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I have a balcony on two sides of the tower in my home. It's had a peel and stick roof for the past few years (GAF Liberty) waiting for me to have the time to install a more permanent solution.

I'll remove the current roofing and decking to the joists and start again. Originally I intended on using soldered seam terne coated steel and I have the steel and accessories in stock, but now I'm not convinced it's the best choice. Once roofed, I'll install a deck surface on sleepers. I'll integrate the guardrails to the deck assembly to avoid roof penetrations. The deck water proofing material will wrap up under the siding to act as flashing.

I'm leaning toward fully adhered TPO or to the JM liquid applied membrane.

Do any of you have a better solution?

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TPO is what I'd put on 6 acres of GM factory roof or similarly large scale operation.

Of course TPO would work, but I just don't like it for small stuff needing fine tuned details. Not a fan of spreadable roofing either. I know it works, but it isn't for me.

Personally, I'd go torch mod bit (APP, not SBS) and sheet metal flashing details. (Unless I got the general image wrong.....got any pictures?) There's hundreds of square miles of mod bit in Chicago, I know how to work it, and I'm most comfortable with it.

Go with your skill set, I always say.....

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If the sleepers are easily removed and you've a consistent downward slope towards the drains, I'd go with TPO because you can change it yourself when needed. It's not labor/equipment intensive.

Marc

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If you are going to use it as a walking/deck surface I recommend fiberglass. We use it on houses and it performs well. The hardest part is finding someone that knows how to work with it and install it.

I clearly remember one of my professors in architecture school telling me that there is only one place that flat roofs don't leak and that is where it does not rain.

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The professor is living in the past. The roofing industry figured out every last problem with flat roofs 30 years ago. The problem is with installers. Chicago is nothing but flat roofing. Do it right, which isn't hard, they last forever nowadays.

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The professor is living in the past. The roofing industry figured out every last problem with flat roofs 30 years ago. The problem is with installers. Chicago is nothing but flat roofing. Do it right, which isn't hard, they last forever nowadays.

I am not a fan of flat roofing and I'm not nearly as experienced as you with flat roofs but I find "Do it right, which isn't hard, they last forever nowadays." really hard to believe unless you mean "with proper maintenance" to be added to that statement.

Not trying to be argumentative, trying to learn. Please expound.

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I am not a fan of flat roofing and I'm not nearly as experienced as you with flat roofs but I find "Do it right, which isn't hard, they last forever nowadays." really hard to believe unless you mean "with proper maintenance" to be added to that statement.

Not trying to be argumentative, trying to learn. Please expound.

They don't even need maintenance. I'm looking at buildings now that I looked at 28 years ago with the same damn roof system. They're fine. Forget the myth of statistical lifespans.

First and foremost.....Roof Design. Yes, roofing needs to be designed. It's not complicated. The single best book I've ever found on this topic is "Problems in Roofing Design", but McCampbell down in Tennessee. Of course, it's out of print. Design flashing details correctly, they work.

Second.....Drainage. Roofing performs as well as it drains. Flat roofing has to drain. 1/4" per foot is fine. Even 1/8" is fine. Just make sure it drains.

Third.....Installation details. It's not hard. Follow the instructions on the pack. 26 gauge keynar coated galvanized sheet metal for all flashing details. We order custom profiles from a CNC sheet metal shop. Sheet metal flashing rules. Follow the specs that every mfg. has for their materials, which if you collect a lot of them, you start seeing are all the same thing. Prime all sheet metal before heat welding to it.

That's it. It really isn't complicated. Stuff lasts forever. Of course the mfg. and installers like you thinking that there's a statistical lifespan for their material. Of course they do.

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Fully adhered, 90 mil EPDM. From a longevity standpoint, the only thing that compares to it, in low sloped roofing, is 4/5-ply coal tar pitch (30 years). It's user friendly, doesn't require expensive specialty tools to install and plenty of pre-made flashing details.

For Gods sake no. It's not user friendly. It's about as non-user friendly a material there is. Ex roofers all like EPDM for some reason. Cary is an ex roofer.

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Fully adhered, 90 mil EPDM. From a longevity standpoint, the only thing that compares to it, in low sloped roofing, is 4/5-ply coal tar pitch (30 years). It's user friendly, doesn't require expensive specialty tools to install and plenty of pre-made flashing details.

For Gods sake no. It's not user friendly. It's about as non-user friendly a material there is. Ex roofers all like EPDM for some reason. Cary is an ex roofer.

