# tpo over tpo?



## Grumpy

I took a look at a job yesterday. It is a 5 year old failed TPO roof, due to idiot installers. It is a small church and they have been promised free membrane by the manufacturer but the accessories and labor is on them. 


The existing roof is fully adhered 45 mil TPO. Rather than redo all the tapered insulation I'm wondering if simply cutting the existing TPO and fully adhering a fleeceback over it would be acceptable?



How would you spec this?


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## 1985gt

Were doing one similar that the TPO Failed after 8 years and the manufacture is doing a lay over. Instructions were to cut the existing TPO in 5' squares and M/a a new sheet on top. I don't know if glue or any adhesive would hold well to the top of the old TPO sheet. I kind of highly doubt it will.


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## Grumpy

Yeah that's my thought as well... Well BA should hold fine in theory, I mean it stick great to the bottom side of the TPO, and if you were to do a FA Fleeceback, that might work.

I thought about a cover board set in low rise foam but none of my research shows that it'll stick, so that's out. It looks like it's going to be a complete tear off, or mechanially attached tpo over the existing tpo. 


I think rather than stress over it I will just bid it for a complete tear off, and if they need to save cost I'll bid a layover of some kind and worry about it then. 

I just hate jobs with tapered insulation :wallbash: and besides hate to have to throw out all that existing insulation.


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## 1985gt

I don't know why you hate tapered ISO so much. It's a cake walk. The hardest part is laying it out on paper, its a walk in the park in the field.


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## linderman

why not fasten down a high compression recover board over the tpo roof after you have cut the crap out of it to prevent moisture build-up

I would not advise complete tear off; especially not for a church i this economy.

but regardless quote them 

Best = rip off

economy = recover


BTW: forget using BA and adhering a new membrane over the existing tpo; thats a disaster, I have tried it ..........there is no place for the gasses to escape from the bonding adhv unlike polyiso where the gasses can be absorbed by the iso


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## RoofYourWorld

Grumpy, 

Does the TPO system have to be fully adhered? 

I've had success with projects where I lacerated the original membrane at the seams, walls and penetrations then mechanically attached a new membrane.


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## rooofer1

Hello, I've done it before. There was no TPO, it was FPO (flexible polyolefin) of Sarnafil Sika. The FPO was stuck. We have a liner made ​​of felt, fleece and down between fixed mechanically with the new railway tracks. It has never been any problems. The surface was concrete and thermal insulation (polyurethane). The old railway TPO but all we had previously cut. It was an office building.
Bernd


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## Grumpy

1985gt said:


> I don't know why you hate tapered ISO so much. It's a cake walk. The hardest part is laying it out on paper, its a walk in the park in the field.


 Too muchc utting, too much wasted time, too much wasted material, too much lost production, not enough squares being put down in a day... and I just hate jig saw puzzles. The only tapered I like is when there are no valleys and peaks. When I see a tapered job with valleys and peaks I know the production will be half what it would be with flat insulation. 

Plus I don't enjoy jig saw puzzles, and that's what a tapered system is.


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## Grumpy

RoofYourWorld said:


> Grumpy,
> 
> Does the TPO system have to be fully adhered?
> 
> I've had success with projects where I lacerated the original membrane at the seams, walls and penetrations then mechanically attached a new membrane.


Here is the deal. I was approached by a general contractor/ insurancde restoration contractor. This is a big global insurance restoration company. The guy really knows nothing about nothing as far as I can tell but seems like a good guy. When I asked him about his background he was telling me he used to be an insurance adjuster.

So why was he contacting me? Because I am certified by the manufacturer and the manufacturer agreed to pay for the membrane only if they used a certified contractor. IN all honesty it's not their fault, but I suppose they just wanted the lawyers to go away.

Anywho, when I asked him for a spec or scope, what he showed me was meaningless jibberish. His exact words to me were "just do a normal tpo system." I tried to explain it's not like sloped roofing there are numerous variables and really no such thing as normal. I asked if he wanted a tear off, a lay over, reuse or replace copings, what? Lots of shrugs and non answers. He has no idea. This is why I am so perplexed I have zero guidance and a level of seperation between myself and the true decision makers that I can't get answers to my questions. That's a large part of the reason I hate being a sub. 

Mechanically attached seems like the easiest and simplest. FA is often much better especially when it comes to lay overs since it limits horizontal water migration. 

