What experience have you had with Duro-Last?
I’ve never specified it or gotten it on a project that I know of.
Typically I limit my PVC selection to Sarnafil with an alternative for FiberTite (KEE).
They have done quite a bit of work in our area, and I have specified them on a few projects. Their marketing is primarily to owners and facility managers although I have seen them around a bit more in the last few years.
I’m with Ken. However, I did have the rep visit me at my former firm, but they weren’t included in my spec at that time.
They have a good presence in northern California, when I was working on school’s. Their product seems to be pretty good, and the contractors I worked with seemed to be okay with it also, but I don’t have any length of time with it. Though I have to admit, it is very hard to veer away from Sarnafil, which has never ever failed me.
Peter, you say their marketing is primarily to owners and facility managers, which reminds me of the approach taken by Garland, Hickman and Tremco (for roofing, not sealants). Would you put Duro-Last in the same category as those firms? Was Duro-Last ever specified or included at the owner’s request? Would you care to characterize your experience with Duro-Last? Thanks.
I used Durolast once on a school project here in Michigan. The school system insisted, as they want to try them out on the small addition. At the time (15 years ago?), Durlast was not thought of as a higher quality roof. Typically, their membrane thicknesses were less than everyone else - or so I was told by the older mentors in the office. Maybe they have changed, but I have not run across them in any of the other firms I have been with in Michigan as being equal to the typical membrane roofs.
Its true, they don’t compare well in terms of absolute numbers. but they had some other compelling quantitative info. I’m no longer with the same firm and don’t have access to my old notes and emails, so I cannot elaborate, but I can confirm that they are thinner than the G410 Sarnafil materials
Nathan, I believe that you are mistaken.
We have a long-term client that has insisted on Durolast systems for every project we have done for them. I have found the Durolast system to be every bit as good as Sarnafil and Fibertite (which I also specify frequently) component by component as well as overall durability. This client has Durolast systems down that have been in service for more than 15 years, without issue. Tech service from the local rep in my area (West Coast) is top notch.
How does that conflict with anything I’ve stated? Are you rebuking the concept that their mil thickness is different than Sarnafil? The product rep that I worked with a few years ago was adamant that Dura-Last 50 mil was superior to Sarnafil 60mil G410 felt backed. Using my calculator, it would appear that 59 is thinner than 60, this, they don’t compare will in absolute numbers.
But keep going, I can play semantics games all day long.
In my area (midwest) they also tend to concentrate their sales on the Owner and not the designers, or the installers for that matter. They have tended to stay away from the suburban and city markets where there is an architect more often involved. In outlying areas they sell directly to schools without any outside interference from designers. They have even provided a “public bid” turn-key approach for some schools by specifying the system, putting out the bid packets, collecting the bids and then selling their product to the low bidder.
They also appear to be doing a hard sell on the virtues of a white roof for energy savings but in our area the majority of the old schools that this product goes on are not air conditioned and are not occupied in the summer anyway.
In a slightly off tangent subject the Jan/Feb issue of Commerical Building Products magazine (page 20) there is reference to a Stanford University study that concluded that on average,white roofs increased winter heating demand more than they decreaed summer AC loads. As always the key factor is location,location location.
@Robert - yes, but it’s more like they would like to be in the same category as other roofing companies you mentioned.
@Nathan - I recently did a project where Duro-Last threatened to challange the spec for a public project, insisting that their 60mil was equal to the preferred product’s 80mil membrane.
And I quote from the letter that DL sent: “The decision not to except our membrane is being made without understanding by your client of materials. Again, our Duro-Last membrane is constructed with superior reinforcement and balance of membrane to provide in service performance to meet required warranty requirements. We produce a superior membrane, thicker does not equate to better. Better engineered makes a superior membrane.”
So, I ended up having to include it as an ‘approved equal’ in the specs, much to my annoyance.
