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Author Topic: Fiberglass roof care  (Read 742 times)


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Fiberglass roof care
« on: April 22, 2017, 01:20:27 PM »
Could anyone suggest if further care is advisable on my 17 year old fiberglass roof which is mostly exposed to the sun.  I clean it and appears in pretty good shape.  Found couple of 3" hairline cracks near the shower skylight.  No leaks to date.  Would coating it with something like "Cool seal" be prudent, advisable, smart or dumb????   Other suggestions???
Winnebago 2000 Ultimate Freedom JD40 Cummins 350, 2013 Minnie Cooper Roadster

Gary RV_Wizard

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Re: Fiberglass roof care
« Reply #1 on: April 22, 2017, 07:14:20 PM »
Shouldn't need coating unless there is physical damage. If in doubt about those cracks, put a bit of lap sealant or Eternabond tape over them.

Nothing wrong with painting it or putting some sort of sealer over it if you want, though.

Dicor makes a good Fiberglass Roof Paint (I've used it myself).  It's more for beauty than leaks, though.
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Mile High

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Re: Fiberglass roof care
« Reply #2 on: April 24, 2017, 01:39:32 PM »
I would just give it a good rub out and wax using fiberglass products by McGuiars.

Critical part of Winnebago roof maintenance is the side edge seal (don't use lap sealant).  As shown in the diagram, the edge of the roof is held in it's channel with sealant.   If it separates and pops up, wind will finish the job and tear up that roof.  Most roof failures discussed are in cross winds on the highway.  Not sure if it happens from a little pressurization under the fiberglass, or just general distortion in the wind, but once it starts it goes instantly.

You can check the sealant by using your thumb and pushing in on the fiberglass at the at the rain gutter track.  If the sealant separates, it's shot and needs stripped out and replaced.  Sometimes, like on mine, the clear sealant over the dark paint is worse than the light paint.  If you are non-painted, you may only see differences on the side you park in the sun the most.  The overall idea is keep that sealant in good shape using Winnebagos sealant by part number.  It is similar to a quality silicone - clear for painted models.

Brad and Dory
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Harry B

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Re: Fiberglass roof care
« Reply #3 on: April 24, 2017, 03:27:24 PM »
All good points mentioned in the previous post.
Again DO NOT use a silicone product on that roof seam. You will regret that as nothing will stick to it next time it needs to be redone.
Winnebago uses a Thermolastic product on that seam. So good advice in the previous post about using the product recommended by Winnebago.
Harry - (Central FL)

2005 Horizon-KD
2013 Honda CR-V


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Re: Fiberglass roof care
« Reply #4 on: April 24, 2017, 06:57:23 PM »
what about using Mob-n-Glow or Zep concrete floor polish ?    I've hear of other people using this.

John Canfield

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Re: Fiberglass roof care
« Reply #5 on: April 25, 2017, 06:45:25 AM »
what about using Mob-n-Glow or Zep concrete floor polish ?    I've hear of other people using this.
That's a new one on me.
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