In this case I just bid the thing for a tear off, and replace everything except the coping. I probably bid too high as I always do when I see a taper job.


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## Grumpy

linderman said:


> why not fasten down a high compression recover board over the tpo roof after you have cut the crap out of it to prevent moisture build-up
> 
> I would not advise complete tear off; especially not for a church i this economy.
> 
> but regardless quote them
> 
> Best = rip off
> 
> economy = recover
> 
> 
> BTW: forget using BA and adhering a new membrane over the existing tpo; thats a disaster, I have tried it ..........there is no place for the gasses to escape from the bonding adhv unlike polyiso where the gasses can be absorbed by the iso


Nothing wrong with the economy. Stop listening to the media  I'm seeing help wanted signs damn near every where I go. As for the economy dictating my spec, that's never really played a factor in the specifications I write. I usually try to do what is right for the building. What I tell people then is if you can't afford it, let's do some temp repairs and wait until you can afford to do it right because I'd hate to see you do it thrice.


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## 1985gt

Grumpy said:


> Too muchc utting, too much wasted time, too much wasted material, too much lost production, not enough squares being put down in a day... and I just hate jig saw puzzles. The only tapered I like is when there are no valleys and peaks. When I see a tapered job with valleys and peaks I know the production will be half what it would be with flat insulation.
> 
> Plus I don't enjoy jig saw puzzles, and that's what a tapered system is.


Sure it takes a bit longer, but you charge accordingly. Almost everything around here is has some kind of tapered ISO on it. Once you do it you get quicker and find little short cuts. 

You can also buy precut valleys and such I have no idea how much it cost I would guess a lot more then if you cut them your self..


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## Grumpy

Yeah I charge accordingly, often I purposely price myself out of the ball game when there is taper iso so if I get it I know I won't lose, but that doesn't limit my liability, doubles my night seals, doubles the overhead (because 2x the number of days) etc... It's just a complete waste of time and money not to build it right in the first palce and structurally slope everything. Cheap ass bastard engineers and builders.


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## RoofYourWorld

Grumpy said:


> Yeah I charge accordingly, often I purposely price myself out of the ball game when there is taper iso so if I get it I know I won't lose, but that doesn't limit my liability, doubles my night seals, doubles the overhead (because 2x the number of days) etc... It's just a complete waste of time and money not to build it right in the first palce and structurally slope everything. Cheap ass bastard engineers and builders.


I'm with you, Grumpy - you've got to do what you KNOW is right on the front-end.

Seems like the "value-engineering" engineers and/or builders who go the cheapest route are the biggest pains in your a$$ when the job is done (exactly like they asked) and they see why you had recommended certain things in the first place!


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## Grumpy

I was discussing with a builder once about sloping the roof. He said it would cost him double to slope the steel roof framing than it would to taper it with insulation. I explained cost of ownership and a 50 year life cycle etc... He didn't care. Then I commented, "Why can' the joists just be factory sloped and craned into place like residential truss systems?" Deer in the head lights <blank stare>.


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## 1985gt

Grumpy said:


> Yeah I charge accordingly, often I purposely price myself out of the ball game when there is taper iso so if I get it I know I won't lose, but that doesn't limit my liability, doubles my night seals, doubles the overhead (because 2x the number of days) etc... It's just a complete waste of time and money not to build it right in the first palce and structurally slope everything. Cheap ass bastard engineers and builders.



DOUBLE!  I would guess that would price you right out of the ball game. Honestly when you get proficient at it does not take that much longer then laying down flat, definitely not double. I will say it takes a lot more time drawing it up and figuring screws, ect. in the office though.


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## Grumpy

Yup double. When you think about it you can sometimes be laying double or triple the number of pieces of insulation. We did one once which was 85' sloped from front to back, no valleys or ridges, that certainly did not take twice as long but once you have to start laying out marking cutting etc, our overall daily output is reduced by half. 

Screws actually aren't that bad. The last job we did I figured out a pretty neat short cut that came out pretty accurate. Basically what I think I did was to figure out I needed 5 lengths of screws on this particular roof. So what I did was figure out the total number of screws and multiplied by .2. So let's say I needed 1,000 screws total, I needed 200 6", 200 8" 200 10" etc... Then I added the linear footage of my perimiters and used the longest screws for that, which happened to be 12", and done. It worked out pretty good in this case anyways. I'll have to try a few more times to know for sure.