Uhhm, yea...cause it works!

The first part of my roofing life, I worked for a company that installed mod bit, BUR and CTP. We always thought single plies (EPDM, PVC & TPO) were garbage. Mostly because we were always fixing problems with them. With EPDM/TPO, it was installation issues and with PVC it was installation issues and material defects.

The last part of my roofing career was with one of Carlisle's biggest installers in the country. EPDM is a fantastic product. You can line a swimming pool with it. Seriously.

The installation problems we see in the HI biz is mostly caused by installation issues, but it's not complicated to install. In fact, if you can do peel & stick, you can do fully adhered. Instead of peeling, you just gotta roll on your own glue.

The real decision on what type of roofing to use, depends on the structure. You wouldn't want to put mod bit or BUR on less than 1/4"/ft slope, but you can put EPDM there. If the deck is going to be close to the roof, prohibiting sun and air movement, causing longer periods of standing water, stay away from mod bit.

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If the sleepers are easily removed and you've a consistent downward slope towards the drains, I'd go with TPO because you can change it yourself when needed. It's not labor/equipment intensive.

Marc

It is labor and equipment intensive. Don't you use air welders down there when applying TPO? You'd put a deck on TPO? Really? We'd take a material with barely a decade of market introduction and trust it?

"Because you can change it yourself when needed"......Why would anyone choose a material that required changing?

I'll say it one more time. Mod Bit. It's unglamorous. It's sold by orange aproned aisle monkeys. It's the hack material of every gap toothed jack legged moron roofing mope in the world. We all see it slammed and jammed in the most idiotic manners imaginable and we all see it leaking and ponding and...and...and....

And it's cheap and easy to install. A hundred dollar torch, a knife, and a fifteen dollar masons trowel are all the tools you need. It can take a deck load.

Folks unfamiliar with flat roofing go for all the exotic materials thinking high tech fancy material is the magic. Wrong.

We fix stupid crap on really expensive yuppie houses with flat roofs in Chicago where it goes from 20 below zero to 105 in 5 months. We use modified for all the reasons everyone else seems to think are bad. It welds to heavy gauge sheet metal flashing superbly. It forms into all sorts of shapes. There are a multitude of pre-made boots and details readily available if only one knows where to look. We put this new aluminized coating on it that's almost like a galvanized finish; approved for loads and traffic. Stuff lasts forever.

But, don't take my word for it. Use the high tech stuff. All the folks with minimal experience in flat roofing think it's cool, so it probably is.

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Oh yeah.....and Bison Deck Support Systems

And Dow 790 and 795 Silicone for fine tuning.

Everyone here should hang around with architects that do schools and hospitals. Find the project manager/architect in the firm in charge of roofing details. They know. They're the only folks I can talk to about this stuff without getting a major burr in my ass.......

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If you want to put a deck over it modified bit. is probably the way to go. If you want to walk on it directly I like fiberglass. You would have to find a qualified installer, or you could do it yourself. But there is probably nothing worse to work with than fiberglass (polyurethane glue and foam would be a close second).

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First, TPO has been around for about 25 years, not ten. I inspected an American Legion Hall with a 60 mil TPO roof that was installed in 1991 and it's still perfectly fine. Flexible, good surface and intact flashings. It's the reason I was leaning toward the product. I admit I am apprehensive about doing heat welded seams.

I've installed acres of torch down mod bit. I'm really familiar with the product but it does deteriorate if it stays wet and I'm afraid there will be a two inch mulch layer of maple samaras between the deck and the roof.

With EPDM, I always see the transition over and up the cant pulling away and stretched like a drum skin. And, with an L shaped balcony there'll be a seam pulling in shear.

Tom, I paid $900 for the 26 gauge, terne and a couple boxes of clips. I'll sell it to you for your porch roof. Or, I'll die and it'll still be taking up floor space in my tool room and my kids will toss it in the trash.

Steven, I have a fiberglass skill set and I just watched YouTube videos from some guy in England. (fixmyroofUK) I think that's the ticket for me. Do you know where I can buy the pre-made flashings?

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First, TPO has been around for about 25 years, not ten. I inspected an American Legion Hall with a 60 mil TPO roof that was installed in 1991 and it's still perfectly fine. Flexible, good surface and intact flashings. It's the reason I was leaning toward the product. I admit I am apprehensive about doing heat welded seams.

I've installed acres of torch down mod bit. I'm really familiar with the product but it does deteriorate if it stays wet and I'm afraid there will be a two inch mulch layer of maple samaras between the deck and the roof.

