# 50' x 85' wood barrel roof advice



## resroofer

hi professionals

-we have a 50' x 85' wood barrel roof lots of slope on our shop

-it has about about 1" of existing what looks like coaltar and mop on 
which we dont want to remove

-leaning towards single 50' x 85' 45mil sheet of mechanically fastened epdm 

-95% of our roofing jobs are residential 

what do you guys recommend ?

should we put a separation sheet over existing cap sheets to keep new epdm from contamination from existing asphalt cap sheets? 

thanks in advance


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## English Roofer

resroofer said:


> hi professionals
> 
> -we have a 50' x 85' wood barrel roof lots of slope on our shop
> 
> -it has about about 1" of existing what looks like coaltar and mop on
> which we dont want to remove
> 
> -leaning towards single 50' x 85' 45mil sheet of mechanically fastened epdm
> 
> -95% of our roofing jobs are residential
> 
> what do you guys recommend ?
> 
> should we put a separation sheet over existing cap sheets to keep new epdm from contamination from existing asphalt cap sheets?
> 
> thanks in advance


A photo would really help!
Cheers
Dave


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## Scott Holloway

Very unlikely that your barrel roof is coal tar. If it is not some form of cold applied system it is more than likely asphalt.


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## Ed the Roofer

It can't be coal tar, or else it all would have slid downhill.

Type IV asphalt more than likely.

What does the membrane manufacturer recommend in their specifications manual?


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## 4 seasons

I would definately screw down an iso board, or some insulation board. If your roof is what I am picturing in my head, it sounds like a boatload of fun! not really...but work is work


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## Grumpy

Barrell roofs are no problem for single ply. A cover board and epdm would be fine. YOu may also consider an elastomeric restoration, which I prefer for barrell style roofs. FYI there is a lot of scrap in barrell style due to the shape.


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## Ansel

Nail base and granulated modified ........


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## resroofer

what cover board/sheet do you recommend underneth the epdm and how long will 45mil epdm probably last?

what elastomeric do you recommend and how long will it probably last?


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## Grumpy

EPDM the membrane will last hundreds of years if not more. The seams and details might only last 20 years. Elastomeric is a 10 year when done properly, most people don't do it properly.

As for the cover board, I like fiberboard when people don't want R value. There is a new product I have been wanting to try that is a 1/4" ISO with one surface being trated with a plastic like product. EPS is acceptable if the deck is not wood.


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## BornaRoofer

Fiber board is fine iso is better.

If you use one sheet like you said and glue it down it may last longer than you.

If you mechanically attach it and use batten & cover strips it will start leaking sometime after 10-20 due to the buck water laps every 10'.

If you use smaller sheets and fasten in the seams and don't buck water on any laps it wont leak much if at all even when/if the seams do fail due to the slope of the barrel.


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## SinglePlyGuy

Go with one of the Gyp Boards Mech Attached and a PVC...better aesthetics than an EPDM on a barrel.

Securock or DensDeck will give you a nice surface and help out with fire rating as well.

I have done a lot of barrels this way and they look really good.


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## Grumpy

Lots of cutting on those boards, No? Secure rock and desndeck is expensive and a PIA to work with. I personally wouldn't bother with it unless the customer specifically wanted some kind of fire rating.


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## SinglePlyGuy

I agree it is a PIA to work with as compared to ISO... building departments around here seem to be requiring it more often than not in that application tho.

If code isnt an issue than the new HD recovery boards (100 psi) are pretty sweet... very impressive product.


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## Grumpy

Hey if it's a requirement go for it. The requirement/code should level the playing field. I just wouldn't spec it myself personally unless the customer or code official wanted it.


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## buildpinnacle

No wrong answer here, however, if it's me, and the existing conditions are favorable, I prime and torch a modified. Granulated or smooth depending if you want to fool with coating it every few years. Aluminum coating usually will last 3-5 year depending on the environmental conditions and elastomerics approximately 10 if you spend the money on the good stuff and put it on at the proper millage. I would torch in a granulated, personally. This is the most cost effective way to get a good quality roof. In Texas, you're lucky to put down and EPDM and get 5-7 years before the glue turns to dust due to our UV. Heatwelded TPO is another option. No seam issues, reflective, qualified for the Obama rebate if done this year up to $1,500 and doesn't add any weight. Can be applied over the BUR if a slip sheet is used so the insulation is not mandatory. Without seeing the roof, noone can really give an accurate assesment.


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## resroofer

big thanks to the many intelligent replies

but mainly due to the cost and ease we are leaning towards 30 yr dow corning Duration 30 shingles with grace select ice and water under anything less than 4/12 towards the top of the barrel right on top of existing bur

what do you guys think????


what do you guys think of Duration 30 or what do you recommend instead ?

what do you guys think of grace select ice and water or what do you recommend instead ?


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## Grumpy

Most barrell style roofs usually have compltely flat sections making it impossible to put shingles. Furthermore if it's financial reasons, I can do single ply much cheaper than shingles on a wide open roof. 

Are you a roofer or a property owner? I would think you'd have had this job all specified and estimated by now. I'd also think if youw ere a residential roofer you'd know about shingles and have already formed an opinion of OC shingles and would most likely be specfying your favorite shingle.

Not that I care about helping a property/home owner out, I don't, but I do have a problem mis-representing themselves and it seems as if that's what you may have done.


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## BornaRoofer

Shingle over a Bur? With how long of nails? Sounds wrong to me sorry. Like Grump said epdm can be done a lot cheaper than shingles anyway.


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## kimboy

Barrell roofs are no problem for single ply. A cover board and epdm would be fine. YOu may also consider an elastomeric restoration, which I prefer for barrell style roofs. FYI there is a lot of scrap in barrell style due to the shape.


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## Acubis

*Pvc*

OK worked on lots of these on large commercial projects - your best bet for longevity and quality is a custom manufactured PVC sheet. Last one did was Durolast with ISO underneath order in two sheets ONE onsite seam. Call Duro and give them address of building they will help you.

www.researchroofing.com


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## MGP Roofing

We usually do torch down modified on these, if the H/O wants the shingle look, we do that with I&W under, then the modified on the low slope bit in the center. Mostly its dormers that are barrel shaped but we do get the odd full barrel roof here, in particular the Tongan church people seem to like them done in shingles. worst part is doing the curved ply substrate!


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