Need info on using EPDM roof repair products

Thurman · 02-11-2014, 05:34 PM

So I found two (2) leaks on the top of my camper: 1) The rubbery type stuff at the base of the TV antennae had a crack along the backside of the rubbery sealant. There was also a leak where the TV co-ax cable entered the roof near the TV, the same type material failure.

I may not really like the guys at the only local RV place but sometimes I catch them in a good mood. They recommended removing all of the old sealing material as I could and they told me that it would not be easy. They were correct. This stuff does not set hard as silicone but is hard to remove. Until--I got an idea that maybe heating this stuff would help and it did. Warming this sealant make it easier to remove with just a putty knife being careful not to cut into the rubber EPDM roof material. After removing the base plate of the TV antennae and the plate the co-ax was mounted to I cleaned off all the old sealant I could remove from the actual EPDM roofing material.

According to their advise: First I cleaned the old area that had been covered with sealant and/or the TV antennae mounting plate with a smooth 3M scratch pad and Acetone. Before putting the mounting plates back on I used some sealant made by Dicor that is "self-leveling" then set the mounting plates into place. After securing the plates with screws I used some "Eternabond" tape to make a seal all around the edges of each mounting plate making sure to push this tape into place. The weather was in the low 70's and it seemed to work into place rather well. On top of this Eternabond tape I used the Dicor Lap Sealant for EPDM roofs (this stuff's expensive). As instructed I set a bead along the outermost edge of the Eternabond then worked inward with more beads of the Lap Sealant. I will say that they way this sealant starts to self-level and spread out is quite amazing. When completed this made a very nice looking very large sealed area.

The problem was the next morning (Tue.) when I went out to see what this area looked like after sitting overnight. The overnight temps here were in the mid-50's and today's high (Tue.) is expected to be in the low 50's. On Tuesday morning this sealant looked like just a bunch of bubbles. I pushed on a few with my fingers and each one of these were the same--felt as if they were full of air. Now I've got to wait until another pretty day, remove the sealant I just put on and do the sealant part all over again.

I can't help wonder if the weather/temps had anything to do with this or if the sealant being put over the Eternabond tape had some type of reaction. I made a call today to the local RV place and talked to the very person who recommended doing it this way. He stated that this is how he seals all roof protrusions whether on a new roof install or a repair job. He insists he uses the sealant first before installing anything that just sits on top of the roof, then the Eternabond, then more sealant. He claims that he has never had one just bubble up as this one has done. He may even call later today to come by and look at this, that would be darn nice of him.

Has anyone else had this Dicor 'self leveling' EPDM sealant bubble up on them after use? Would any of you think that using this sealant over the Eternabond would cause this? I'm not really wanting to remove all of this new sealant but certainly would to assure no more leaks. Thanks, David

TURBS · 02-11-2014, 05:43 PM

I think you may have used to much acetone. "Bubbles"

I used the same method to install my bedroom fan.

TURBS

Goshen is my playground.
The last man standing also has a sharpie

TURBS · 02-11-2014, 05:45 PM

I think the bubbles are from gasses from the acetone.

Unfortunately I'd say start over.

TURBS

Goshen is my playground.
The last man standing also has a sharpie

Thurman · 02-11-2014, 06:15 PM

One thing for sure, mine and your photos sure show the same symptoms. I will never say the Acetone had nothing to do with the bubbles, but I sure don't want to believe this. I have used Acetone in auto refinishing to clean off road scum, paint that somehow got onto a new car, and other things without any problems. After talking to my lady friend, who was here the entire roof-work time, she reminded me that there was at least an hour and a half between cleaning the EPDM with Acetone and the first application of sealer. I did not notice any bubbles in the EPDM roofing, where I cleaned the EPDM, before starting. Also remember that the first application of sealant went directly onto the EPDM roof before placing the TV antennae and co-ax into place. Of course if these bubbled I never would see them anyway. I'll just have to wait until another pretty day with some temps over 70 and try again. Danged, and I had bragged to my BFF on how good that job looked after I had finished and cleaned up all the mess.

TURBS · 02-11-2014, 10:05 PM

Quote:

Originally Posted by Thurman

One thing for sure, mine and your photos sure show the same symptoms. I will never say the Acetone had nothing to do with the bubbles, but I sure don't want to believe this. I have used Acetone in auto refinishing to clean off road scum, paint that somehow got onto a new car, and other things without any problems. After talking to my lady friend, who was here the entire roof-work time, she reminded me that there was at least an hour and a half between cleaning the EPDM with Acetone and the first application of sealer. I did not notice any bubbles in the EPDM roofing, where I cleaned the EPDM, before starting. Also remember that the first application of sealant went directly onto the EPDM roof before placing the TV antennae and co-ax into place. Of course if these bubbled I never would see them anyway. I'll just have to wait until another pretty day with some temps over 70 and try again. Danged, and I had bragged to my BFF on how good that job looked after I had finished and cleaned up all the mess.

