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Old 07-22-2012, 11:21 PM   #1
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Leaks in membrane roof at posts and edge


My daughter and son-in-law bought their first house in November. It has a garage with a flat membrane roof of some kind. It leaks where it attaches to the brick house wall and where each post on the decorative railing penetrates the membrane.

It appears to me to be some kind of rubber. I have been researching EPDM membrane roofing, because I assume that is what it is. It appears to me that the roofer took some shortcuts.

1. Where the membrane meets the brick wall, it appears to have been caulked only at the top. No transition bar was used, it was not mechanically attached to the brick, and no counterflashing was installed in the brick.

2. The vinyl posts on the decorative railing all leak. They were wrapped with some tape sealed to the membrane roof, but there are gaps between the vinyl and the tape that were not sealed. Also, some gaps in the tape at the roof were sealed, but the sealing has broken.

I have attached photos of the edge and a post.

I'm trying to help them to fix the leaks. They are serious enough to be causing dry rot in the wood below. I have no experience with membrane roofing. I've learned some online. I really expect that I need to install some transition bar on the membrane at the brick and seal it to the brick. I'd like suggestions for products that would be appropriate to seal the vinyl to the membrane at the posts, and to seal the membrane to the brick at the edges. I understand that only some products are compatible with membrane roofing.

Products and sources would be appreciated. The house is in Utah.
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Leaks in membrane roof at posts and edge-edge_img_7477.jpg   Leaks in membrane roof at posts and edge-post1_img_7482.jpg  

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Old 07-23-2012, 05:29 AM   #2
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Leaks in membrane roof at posts and edge


You can't seal it to the posts. Best bet is to remove the post and the roof too. Inside the posts are supposed to be 4x4 or 6x6 posta the are part of the framing. hopefully, you have that. If not, a rebuild is necessary. The posts must be bolted tot he rafters below the roof deck.
Then the roof goes on, and the posts are kerfed about 5" up. The roof gets done around the posts and they are counterflashed. THEN, the vinyl cladding is reinstalled, and shuld be above the roof an inch or two.

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Old 07-23-2012, 05:30 AM   #3
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Leaks in membrane roof at posts and edge


That screwed down bar is totally wrong too and has no place on the roof.

Last edited by tinner666; 07-23-2012 at 07:49 AM. Reason: typo
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Old 07-23-2012, 02:26 PM   #4
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Leaks in membrane roof at posts and edge


Did they get a home inspection, that should have been noted...its as obvious as hell there an issue with that installation.
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Old 07-24-2012, 12:45 PM   #5
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Leaks in membrane roof at posts and edge


They did get an inspection. It noted the edge problem with the membrane. However, they purchased the home as-is, so now we need to figure out how to fix it ourselves L.

The metal bars terminate the edge of the roof where it transitions onto a deck which is at a slightly lower level than the roof decking. I think that is why it was done that way.




I was surprised that you said that the vinyl couldn’t be sealed to the EPDM membrane.
  • Is there a chemical incompatibility between EPDM and vinyl?
  • Is there some other incompatibility, like expansion/contraction rates that would doom the joint?
  • Is there some other problem? It occurs to me that water might get inside of the vinyl cladding through the railing, along the spindles and rails, and then get into the garage even though the membrane is sealed to the outside of the vinyl cladding.
Here is how I was planning to try to fix the leaks based on my current knowledge. Given that these are not the best way to do the job, but we can’t afford to replace the roof right now, could you please evaluate these temporary fixes from your experience? I hope to have the fixes last as long as the main part of the roof, which is of unknown age.

1) Edge leak: Mechanically attach the membrane to the brick wall by drilling the brick and sandwiching the membrane between the brick and a metal bar (probably aluminum). Make a flashing to fit into the next mortar line above the membrane-to-brick joint long enough to overlap the joint to keep water off of the joint. Seal the flashing into the mortar line with urethane or MS (polyether) sealant.
2) Post leaks: If there are no sealants that will adhere to both EPDM and vinyl, then use a sealant that will adhere to vinyl. Form a “flashing” of sealant that adheres to the vinyl just above the membrane to vinyl joint and overlaps the joint to keep water off of the joint. I might first overlap the joint with tape, either aluminum or “gas pipe” tape, to form part of this flashing, and seal the top of the tape to the vinyl.
Do you feel that either 1 or 2 would be effective temporary fixes?