Fortunately, no real horror stories. About all I knew about Duro-Last was that they deal directly with owners, which brought to mind a couple of other companies that have been mentioned in this thread.
Thanks for the feedback. Looks like another case of faith-based specifications. 
LOL, I had a few typos in my response that I would love to attribute to my occasionally smartphone. “50” is less than 60, THUS, they don’t compare WITH absolute numbers. My thumbs need to catch up with my zest for a good discussion!
Peggy, my experience was very similar.
Wow Peggy. Sounds like an experience I had with a certain fiber based sprayed-on fireproofing material. The firm I was with had an internal memo, not for public consumption, that one of our denser architects sent to the product rep for comment. This, of course, resulted in a very nasty letter from a certain chief counsel to our CEO.
I used to spec their equivalent wet mix products, never the dry mix. Now, for non-public work, I don’t spec them at all. A shame really; some of their reps are good people and some of their products are pretty good as well.
Sounds like there may be other companies out there that need to learn how to play nice. I hate bullies.
But what about the all-important LEED point for reflective roof surfaces? Are you saying that USGBC, the President and Al Gore might not know what they’re talking about? What about needing white roofs EVERYWHERE? I’m aghast! Next you’ll be saying that white roofs only should be used in southern locations where A/C days exceed heating days. What heresy! Our government has made it clear that white roofs should be put on every building everywhere, no matter what.
Better watch out, someone might turn you in to the Green Police.
@Ken - yes, there are definitely others operating in the same mode, much like what Piper just described. I remember the first time I ran into it during the 90s on the east coast on a community college project - the company name starts with a ‘T’ - our roofing consultant wanted to use another roofing system but the lunches and golfing outings provided by the T people overruled the better product. I also remember this lurid episode in SF:
http://schoolroofingscam.blogspot.com/ She’s quite inflammatory but facts are facts. I don’t agree with her reasoning that this is a leftist plot. To me, its simply a greed issue
It’s discouraging.
Re the white roofing/northern climate side issue: The sustainable community has been aware of this issue for many years - it’s called the ‘winter penalty’. It’s the same for solar.
http://www1.eere.energy.gov/buildings/pdfs/cool_roof_fact_sheet.pdf
California has a warm climate, we have done the math and now Title 24 requires a cool roof. Germany is going gangbusters with green roofing, because that works for their climate.
LEED is a menu of potential strategies, and not all strategies can be used on all projects.
Maybe us northerners should use black roofs and apply for innovation credits?
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I think the LEED points make good [if not perfect] sense, because it’s not just degree days. Cooling takes more energy than heating. And for most commercial buildings, internal loads often require cooling even on cool, clear days, when a black roof could just be adding to the load.
Lastly, if DuroLast claims ‘better’ than another product, it needs to prove with test reports. Maybe it is. Claiming quality and proving it are 2 different things. I had a municipal client [in a previous life, a generation ago] that insisted on DL, no equals; since it was the only one factory-fabricated, we could do this. Frankly, I was glad to avoid [most of] any leaking follow-up.
@Peggy: I mentioned the Stanford study not because I had just become aware of the issues with ‘winter penalty’. I was just happy to see something written that echoes what our office has been preaching (without documentation to back it up) for several years.
@Tony: in general cooling does take more energy than heating. However if you are installing a roof on a school that is not occupied in the summer, is north of the mason/dixon line and is not air conditioned then the arguement for a white roof diminishes significantly IMO. Also a black roof would not add much to the cooling load if the roof is well insulated with minimal thermal bridges (there will always be some around penetrations).
Of course it could be argued that in an urban setting a black roof could contribute to the urban heat index. However the Stanford study (and some other studies as well) suggests that greater reflectivity of the roof membrane increased the solar absorption of airborne particles thus increasing atmospheric heating. Of course many of these studies are performed or encouraged by black membrane folks so nothing is definitive but the “white roof” star does not shine as brightly as some would like to proclaim.