With EPDM, I always see the transition over and up the cant pulling away and stretched like a drum skin. And, with an L shaped balcony there'll be a seam pulling in shear.

Tom, I paid $900 for the 26 gauge, terne and a couple boxes of clips. I'll sell it to you for your porch roof. Or, I'll die and it'll still be taking up floor space in my tool room and my kids will toss it in the trash.

Steven, I have a fiberglass skill set and I just watched YouTube videos from some guy in England. (fixmyroofUK) I think that's the ticket for me. Do you know where I can buy the pre-made flashings?

No I don't know where they buy the materials. Maybe you can check with a local boatyard to see where they buy their fiberglass supplies.

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The professor is living in the past. The roofing industry figured out every last problem with flat roofs 30 years ago. The problem is with installers. Chicago is nothing but flat roofing. Do it right, which isn't hard, they last forever nowadays.

I graduated architecture school 25 years ago! Maybe he has changed his opinion.

In my experience I see a lot more problems with flat and low sloped roofs than with steeper pitched roofs. The detailing of flashings and roof maintenance requirements are important and often done poorly.

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Certainly, low slope roofing offers more opportunities for problems. But, everyone's got it wrong, including Fabry. It doesn't matter how many acres he's applied; what he's saying indicates he's not aware of a few things about mod bit.

The observations about EPDM are spot on. It's always pulling like a drum skin someplace or another, and shear delams are common. It's the stuff one puts on 12 acres of GM factory roof, not a tight little bay roof under a deck. Same with TPO. I've heat welded enough seams and seen it come apart in enough situations that I don't care about old American Legion Halls holding up OK. It's an American Legion Hall, not a bay under a deck. TPO as a material is a miracle; it's getting it to all lay down sweet and clean that's gets problematic. Especially on a little bay roof under a deck.

Fiberglass works. The problem is working with fiberglass. Anyone every done a layup on a boat? The flashing components are problematic in curiously interesting ways.

But, go ahead. Use fiberglass or TPO. Experiment. I love other people's experiments.

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Steven, Resin and mat are no problem. I used to buy resin in 55 gallon drums and mat by the 100 meter roll. I need the flashings.

Kurt, you haven't shared what you know about mod bit that I do not know. I know that between me, my dad and my brother in-law we owned about 80,000 sf of it. I agree, it's an awesome product- I just think for this application there may be more durable, less pervious options to explore.

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The balcony is 16 feet long on the side in view and 14 feet long on the other side. Both sections are four feet deep.

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Steven, Resin and mat are no problem. I used to buy resin in 55 gallon drums and mat by the 100 meter roll. I need the flashings.

Kurt, you haven't shared what you know about mod bit that I do not know. I know that between me, my dad and my brother in-law we owned about 80,000 sf of it. I agree, it's an awesome product- I just think for this application there may be more durable, less pervious options to explore.

Click to Enlarge
tn_201562411113_unnamed.jpg

68.69 KB

The balcony is 16 feet long on the side in view and 14 feet long on the other side. Both sections are four feet deep.

16' x 14' with EPDM = 0 seams in the field.

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Well, apparently there's something you don't know. Here's where everyone's missing the boat. Go back to #1 in my other post.

Design the roof. If, after designing the installation and carefully considering all the variables, sketching flashing, and getting it all on paper, THEN one chooses material. If you had said "I've sketched out all the details, here they are, and I'm thinking of TPO", I might have another take on this.

Choosing material and then designing the roof is backasswards. It's how roofers do it. They got a product, they force that product into contortions. I don't recall anyone talking about their design.

Depending on the design, I might choose any of the materials under discussion. EPDM, TPO, PVC are great for large open applications with lots of access. Small, concealed areas, lots of angles and vertices, drip edges, decks on top, etc., etc.....that calls for something else.

The whole idea of design is lost on everyone, including me, until about 17 years ago when I was schooled on how to actually think about roofing.

The industry reinforces this with all the emphasis on materials, not design. That's why I said get tight with a PM that works for a large firm that does hospitals or schools; those guys get design, and by association, material selection. A large scale project I had the opportunity to visit recently scrapped TPO in favor of two layers of mod bit due to a bunch of hard to access details. Redundancy is lousy in some things, but its pretty darn cool with roofing.

Everyone gets hung up on materials, and then they figure out design. Backasswards.

So, there is something more to know than what's already in one's head.

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