Can you suggest more effective temporary fixes?
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Old 07-24-2012, 04:39 PM   #6
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Leaks in membrane roof at posts and edge


1) Edge leak: Mechanically attach the membrane to the brick wall by drilling the brick and sandwiching the membrane between the brick and a metal bar (probably aluminum). Make a flashing to fit into the next mortar line above the membrane-to-brick joint long enough to overlap the joint to keep water off of the joint. Seal the flashing into the mortar line with urethane or MS (polyether) sealant.
Sounds like you're talking about counter-flashing. That should work.




"Is there a chemical incompatibility between EPDM and vinyl?
Is there some other incompatibility, like expansion/contraction rates that would doom the joint?
Is there some other problem? It occurs to me that water might get inside of the vinyl cladding through the railing, along the spindles and rails, and then get into the garage even though the membrane is sealed to the outside of the vinyl cladding. "

Probably all of your listed reasons. It's just wrong.

"2)Post leaks: If there are no sealants that will adhere to both EPDM and vinyl, then use a sealant that will adhere to vinyl. Form a “flashing” of sealant that adheres to the vinyl just above the membrane to vinyl joint and overlaps the joint to keep water off of the joint. I might first overlap the joint with tape, either aluminum or “gas pipe” tape, to form part of this flashing, and seal the top of the tape to the vinyl. "
Completley uncharted territory on my part. No clue whatsoever on temp fixes. Sorry, I just don't have an answer.

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Old 07-24-2012, 05:03 PM   #7
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Leaks in membrane roof at posts and edge


I agree with Tinner on the wall detail.

Could we get an over all pic of the deck ?
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Old 07-24-2012, 05:04 PM   #8
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Leaks in membrane roof at posts and edge


I'd cut into the vinyl post itself and fabricate a counter flashing before relying on tape.
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Old 07-24-2012, 08:36 PM   #9
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Leaks in membrane roof at posts and edge


Quote:
Originally Posted by kwikfishron View Post
I'd cut into the vinyl post itself and fabricate a counter flashing before relying on tape.
KFRon, something about this nagged me. Then I thought what it was. If they did this roof as wrong as I think, those vinyl posts probably don't have real posts inside them. Since they're hollow covers, cutting them could make tham just fall over.
You'd have to do some serious testing before trying that, I think.
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Old 07-24-2012, 08:39 PM   #10
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Leaks in membrane roof at posts and edge


BTW, is vinyl safe for a roof application as a safety rail? Anybody? I'm assuming a 10' drop as an average.
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Old 07-29-2012, 06:21 PM   #11
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Leaks in membrane roof at posts and edge


Sorry for the delayed response. As you might guess, the roof is not the only problem I am helping them with J. I’m also building storage cabinets, installing electrical wiring, working with sprinklers, exterminating bees…

The membrane roof is over the garage and is on the same approximate level as a large covered deck at the rear of the house. In the past, the garage roof was tar and gravel, and had a deck over that with wooden safety rail. At some point, the wooden rail was replaced with vinyl, and the tar and gravel was replaced with membrane. The garage roof is no longer accessible for foot traffic (deck railing isolates it, and there is no decking on the garage), although the railing is there for decorative purposes.
I walked the roof to learn more. I found this stamped on the membrane in several places: “10424A JJCBM 045 EPDM.” I assume that this confirms that the roof is EPDM rubber, 0.045” thick. I assume that the remainder of the characters give the mfgr name and date code. Any ideas what they are?

I finally found a post cap that I could wrestle off. Looking inside confirmed that no real trees were harmed in creating this part of the railing. The posts are hollow vinyl with no wood in them. At the very bottom of the post, I could see a 4 x 4” steel plate and the head of a lag bolt. In the garage under each post, I find a 4 x 4” wooden block nailed between the joists under each post. I believe that the lag bolts go into these 4 x 4s. This inspection confirms that any water that gets inside of the vinyl rails runs into the hollow vinyl posts and would then run into the garage, completely bypassing the roof.

