TPO vs Rubberized Asphalt

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Author Message slund (Unregistered Guest) Unregistered guest Posted on Tuesday, January 29, 2008 - 05:42 pm:    I've seen several comparisons of TPO with PVC and EPDM, but can anyone direct me to a comparison of TPO and rubberized asphalt? The major garden roof component manufacturers use one or the other and I'd like to know which one is actually more environmentally friendly and why. Thanks. Sharon Lund (Unregistered Guest) Unregistered guest Posted on Friday, February 01, 2008 - 09:12 am:    I haven't had any responses to my post requesting data on TPO versus rubberized asphalt for vegetated roofing systems. Which product is more environmentally friendly? Anonymous   Posted on Friday, February 01, 2008 - 10:57 am:    set up a LEED checklist and do the analysis yourself. "environmentally friendly" isn't usually the first reason that someone selects a roofing membrane, but if that's your criteria, the information is probably available from the membrane manufacturers. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 702 Registered: 10-2002 Posted on Friday, February 01, 2008 - 03:08 pm:    There has been more than 1 thread discussion TPO membranes here - whether compared to something else and not rubberized asphalt there is a lot to lend weight to whether you consider it or not. For a roof membrane, as commented above, 'environmentally friendly' not going to be my prime reason for choosing - it may not even be a consideration. On the other hand, the are some specifics about rubberized asphalt, especially if its Hot Fluid type that can elevate its consideration. One of the prime point relates to its life. Forget warranty, what membrane do you know that can be consider potentially as 'life of the building'. That's just about where it is. I recently entered a discussion with a facility owner who had one of these on his roof that I had done in 1983. He was looking to a roof that would be reflective, both for LEED EB as well as environmental systems savings, so he was talking about going to an EnergyStar reflective single ply membrane with TPO and PVC under consideration. I asked why, was the existing roof leaking, and if not had he talked to the manufacturer of his existing system. The existing system had never given him a problem, so I explained that some of the hot fluid rubberized asphalt manufacturer's (his was in this group) were re-certifying existing roofs with a new warranty after inspection. He could easily stay with the same membrane, maybe have to raise his flashing line, and put down pavers that comply. Even the insulation is highly likely to be reusable. So when a product is looked at for life cycle costing, and when its life is the life of the building, that may mean a lot. Sharon Lund, CSI, CCCA, CCS, LEED AP Senior Member Username: sharon_l Post Number: 28 Registered: 11-2005 Posted on Friday, February 01, 2008 - 03:37 pm:    That's exactly the kind of info we need. We want to spec the best application for the client, while keeping the various criteria for "environment" in mind. Thanks for your input. Anne Whitacre, FCSI CCS Senior Member Username: awhitacre Post Number: 713 Registered: 07-2002 Posted on Friday, February 01, 2008 - 05:12 pm:    the rubberized asphalt may be a real problem to install in some areas. it doesn't necessarily meet a lot of air quality standards, and there are OSHA rules when dealing with hot kettles. in many jurisdictions, it simply isn't possible to use this product anymore, or it will come at a premium. I agree with the value of the product though -- its our first choice for most waterproofing situations. Edward R. Heinen, CSI, CCS, LEED AP Senior Member Username: edwardheinen Post Number: 12 Registered: 04-2006 Posted on Friday, February 01, 2008 - 05:15 pm:    Consider that with TPO, you can probably eliminate the root barrier. Sharon Lund, CSI, CCCA, CCS, LEED AP Senior Member Username: sharon_l Post Number: 29 Registered: 11-2005 Posted on Monday, February 04, 2008 - 01:30 pm:    Thank you all so much for your comments. They have been very helpful to us in evaluating all aspects of spec'ing the best product. Phil Kabza Senior Member Username: phil_kabza Post Number: 301 Registered: 12-2002 Posted on Wednesday, February 06, 2008 - 09:24 pm:    I had a similar chat recently with a project architect who assumed he needed to use a TPO in order to get an adequate SRI for a LEED project. I pointed out that there are surfacing options for BURs and MBs that meet the various "cool roof" requirements. Those systems provide renewability and redundancy not offered by any single-ply membrane. They're more tolerant of foot traffic as well. John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 843 Registered: 03-2002 Posted on Thursday, February 07, 2008 - 08:51 am:    Ed: We just specified a vegetated roof with Carlisle's TPO, and they did require the root barrier. I agree hot-asphalt roofs are very long-lived. I wonder how much of that life is due to them being used in protected-membrane assemblies. Would a TPO last as long in a similar environment? We shall see. Edward R. Heinen, CSI, CCS, LEED AP Senior Member Username: edwardheinen Post Number: 13 Registered: 04-2006 Posted on Thursday, February 07, 2008 - 12:01 pm:    John: Yeah, there may not be a consensus among reps in the industry on root-barriers-for-TPO, so a project-specific approach should be used. Notably, root barriers themselves are made of thermoplastics, including TPO, where the seams are heat-welded.