Another low slope roof question


#1

I have a small addition on my house with a low slope roof and I need to
redo it. It is 18 feet by 6 feet.

I am thinking about using the gaf liberty tpo self adhering system. It comes in 10 ft. wide rolls so I won’t have a seam. Does this sound like a good option?
Also how much slope do I need in the roof to use this system?


#2

tpo’s require a little bit of applicatiom skills.how were you planning on doing your edge details?what substrate are you adhering to?is ther a gutter?are there walls?


#3

Saw no answers so I thought I’d give ya something. Though I didn’t know there was a self adhering TPO on the market, self adhering is perfect for a diy’er and TPO is a material that lasts a while. What are you roofing, a farmers porch or something? Sounds like it by the dimensions. Without knowing the roof or the materials, I still feel confident in saying the product youre planning to use sounds fine. Just read all the application instructions, as these roofs are meant to have a base sheet etc. and are not meant to be stuck down to another roof or the decking directly. If you post a picture I can tell you if you should attempt it based on any flashings on the roof…


#4

Here is a link to a picture of the project I am asking about. As you can see whoever did the addition didn’t do me any favors. I am replacing the skylights with ones that are a foot smaller in length so that they do not end up where the two roofs come together

static.flickr.com/116/254326417_ … 4e.jpg?v=0


#5

i don’t know what your abilities are, but… skylight flashing, shingle repairs (not to mention pulling apart a valley). If you’ve never done a roof this isn’t a good one to start on with any material. That is my advice. This isn’t redecorating like new sheetrock and trim in your house where if you make a mistake you just wasted a piece of moulding… you can ruin a lot of things under there and still end up paying a roofer to do it.


#6

skylights?
better be a good roofer.

gweedo.


#7

$10 says it leaks when he’s done


#8

[quote=“gweedo”]skylights?
better be a good roofer.

gweedo.[/quote]

Not only a skylight, but a row of skylights! :mrgreen:


#9

TPO is a great roof, but if you aren’t skilled with a hot air welder and know how to detail the corners you are in for trouble. By the way, you better clean off and/or put insulation on the deck before you try to install a self stick membrane. I think the $10 bet is safe.


#10

call a roofer


#11

How long has TPO been on the roofing market?


#12

The only one I ever put on is Sarnafil, company has been making it since 1962 according to their website. You only have to install ONE correctly to see its a superior product. They don’t sell to just anyone, either. You have to prove you know what your doing, and if you have employees, a certain percentage of them have to prove they know what theyre doing.


#13

I think Sarnafil is one of the few thermoplastics that I would use on my own building if I owned one. However, FWIW, Sarnafil is a PVC thermoplastic not a thermoplastic polyolefin (TPO). Still, you know from an earlier post of mine that I am a fan of Sarnafil when it comes to single-ply roof systems.


#14

TPO for roofing since 1962?


#15

I think he was lumping all thermoplastics together as TPO’s, not realizing that the PO stood for PolyOlefin, since Sarnafil is a PVC thermoplastic. Still, I have to agree with him in the fact that Sarnafil is an awesome single-ply.


#16

lost me.

gweedo.


#17

[quote=“Cerberus”]

I think he was lumping all thermoplastics together as TPO’s, not realizing that the PO stood for PolyOlefin, since Sarnafil is a PVC thermoplastic. Still, I have to agree with him in the fact that Sarnafil is an awesome single-ply.[/quote]

ya got me. I didn’t realize there was any difference. Only installed Sarnafil, never any other thermoplastic roof.


#18

Just so you know, I wasn’t trying to “get ya.” I just figured you made no distinction between PVC and TPO thermoplastics.


#19

I don’t know the difference. Can you tell me? I’m genuinely asking you, I’ve been told that the TPO’s are not as good…


#20

They are somewhat close in that they are both thermoplastics. PVC is obviously polyvinyl chloride, where TPO is thermoplastic polyolefin. They are generally manufactured in the same manner, they both are heat weld, and they come in the same thicknesses. The PVC membranes are soft membranes to begin with, but become stiff as they age. TPOs start off stiff, and remain that way. The big difference is that TPOs, unlike PVC membranes, don’t become brittle due to loss of the plasticizers from prolonged exposure to ultraviolet radiation, and TPOs are cheaper to manufacture. So, consider TPOs to be just like PVCs, except they don’t become brittle with age like PVCs, and they are cheaper to make.

FYI, they are making TPOs that are peel-and-stick with welded laps, fleece-backed TPOs for mopping down with asphalt, and of course they too use heat-weld laps.

I hope that answers your question. Just think of TPOs as being similar to PVC, but not having problems like the old Trocal roofs had with regard to plasticizer loss. Of course, Trocal is the worst example of PVC, and those membranes were made before they found out it needed to be reinforced and required UV protection.