Being ignorant of installation of vinyl fencing/railing, I looked for instructions. I found several sets of detailed installation instructions for vinyl fencing. None of them mentioned sealing the joints, or using wood in the posts. One explained when it as necessary to put rebar into the posts and how deep to fill them with concrete. I couldn’t find instructions for using vinyl as deck railing.

I plan to do a water test this week. I will spray only the membrane to post interface to see if there’s a leak there. If no leak shows up, then I will spray the railing as well, to see if water is getting into the vinyl and then into the garage. I’ll report on what I find.
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Old 07-29-2012, 06:39 PM   #12
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Leaks in membrane roof at posts and edge


Could you remove all the posts and install a treated 4x4, then have the EPDM tied into the 4x4's properly. Finally, slide the vinyl posts over the 4x4.

Your correcting the leak issue, the appearance of the membrane tie in to the posts, and having proper structure inside those vinyl deck posts. The only down side is the EPDM will have visible patching vs a pro who would have done it properly from the get go.
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Old 08-14-2012, 10:25 AM   #13
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Leaks in membrane roof at posts and edge


I owe an update on progress with the roof. I tarped off everything above the joint between one post and the EPDM and sprayed the joint pretty heavily with water for 5 minutes or so. A small amount of water – a few drips – appeared below in the garage. So the joint should be sealed. Then I sprayed water only on the vinyl railing between 2 posts, being careful that no water got on any membrane joints. Water flowed freely into the garage below. Removing the top cap on the vinyl post, we could see water flowing from the rail into the post and puddling there. So water carried into the post through holes in the rail for the spindles is the main cause of leaking and roof deck damage.

As it is expensive (and therefore impractical) to remove the roof and railing at this time, we looked for a solution that would inhibit further damage to the garage by plugging the leaks through the posts. Here’s what we are doing: Under the bottom railing at each hollow vinyl post, we are drilling a ¼ inch drain hole. We are then filling the bottom of each post up to the bottom of the drain hole with a pourable one-part polyether sealant which is designed for sealing pitch pans on EPDM roofs. The sealant seals the water out of the bottom of the post, and it runs out the drain hole instead. We’ve tried it on one post, and it works great. No water at all appeared in the garage, although the test water remained in the post all day.

Some details, for anyone who tries this at home: We used Carlisle “SureSeal One Part Pourable Sealer.” One part sealer is better than a 2-part sealer so you have time to work with it. The sealer is quite viscous. To deliver it to the bottom of the post without dribbling it all over, we put a ½ inch schedule 200 PVC pipe down the post past the rails. We calculated the volume of sealer required and poured that into a funnel and down the pipe. We cleared the pipe of sealant by running a dowel with rubber on the end down the pipe. This way we knew that the whole amount of sealant had been delivered to the post. 400 ml is the amount of sealer we found would fill the post up to the drain hole. The sealant comes in 2 liter pouches. The 13 posts will be filled and sealed off using somewhat less than 3 pouches, at a total cost in material of less than $150. We found this material locally, but an internet search turns up at least one discount supplier that will ship to those who can’t find it locally.

After the posts are filled, which is the major source of our leakage, we will seal the EPDM-to-vinyl joints with gunnable sealer. We still need to figure out how to seal the EPDM to the brick, since the EPDM has pulled away. The current plan is to screw transition bar through the EPDM to the brick and seal the joint.
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Old 09-09-2012, 07:22 PM   #14
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Here’s the final roof leak update. As described, we sealed the bottom of each hollow vinyl post with one-part pourable sealer and drilled a drain hole in each one to get the water out of the post . We applied 26 feet of transition bar along the joint between the brick and the EPDM and sealed the top of the transition bar to the brick and the sealed ttaching screws with polyether sealant. We sealed the minor leaks where the posts passed through the EPDM.

Some days later, a drenching rainstorm occurred that lasted all night. No leaks!!!

Thanks for your help and suggestions. With your help, I was able to understand the problem and build my confidence enough to fix this perplexing leak.

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