Just need to confirm something before I put it into a spec.
I’m specing TPO for the roof of my project and need to confirm that asphaltic products are a possible danger to the membrane. That is what I have seen from a source I can’t make heads or tails of.
Can anyone set me straight please.
There are fleece-backed TPO materials, some engineered to be set in asphalt, others in urethane adhesive. I heard talk of cold-process asphalt setting systems a couple years back but I don’t know that it was ever developed for fleece-back TPO. The intent whether hot or cold is to allow direct application over existing BUR.
I’m not a big fan of TPO usually so I won’t go further. I’d get in touch with your Carlisle or Firestone rep.
Good luck!
Ken, I’m with you. Not a big fan of TPO either.
My preferred system is cold-applied 2 or 3-ply SBS Mod. Bit. If I have to specify a single-ply membrane system, then I go to SikaSarnafil.
Thank you guys, but I don’t have a choice on the TPO, Its the client’s material of choice.
I just need to make sure if there is a problem with asphaltic materials and TPO I don’t write it in.
A former employer once told me that nothing made him happier than to have the Client tell him what type of roof to specify. He just made sure he had the CYA letter in the file.
Margaret, see if they’ll spring for an SEBS modified mopping bitumen (I like Barret but Hydrotech and others make it too). That will give you much of the waterproofing you need. Of course it costs more than standard bitumen. Use the standard bitumen for mopping down the insulation, unless of course you’re using something like EPS or XPS.
Well, I use TPO all the time out here in the west. Our single ply of choice used to be EPDM, but TPO is workable in slightly lower temperatures (about 8 degrees more), and when it first came out, it was in 12’ rolls, while EPDM was only in 6’ rolls. That meant fewer seams, which is always a good thing. Now they both come in 12’ rolls. I never specify anything less than 60 mil, and if I can afford the 80 mil white, I’ll go with that on a job. I haven’t used a modified bitumen in ages, but I’ve been told they are still pretty common in the southwest. (SoCal and Arizona, particularly)
oh, as for the “asphaltic product” issue: it varies by membrane type. just have them do whatever is necessary to achieve the manufacturer’s warranty, and make sure there is an inspector on the job site.