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## shazapple

It's true, the lack of sloped deck is my biggest gripe while reviewing the drawings for new buildings. Flat is so much easier, cheaper, and a more uniform R-value.


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## RoofYourWorld

1985gt said:


> I will say it takes a lot more time drawing it up and figuring screws, ect. in the office though.


I was lucky enough to have worked with a manufacturer who did this part for/with my estimator! He was "dead on" every time... Needless to say he got all of my business!


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## Grumpy

Alot of our suppliers will do the take offs for us. On smaller jobs I just figure it out since I hate waiting days to get taper package quotes back. However come to think of it, they don't include fasteners. Hmmm.


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## 1985gt

Depends on the job, I generally draw it up my self unless its public bid work since the architect has basically done it for you I will have the supplier or manufacture do the tapered. I've never gotten fastener counts from them. Heck I honestly have never even thought to ask.


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## Grumpy

1985gt said:


> Heck I honestly have never even thought to ask.


 Me either until yesterday but you can be sure I'll ask from now on 



As for the design Yes, GT, I'll usually do the design, but I let the supplier figure the materials list as far as taper and fill. 

One time I did not do the design on a rather complex roof and 3 suppliers sent 3 different designs.


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## RoofYourWorld

Grumpy said:


> Me either until yesterday but you can be sure I'll ask from now on .


Amazing what you can get just by asking!


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## 1985gt

Grumpy said:


> Me either until yesterday but you can be sure I'll ask from now on
> 
> 
> 
> As for the design Yes, GT, I'll usually do the design, but I let the supplier figure the materials list as far as taper and fill.
> 
> One time I did not do the design on a rather complex roof and 3 suppliers sent 3 different designs.



I'd almost feel bad asking them to do the take off on something I designed, since we would more then likely pull the material out of stock for the job anyway. 

I should have sent in this crappy one I'm doing right now though. 70+ sqs of a badly designed roof. Oh well such is life.


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## Grumpy

For me stock is partial rolls and scraps I can't return. Anything full gets returned to the suppliers unless I have a job coming up immediately within the next few days. I've got a half a roll of damned near everything you can think of laying around in my garage and storage van. My wife is on my ass to get rid of the van and I agree with her, I am so emberrased to be living like a hill billy roofer. I used to pride myself on the fact that when I come home I see nothing that has to do with roofing except the roof on my house, that aint the case anymore. 

I don't have a warehouse so I let the distributors do that for me. Yes if I was just using them to give me a material list with no intention of purchasing, I too would feel like an ass.


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## 1985gt

We have been blessed with a nice warehouse and office building. We generally buy a truck or so every now and again. We will stock the normal stuff, 1.5" 2" Iso 1/8", 1/4 and 1/2" tapered, cover board ect. EPDM TPO and the tapes to go with it. If we get a job/s and it doesn't fill out a full semi we will add to the order to fill it out. Its funny how many 1/2 rolls of cover strip we have. Its like the crew/s don't know where the partial rolls are and dig in to a new box for 20'. It has been getting better but still could be a lot better. Luckily the repair guys use it up pretty quickly.

Maybe the boss is using it as a retirement plan. :laughing:

If your ever down in my neck of the woods come have a look around. It's not the biggest place around but it works for us.


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## Billy Luttrell

1985gt said:


> We have been blessed with a nice warehouse and office building. We generally buy a truck or so every now and again. We will stock the normal stuff, 1.5" 2" Iso 1/8", 1/4 and 1/2" tapered, cover board ect. EPDM TPO and the tapes to go with it. If we get a job/s and it doesn't fill out a full semi we will add to the order to fill it out. Its funny how many 1/2 rolls of cover strip we have. Its like the crew/s don't know where the partial rolls are and dig in to a new box for 20'. It has been getting better but still could be a lot better. Luckily the repair guys use it up pretty quickly.
> 
> Maybe the boss is using it as a retirement plan. :laughing:
> 
> If your ever down in my neck of the woods come have a look around. It's not the biggest place around but it works for us.



Haha today was the 1st day in I do cannot recall how long that I had to buy a roll to do a repair....seems I have partial rolls in every corner and crevice in the warehouse...until today!


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## LCG

An amusing thread no doubt,

My achellies heal is ridge vent. Yes, Ridge vent.

I have at least 25 rolls of ridge vent? What do I order more of on every job? YEP, RIDGE VENT


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