangeRVer said:
The ridge every few feet john....Would you say that is every four feet?  Like luan underlayment under the fiberglass?  I have a ridge every four feet.

Thanks for checking
Click to expand...

Mark - pretty certain the ridges are the roof trusses and not a substrate.  Yeah - could have been every four feet.
 
Okay - I have been on my roof for most of the morning (  :mad: ).  I measured the ridges at exactly four feet apart.

[off-topic]
Projects of the day - figure out why the signal quality on my Datastorm is in the low 50s instead of the low 70s.  After fighting this on and off for a year, I replaced the dish itself and that was the silver bullet!  Second project - figure out why my King Dome doesn't have a signal on output #2.  King Dome in now on my workbench.  It has a problem in the rotating joint  :mad:
[/off-topic]
 
Four feet apart....that is the luan.  Glad to hear you have the same roof "problem".  lol

There are only maybe 3 or 4 aluminum "trusses"...if you want to call them that....
 
Shoot Mark, now you got me thinking.  I was just up there a few days ago to sweep off the debris before I closed the slides.  I didn't notice anything, but I wasn't really looking either. Especially since our rigs are the same year.  Nuts, now I gotta check.............
 
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