# Epdm problem / solution



## Onarooftop

New EPDM roof (Fully adhered to 1.5 ISO) 6 sq. Roof
Installation errors caused bubbles/blisters everywhere.
Likely errors - to much glue in some areas, and rolled in to soon.

Solution - Installing a new sheet of EPDM over existing after 
slicing/cutting out all bubbles. w.(Splice Adhesive)

Reasoning - If the current sheet is pulled up the face 
of the ISO will come off/ruined etc. 

Your thoughts on this?

Onarooftop

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## vtroofing

Speculation: Not your job and you feel the burden of the Owner's situation. At least it's 600 SF not 6,000 or 60,000 so why not start over? 

Temperature, or slightly damp ISO could cause it as well but you are probably right on the patience factor. 

Bubbles sometimes are just gas and flatten out, wrinkles not so much. Have you tried rolling it out? At least to a confined repairable area?

Does the roof drain in a drain in the center or over gutters? I would not be comfortable if it was the latter and the metal was under the sheet- however if it has good pitch and drainage to the center-ish then maybe. 

If it is not that adhered it may come up with minimal damage to ISO so replacing a few sheets here or there. Another option is laying another layer of 1/2" ISO over the top of the current ISO, or ISO and EPDM but then the metal situation comes into play. 

My supplier sells narrow 12" ect. widths of EPDM, for repairs such as wrinkles or bubbles, then cover tape all those edges. 

I've really leaned heavy on the Mechanically Fastened EPDM and High Wind the plates and have had zero call backs.


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## Grumpy

How long has the problem been present? 

I have had the situation you mentioned before but have found after a few cool nights it streches into place, then only a couple of bubbles may need to be patched in.

I agree with you and VT on the causes of the problem. 

If you do choose to lay over the existing, cut the existing to prevent a double vapor barrier. 

I used to promote fully adhered as a better system. Now after a few years of singleply installation experience, I am not so sure about that. Everything is situational. If it's a tear off with a nailable substrate I almost always now promote mechanically attached. Of course if it is a concrete or gypsum deck I promote fully adhered. Also if the roof will be used as a deck or garden I also promote fully adhered. Lay overs you could go either way, with mechanically attached or fully adhered. From a point of view of horizontal water migration, it may make more sense to install fully adhered on a lay over.


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## 1985gt

As grumpy said a good amount of bubbles will work them selfs out. As for the rest I would just patch them unless there is a outrageous amount. If that is the case. Remove all metal edges/ C/F 1/2 HD ISO and glue a new sheet. I would probably pull the old one off first. That is just personal preference. 

On a side note I do believe that you can just glue over and existing sheet with yellow glue. Don't quote me though check with the manufacture first.


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## tinner666

"On a side note I do believe that you can just glue over and existing sheet with yellow glue. Don't quote me though check with the manufacture first."

Another roofer told me that once. I was naive. I had to replace that 3'x4' patch later. It never adhered the sheets together. Good news is that it was my easiest tear-off ever!
I cut another patch and used seam tape around it and never had any issues with that. I believe that even so, I'd have been better off scrubbing, washing, priming, and using seam glue, and rolling in a new piece without any seam tape to prevent any voids.


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## Grumpy

Tinner, I did a 4 square patch about a year ago as instructed by the Firestone field rep. If I ever get a chance to go back and take a look, I'll let you know how it fares.


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## tinner666

What did he instruct you to do? Cut it out and patch it in?


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## 1985gt

tinner666 said:


> "On a side note I do believe that you can just glue over and existing sheet with yellow glue. Don't quote me though check with the manufacture first."
> 
> Another roofer told me that once. I was naive. I had to replace that 3'x4' patch later. It never adhered the sheets together. Good news is that it was my easiest tear-off ever!
> I cut another patch and used seam tape around it and never had any issues with that. I believe that even so, I'd have been better off scrubbing, washing, priming, and using seam glue, and rolling in a new piece without any seam tape to prevent any voids.


On a lay over is what I was referring too, not a 3' X 4' patch. I'm also not saying I have ever done one nor will we ever do one like that. 

By using seam adhesive in a lay over I would guess even a small 6 sq job would add up to more then throwing a cover board over it and laying a new sheet down.

Primer does roughly 200' of 3" seam. You have 6 sq we will call it a 20 X 30 roof.

Lets take the 20' width. 20 x 12= 240" 240/3=80 you would have 80 each of 3" strips. Now the length 30' so 80 x 30= 2400 LF you would need cleaner primer and splice/seam adhesive on.

2400 LF of cleaner = 12 Gal
2400 LF of Primer = 12 Gal X 2 since you have to do both sides.
2400 LF of Splice adhesive = 12 gal X 2. 


Now if my math is correct and using these numbers, I know for my cost in materials and labor to install that it would be cheaper to tear off the old EPDM, lay down a 1/2" Iso and new rubber. This is all of course if the roof is that bad.

Spreading the primer and splice adhesive would be a PITA if you ask my, you would have to use a roller, now we use 3" rollers for long seams with primer but I can't even think of using that on the field in the roof. They may make the primer and splice in 5 gal cans, we only use the 1 gal cans.


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## Grumpy

tinner666 said:


> What did he instruct you to do? Cut it out and patch it in?


 Me? No, just go right on top and fully adhere over the existing and then cover tape the seams if/as necessary. We used seam tape at the edges instead of cover tape. Worked out well as best as I can tell, but time will tell.


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