| Author |
Message |
Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1301
Registered: 07-2002
| | Posted on Tuesday, August 30, 2011 - 05:22 pm: |    |
From the architect:
The contractor wants to substitute the specified Modified Bitumen Asphalt (Garland Versiply 80 SBS) roofing with Johns Manville 4-ply (4GIC-CR) hot asphalt roofing because it provides cost savings to the owner ($36K). The owner's Construction Manager has no objection.
Thoughts pro and con? |
Richard L Matteo, AIA, CSI, CCS
Senior Member
Username: rlmat
Post Number: 440
Registered: 10-2003
| | Posted on Tuesday, August 30, 2011 - 05:43 pm: | |
Lynn - I've had Owners request the same thing, mostly because the GC or CM whispered in their ear. The thought is that there is a cost savings because they don't have to hire a roofing contractor who is certified or approved by the membrane manufacturer. I would still include the pre-install meeting and required inspections by the membrane manufacturer's technical rep, otherwise, you might not get a warranty. |
Wayne Yancey
Senior Member
Username: wayne_yancey
Post Number: 488
Registered: 01-2008
| | Posted on Tuesday, August 30, 2011 - 05:51 pm: | |
Lynn,
I had this same issue in April of this year. Below is my anwer to our PM. The proposed savings was denied.
"Buildings today use lighter-weight structural materials than years ago. The proposed roofing system should have the ability to withstand the increased substrate deflection and substrate movement.
Asphalt is still the best-known waterproofing material. However, it has poor aging characteristics, becomes brittle in cold weather, is fluid in hot weather, and has little resistance to fatigue.
Elastomeric compounds such as SBS substantially improve these properties. SBS rubber is flexible and has the memory to return to original form. The addition of the SBS rubber to asphalt increases the flow characteristics and improves the low-temperature flexibility and fatigue resistance of roofing asphalt.
Components of both Siplast and JM roofing system may be secured with hot asphalt including the air/vapor barrier up to and including the cap sheet. However Siplast recommends at least the cap sheet be secured with cold adhesive or torch-on (as specified) to protect the non-SBS hot asphalt secured base layer from UV.
The hot asphalt used by both Siplast and JM in a traditional BUR to secure base field ply/base flashing layers is a commodity Type III and IV asphalt known commercially at "Trumbull" asphalt. However, when SBS plies are used within a hot applied system, the products are dissimilar. No advantage (other than $) to secure flexible SBS membranes together with the much less flexible Type III and IV asphalt.
Elongation in % is: 10% for Type III asphalt; 5-7% for Type IV asphalt; 1000% for SBS modified.
Cold flexibility is: +40 degrees F for Type III asphalt; +45 degrees F for Type IV asphalt; -15 degrees F for SBS modified.
In summary, SBS modified asphalt features the following properties:
Improved elongation
100% elastic recovery
Low temperature flexibility
Long term aging
Resistance to heat aging
Very high bonding to the substrate or between layers.
Yours for free.
Wayne |
Richard L Matteo, AIA, CSI, CCS
Senior Member
Username: rlmat
Post Number: 441
Registered: 10-2003
| | Posted on Tuesday, August 30, 2011 - 06:51 pm: | |
I have to agree with Wayne.
When I was back East (CT) - the preferred method by architects, roofing consultants, & reputable contractors was 2-ply SBS modified bitumen.
I came to CA and it seems we're back doing 4-ply hot-mopped technology - go figure! |
Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1302
Registered: 07-2002
| | Posted on Wednesday, August 31, 2011 - 09:12 am: | |
Thank you both! I will definitely pass this information along to the PA. I had misgivings, and just couldn't pinpoint why, so I came to the experts and am rewarded. |
Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1303
Registered: 07-2002
| | Posted on Wednesday, August 31, 2011 - 09:29 am: | |
And Richard, odd that you should mention CA - that's where this project is. |
Anne Whitacre, FCSI CCS
Senior Member
Username: awhitacre
Post Number: 1198
Registered: 07-2002
| | Posted on Thursday, September 01, 2011 - 12:24 pm: | |
there seems to be an entrenched batch of people in the California community who will cling to their 4 ply built up roof until they finally stop working. I've had innumberable arguments with architects here (not in my firm, but at CSI meetings) about the idea that "the only roof worth using" is a 4 ply built up with type III/IV asphalt. I finally just stopped engaging in those discussions -- its that old thing about wrestling with a pig: they think its fun, and you both get equally dirty. (and the pig thinks its winning) |
Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1305
Registered: 07-2002
| | Posted on Thursday, September 01, 2011 - 12:34 pm: | |
Anne, Thanks for the good laugh and sage advice. I envisioned a roofing contractor of about 64, gray and balding, with a paunch, who "had always done it that way" and was not willing to ever admit that there just might be another way. |
Wayne Yancey
Senior Member
Username: wayne_yancey
Post Number: 490
Registered: 01-2008
| | Posted on Thursday, September 01, 2011 - 12:39 pm: | |
Carefull Lynn,
I am 64, gray and balding, small paunch but no apron.
