# Single ply Dibiten or 2 ply App torch????



## RacerX

I need advice for a flat roof that I re-framed to put 8" of pitch over 19ft into. I've been told that a single ply (base sheet, granulated cap) Dibiten torch system is better and last as long or longer than a 2 ply APP torch system (base sheet, smooth, granulated cap). I know that Dibiten is ALSO a torch down system! In my opinion, I would rather spend a little extra money and over kill it , rather than under kill and go with minimums. I live in Southern California, so ice and snow are NOT a problem!!!! But I do not want to mess with this roof for at least 20 -30 yrs!!! (We can hope it lasts this long!) Please. NO advice to go with a BUR (hot mop), PVC, or self sealing type system, I don't think that's going to work for me. So what do the experts think??? Oh, what is the best base for this?? I've been told 25lb, 40lb, 75lb and lay fast or similar type under layment of an SBS type nature. Most guys in my area are going with 25lb. I appreciate all opinions and advice!!


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## 1985gt

Hot mop with a cap sheet. nail a base, mop 3 felts and granulated mod bit. That or a PVC. Seriously you said you would pay more for a better roof and these two are it. Although to be honest a BUR(nailed base 3ply felt and rock) Would be better then a granulated cap sheet but Im guessing your going for looks since its on your home. I'm and expert and thats what I think. Not sure why you don't think these other systems wont work for you. All are very adaptable to any area.


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## Grumpy

PVC, faster, easier, cleaner and since you are in a sun area also highly reflective. 

base sheet + a granulated cap is not a single ply. GAH I hate it when people call modified bitumen single ply. It's obviously 2 plys, the base and the cap. That's two ply, not single ply. I have gotten in verbal fights with many an architect about this. 


I'm not a fan of hot tar although it is a great roof.


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## RacerX

Thanks for the advice. As far as PVC, WAY TOO EXPENSIVE, almost double the cost. I had a hot mop on there originally but the moron roofer didn't use asphalt primer on the edge metal, so water was wicking in from the bottom edge and it destroyed all the plywood and the fascia. Through my research, it appears to me that a modified type system is better than a BUR/Hot Mop. I know that you can also get a modified system with Hot Mop as well. As far as the # of ply's goes, I was under the same assumption, but I've had more than one roofer tell me otherwise! I always thought that the base was considered a ply. Anyways I've decided to go with a base sheet, smooth torch and then cap torch. I would call this a 3 ply system, but like I said, some roofers would still call it a 2 ply system!! LOL LOL This whole process has been agonizing. I've probably met a half dozen roofers and NOBODY has said the same thing. Also there was no consistency in the bids either, low of about $2200 all the way to $7100 for the same type of systems. All the roofers were licensed and have been in business 17yrs or more! I didn't think that I would have to learn how to do there job in order for me to get the right system and also to know what they were telling was correct. But I trusted someone the last time and unfortunately it didn't work out and now I am re-doing the roof again. But I am a little wiser this time. LOL LOL


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## Grumpy

Nope. It shouldn't be double the cost apples to apples. If you are comparing a 20 year modified or hot tar specification to a 20 year PVC specification the PVC should be cheaper. Now if youa re comparing a 10 year or 15 year specification to a 30 year specification well obviously that's not apples to apples. And if you are considering a 10 or 12 year specification on your roof, think again, that'd be ill-advised. 


I don't think many peopel woudl agree modified is a better system. I do not install hot and do isntall modofied on request, and I think hot is a much better roof than modified. 


here are two reads you should consider reading which may make your decision easier... Hire your Contractor and Flat Roofing Options


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## RacerX

Thanks for the reads Grumpy. I've read articles very similar in the past. Where I am, there are few installers of PVC, so right off the bat competition is less, price usually higher. If I used a base and single ply of Dibiten, warranty is 20 yrs. Cost $2900. However, a single ply PVC system, cost is about $5800, BUT it carries a lifetime warranty in residential applications. I would like to go with the PVC, but my finances won't allow it. On the other hand, if I go with a couple of other big name brands, ie GAF, Certainteed and I think there is one more, a base, smooth and cap torch, the warranty can be as high as 20 yrs. Price about the same as the single Dibiten. I appreciate everyones opinion and advice. It make the decision a little easier to make.


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## 1985gt

The person who installed that but did it wrong. Even if they didn't put primer on the metal the felts underneath should have wraped over the edge of the fascia. Any roofing system is only as good as the installer. Have you thought about EPDM you can get it in white also. Torch downs are good roofs don't get me wrong but we haven't installed on in 10 or more years. Too much liability others say hot is to much liability but your guys prefer the hot system. His big is this roof?


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## Grumpy

RacerX said:


> Where I am, there are few installers of PVC, so right off the bat competition is less, price usually higher.


 Exactly why we are specializing in single plys. Too many hacks buying modifiued from home depo and killing that market. Plus the liability.


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## Grumpy

1985gt said:


> The person who installed that but did it wrong. Even if they didn't put primer on the metal the felts underneath should have wraped over the edge of the fascia. Any roofing system is only as good as the installer.


Yes, a very very common problem I see from ALL roofing systems is improper edge detail. It takes longer and takes more material to properly treat the edge. Hmmm I wonder why it gets so neglected. LOL 


We do very little torch work anymore and don't do hot. The reason? Liability, insurance, etc... Which has a higher liability? I don't want to find out


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## 1985gt

Grumpy said:


> We do very little torch work anymore and don't do hot. The reason? Liability, insurance, etc... Which has a higher liability? I don't want to find out



Thats easy Torch  harder to burn down a building with hot asphalt compared to a open flame.


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