What looks like bubbles are screw heads that i sealed up otherwise it's flat and smooth.

TURBS

Goshen is my playground.
The last man standing also has a sharpie

MillerTime · 02-11-2014, 11:32 PM

I think turbs nailed it.

Try using alcohol- the higher % stuff in the pharmacy section. Cleans good, isnt harsh, and evaporates quickly- so less chances of "solvent pops".
In the automotive collision industry, that's what we call it. Basically the base chemical, if it has not "flashed" (evaporated to a point where a top coat application will cover or adhere without traping uncured chemicals underneath) properly, solvent "pops" or sometimes blisters will occur. Its just the base solvent trying to escape the top coat. - happens frequently in paint applications when one is in a hurry.

lil2low · 02-12-2014, 01:35 AM

I used acetone once and the dicor wasn't adhering properly. I later found out that acetone leaves a residue on the roof that won't allow the lap sealant to adher. I was told from an rv dealer to use T.S.P. I didn't have any issues with the lap sealant from that point on.

BigJohnD · 02-12-2014, 07:51 AM

I've used mineral spirits before, but now just use the alcohol like MillerTime mentioned. Not really sure what the difference between the pharmacy alcohol and the "denatured" alcohol is. I think Dicor or somebody said use "denatured", and I've tried it but don't know why they say use that type.

Anybody know what "denatured" is?

I'd just start over to be on the safe side.

checca · 02-12-2014, 07:52 AM

As others have said acetone didn't evaporate before you applied the sealant. I use acetone or mineral spirits to clean, followed by alcohol to clean off any residue. Worked well for me so far.

Thurman · 02-12-2014, 12:57 PM

Interesting--I sent a note to Dicor about the problem I am having with the lap sealant bubbling up along with the photos. Someone from Dicor did reply and I appreciate the fact that they did. Here is the reply: You can use the sealant - just make sure you use just enough (1/4" to 3/8") to cover the edges. In colder weather and heavier applications, it will bubble the material. It will lay back flat when the sealant cures. So now I am wondering if the temperature changes we experienced between application (in the low '70's) during the afternoon and the drop we had (down to the mid '50's) overnight had something to do with the bubbling. We're expecting weather for Friday thru Sunday in the low '70's again so I will wait and look at these bubbles after it warms up this weekend. Even IF the bubbles lay back flat with warmer weather I don't want them. I'm too concerned that one or more bubbles will split/break and create a new leak. I'm sure I will remove the coating I just put on and re-do the entire thing later.

Thurman · 02-18-2014, 01:59 PM

Just an update on this problem: I contacted the "Eternabond" people and they were kind enough to get back with me. They wanted details as to how I cleaned this site before applying the Eternabon tape and photos of the affected site. I sent them to their rep and he responded with a phone call (not many company's do that anymore). Tom stated that this was a multi-problem situation with the following factors:
1) There had been moisture/water intrusion underneath the EPDM membrane just a week prior to my repair job and there "probably" was moisture still underneath the membrane. After I did the clean up at the antennae base, remounted the base, applied the Eternabond tape and the lap sealant I may have (I'd now say most likely did) create a "steam chamber" underneath the EPDM roofing material in that one area. Creating a steam underneath the membrane would make the EPDM get hot and bubble up.
2) Using "Simpe Green" was not the best thing I could have done., although recommended by the local RV shop. Simple Green contains certain chemicals that do not "flash off" readily. This residue may have attributed to the Eternabond tape not adhering as it should have. Tom recommended Acetone (which the RV place told me not to use as it is a petrol product) or de-natured alcohol to clean the EPDM material before applying anything.
3) Tom also mentioned that he thought the Winegarrd antennae bases, as I have, used a rubber type gasket to seal between the bottom of the antennae base and the roof. By using this type rubber gasket one would only have to mount the base, snug the screws down enough to hold the base, then use lap sealant only around the outer edge of the base. I actually did find a parts diagram on Winegarrd's website that showed a rubber gasket for the base, but-one would have to buy the base kit to get the gasket. I certainly like the idea of a gasket then the lap sealant around the edge only.
Being as we are to have beautiful weather for the next 4-5 days I am in the process of removing all that I messed up and starting over.

garbonz · 02-18-2014, 03:10 PM

denatured means something added to make the ethanol undrinkable (usually methanol). Isopropyl alcohol (rubbing alcohol) is already undrinkable and need no addition.

Either will work for this application.

Acetone evaporates REALLY quickly, faster than alcohol, but is so aggressive it may leach some of the EPDM additive compounds and cause the problem that way.

Best thing is eternabond cleaner and primer AFTER you are sure the surface and membrane is totally DRY.

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