Replacing roof membrane. Pros & Cons of using TPO vs EPDM?

[Ozdiver]

I am in the unenviable position of having to replace the roof membrane on my 2016 Sundance 3600QB. Not due to leakage or damage, but from the adhesive giving up and in some areas being absent) from some areas. Technicians have advised that peeling back the EPDM and trying to reglue it will likely stretch or damage the membrane and make it not fit when it lays back down.
I am now trying to decide if puting another EPDM membrane on is the right path or whether a 60 mil TPO would be better/worse.

Have not found much empirical information online so far. Some very emotional opinions that I have trouble sorting out fact from fiction.
So I guess this is a devisive issue.

What is your experience with these products?
I understand
- EPDM has the longer history of use.
- The thinner TPO (45mil) can be a little stretchy.
- Both are used in flat roofing undustry.
- TPO requires heat welding on seams (if any). So installer needs equipment/skillset

Is one more resistant to damage?
Is one more UV stable than the other?
Does one require more maintenance than the other?

If I am going to spend this amount of money out of pocket, I only want to do it once.



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[danemayer]

Instead of replacing the roof, have you considered making a couple of very small openings to inject adhesive where needed? You can then cover the injection hole with a small disc of Eternabond, or even just caulk it.

 

[Ozdiver]

Instead of replacing the roof, have you considered making a couple of very small openings to inject adhesive where needed? You can then cover the injection hole with a small disc of Eternabond, or even just caulk it.

I had thought about it. The impression I got from my readings was that you avoid introducing any hole in the membrane at all cost. Obviously the adhesive used to lay these roofs is a rolled on and let tack off before laying the membrane on top. What would you suggest as an adhesive when doing this arthroscopic surgery on the roof?

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[danemayer]

I had thought about it. The impression I got from my readings was that you avoid introducing any hole in the membrane at all cost. Obviously the adhesive used to lay these roofs is a rolled on and let tack off before laying the membrane on top. What would you suggest as an adhesive when doing this arthroscopic surgery on the roof?

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I'd suggest calling Dicor 800.837.2059 to ask if they have a recommendation. They have an adhesive product, but you'd have to ask them if it would be effective in your situation.

If they don't have a recommendation, maybe they can advise on what type of adhesive to avoid. For example, they usually warn against anything that consists of petroleum distillates at it will damage the EPDM material.

Replacing the entire roof is extremely invasive and creates much greater opportunity for mishaps than making a couple of small holes.

Let us know what you find out.

 

[Ozdiver]

Well, not a bunch of useful info from Dicor. They are more about replacing the roof. So if I accept I would have to replace the membrane anyway, I can try something of my own design first without harm.
I decided to us a wet lay EPDM glue (low VOC) that is essentially a latex based glue hat you put on the substrate and lay the membrane down before it skins over.
I slit the membrane with a rasor blade in a 'Y' over the main area lacking adhesion.
Folded back the membrane (totally devoid of glue) and wiped as far as I could reach with denatured alcohol.
I applied some double sided eternabond tape on the roof under the slit. locations.
Spread the glue on the substrate as far under the membrane as I could reach.
Peeled the 2nd side of the eternabond and folded the membrane back in place.
Rolled joint.
Then layed 4" single sided eternabond tape over the cut locations.
Rolled again.

Now to see if it stays put once ihit the road......

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[danemayer]

Well, not a bunch of useful info from Dicor. They are more about replacing the roof. So if I accept I would have to replace the membrane anyway, I can try something of my own design first without harm.
I decided to us a wet lay EPDM glue (low VOC) that is essentially a latex based glue hat you put on the substrate and lay the membrane down before it skins over.
I slit the membrane with a rasor blade in a 'Y' over the main area lacking adhesion.
Folded back the membrane (totally devoid of glue) and wiped as far as I could reach with denatured alcohol.
I applied some double sided eternabond tape on the roof under the slit. locations.
Spread the glue on the substrate as far under the membrane as I could reach.
Peeled the 2nd side of the eternabond and folded the membrane back in place.
Rolled joint.
Then layed 4" single sided eternabond tape over the cut locations.
Rolled again.

Now to see if it stays put once ihit the road......

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It sounds like you just saved yourself thousands of dollars.

 

[Chrisandsama]

Ya the eternabond if properly applied will Outlast the membrane

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[Daley07]

If you are confused about choosing a coating for your RV, I would recommend looking at a TPO vs EPDM RV roof. In terms of cost, EPDM will be more economical than TPO. Speaking of durability, EPDM's rubber compound is well known; it's UV resistant and known to stand up to cold weather conditions. As for TPO, its seam strength can outperform both tapes and adhesives in EPDM settings. In terms of maintenance, a properly installed EPDM roof won't require much in the first place; you just need to apply the adhesive occasionally. But since the TPO membrane is not as easy to maintain as the EPDM membrane, it is necessary to use an activator to seal the repair.

 

[wdk450]

Daley (and other helpful responders):

It's a good idea to look at the last post DATES before posting a reply. The previous post was in 2018, 3 years ago.