However, I am always open to "another way."
Wayne |
Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1306
Registered: 07-2002
| | Posted on Thursday, September 01, 2011 - 12:50 pm: | |
Well, good, I'm glad you're not wearing an apron...or even a napron (y'all can look it up if you're not familiar with the word). Anyway, I think wearing one on your bike would look ridiculous. |
Richard L Matteo, AIA, CSI, CCS
Senior Member
Username: rlmat
Post Number: 442
Registered: 10-2003
| | Posted on Thursday, September 01, 2011 - 12:54 pm: | |
Same here Wayne, but I have to agree with Anne on roofing contractors, or as I mentioned in my earlier post - Owner's who think they can get the roof cheaper by going to 4 ply BUR
Lynn - regarding Garland, I'm not a big fan of them either. On a project with another firm they gave me a difficult time because they wanted me to register in order to get product info and specs on their website. When asked if they could just put the info on a disk, the disc required that I register. I finally told them to send me the info without requiring me to register or don't look for their product in my spec. They also gave me a hard time because I wouldn't put the contact info for their local rep in the spec. This is a policy of mine not to do that because the info can change. |
Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1307
Registered: 07-2002
| | Posted on Thursday, September 01, 2011 - 01:13 pm: | |
I don't remember why Garland became the Basis of Design. (This project went out some time ago and there have been multiple projects since). I don't like them either, for similar reasons, but also because they appear to target Owners who then insist on using them for projects. |
Richard L Matteo, AIA, CSI, CCS
Senior Member
Username: rlmat
Post Number: 443
Registered: 10-2003
| | Posted on Thursday, September 01, 2011 - 01:16 pm: | |
Gee - where have I heard that before!
In my case, they "targeted" my Project Manager.
He took their side, but I won. |
Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1308
Registered: 07-2002
| | Posted on Thursday, September 01, 2011 - 01:21 pm: | |
It's good to know the Good Guys in the White Hats win sometimes...(and yes, Wayne, I see you're wearing a black hat, but you're still one of the good guys) |
Gerard Sanchis
Senior Member
Username: gerard_sanchis
Post Number: 44
Registered: 10-2009
| | Posted on Thursday, September 01, 2011 - 01:45 pm: | |
Lynn,
I understand that there are better roofs than a 4-ply but in our climate - I'm talking about Southern California with average yearly rainfall of 15.11 inches in Los Angeles, and a mild climate (this is not Quebec City and the temperature seldom dips below 40 degree F), a 4-ply roof membrane has and will perform well for 10 to 15 years without much maintenance.
With a regular maintenance program it probably would last another 10 years.
When specifying for projects outside our geographical area, we always require a peer review by a local SCIP member. It avoids many mistakes and saves our clients and their clients time and money.
In your case, I agree with the CM and CM. The 4-ply roof is cost-effective and appropriate. |
Phil Kabza
Senior Member
Username: phil_kabza
Post Number: 483
Registered: 12-2002
| | Posted on Tuesday, September 06, 2011 - 11:06 pm: | |
If you are still evaluating the 4-ply asphalt vs. the SBS system, I suggest you ask questions about the microclimate. Are there high diurnal temperature swings that will expose the roof to high tensile stresses? These are common in high desert environments, or in settings like Charleston or New Orleans where afternoon rains cause sudden roofing temperature drops: it's the temperature swings that tear up the membranes and flashings, and SBS systems tolerate tensile stress better than the conventional BURs. |
Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate
Senior Member
Username: lynn_javoroski
Post Number: 1309
Registered: 07-2002
| | Posted on Wednesday, September 07, 2011 - 10:07 am: | |
Well, I may still be debating the issue in my own mind, but the Owner has spoken and it's a done deal. Gerard, this project is further north in CA, near the SF area, so it's not quite as warm. Phil, I'm not sure about microclimate; the only time I was in SF, it was colder than I wanted, but no where near what it was in WI at the time! |
Steven Bruneel, AIA, CSI-CDT, LEED-AP
Senior Member
Username: redseca2
Post Number: 294
Registered: 12-2006
| | Posted on Wednesday, September 07, 2011 - 12:39 pm: | |
We do a lot of healthcare work, and the most common reason to reject hot asphalt, beyond any performance criteria, is the odor. |
David Axt, AIA, CCS, CSI
Senior Member
Username: david_axt
Post Number: 1244
Registered: 03-2002
| | Posted on Wednesday, September 07, 2011 - 01:41 pm: | |
Steven,
Check out Malarkey Roofing's new "No Odor" asphalt. I went to a live roofing demonstration and although there was no "no odor", there was extremely little odor and the odor only lasted for a brief few seconds. I was pretty impressed. |
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