| Author |
Message |
Patrick (Unregistered Guest)
Unregistered guest
| | Posted on Wednesday, October 15, 2003 - 04:44 pm: |    |
Has anyone done one of these roofs recently? We have not done this for a long time. We regard this as an old system. Instead we are using a rubberized asphalt membrane with pavers because it is a plaza. We are aware of VOC, odor, fumes concerns. Comments? Reasons to do or not to do? |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 17
Registered: 05-2003
| | Posted on Wednesday, October 15, 2003 - 07:51 pm: | |
For a dead slope roof, coal tar is the only system I spec - check out Koppers web site for info and specs. |
William C. Pegues, FCSI, CCS
Senior Member
Username: wpegues
Post Number: 228
Registered: 10-2002
| | Posted on Wednesday, October 15, 2003 - 09:15 pm: | |
Whether roofing or waterproofing, my preference is hot fluid applied rubberized asphalt. It is one of the systems that is certified by the manufacturers for 0 slope roofs with no difference in their warranty. It is also certified for water impoundment roofs for purposes o f storm water retention.
For VOC or fume trade off, its also one of the few really successful systems that can be configured for 'green' certified garden roofs and has a good history of this in this country and internationally.
For those that don't like, or for reasons of their jurisdiction can't use, a hot asphalt system, the really good quality PVC roof membranes can also do 0 slope, water retention and garden systems...though they can be exposed and custom colored as well. A number of major stadiums and other large span roofs have been done with custom colors or patterns, the new convention center in DC that just opened is 2 custom colors of the roofing, colored to match the metal panel coating color.
William |
Phil Kabza
Senior Member
Username: phil_kabza
Post Number: 26
Registered: 12-2002
| | Posted on Thursday, October 23, 2003 - 09:27 pm: | |
Ever since I got 1st degree burns working in the vicinity of a coal tar cooker in my carpenter days, I've had a decided lack of interest in coal tar pitch roofs, no matter how well they perform.
We've noticed a marked increase in awareness of worker safety issues among contractors in the last couple of years. They are increasingly reluctant to have people working with solvent based materials and other high-VOC materials. I expect the coal tar roof to go the way of the (LaBrea Coal Tar Pit) dinosaurs. |
Joan (Unregistered Guest)
Unregistered guest
| | Posted on Thursday, October 23, 2003 - 10:54 pm: | |
We are diy'ers looking for a waterproofing product to use after we replace water-damaged plywood on our rooftop sundeck. The deck tops an enclosed sunroom and a veranda. There is a metal railing on the perimeter. We live in Virginia where mold is a problem on this shady side of the house. Thanks for suggestions. |
David Axt, AIA, CCS, CSI
Senior Member
Username: david_axt
Post Number: 187
Registered: 03-2002
| | Posted on Friday, October 24, 2003 - 12:36 pm: | |
Here on the West Coast we don't have coal mines like they do in the East. Coal tar roofs are rare. I have never specified one and don't believe I have ever even seen one.
BTW, isn't coal tar a known carcinogen?
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Richard Hird (Unregistered Guest)
Unregistered guest
| | Posted on Friday, October 24, 2003 - 01:39 pm: | |
Joan:
There is no simple answer to your problem. there are so many issues you need to have an Architect look at it.
With regard to other comments I have a coal tar roof on my house that lasted from 1940 until 1998. That is almost 60 years. I overlayed it with a modified bitumen coal tar roof that does not have any of the key self healing aspect of the original. It also has not performed as well. I just could not find someone to do the old fashioned roof on a residential structure.
The carcinogen issue is managable by exercising normal care; covering your exposed skin and smoking your cigrarettes upwind from the fumes.
Also you do not want it on a roof with a traditional 1/4" / ft slope. The coal tar migrates and will plug up drains.
I do not believe it will go away; it is the premium system and many of us know it. I think the biggest problem with the system is that it requires more labor than single plys, and finding good labor is a significant problem. You will not see many firms that will offer it primarily for that reason.
Someday it might qualify for LEEDS points. Someone just has to calculate how many tons of other ripped off roofing materials would be added to land fills in sixty years. |
Sheldon Wolfe
Senior Member
Username: sheldon_wolfe
Post Number: 33
Registered: 01-2003
| | Posted on Friday, October 24, 2003 - 03:23 pm: | |
Worker safety is important, but every job and every product has its dangers. Sure, coal tar is hot, but so are all hot-applied roofs. Should we stop using them because someone might get burned? Working on tall structures or around excavations is also dangerous, but are we going to limit all work to single story, on-grade construction? Heck, driving to work is more dangerous than a lot of things we're supposed to lose sleep over.
That sounds like kidding, but statistics show that the leading causes of injury and death are motor vehicle accidents, followed closely by falls. The roofer has a far greater chance of getting hurt on the way to work, or just by being on the roof, than while installing it.
In the good old days, worker safety was not a big issue; fortunately, we've come a long way since then. The two most important components are and always will be training and thinking. Contractors and manufacturers should be responsible for making sure that workers know how to do their jobs with minimum risk, but workers are also responsible for understanding what they are doing. Beyond that, manufacturers will continue looking for products that are more user-friendly, as any improvement in safety has become an important selling advantage. |
Richard Hird (Unregistered Guest)
Unregistered guest
| | Posted on Thursday, October 30, 2003 - 07:12 pm: | |
I am extremely interested in the future of Coal Tar roofs. I have listed my E-Mail below and would like to run a quick survey of those with a strong feeling.
How many would not specify a coal tar roof under any circumstances?
How many would recommend a coal tar roof, if money was not an issue and it was functionally appropriate, slope, details etc?
If you would also say what State you are from it would be helpful. I guess I am not interested in those that would defer to their client's interest. |
Robert E. Woodburn, RA, CCS, CCCA,CSI
Senior Member
Username: bob_woodburn
Post Number: 26
Registered: 05-2003
| | Posted on Friday, October 31, 2003 - 12:27 pm: | |
I still like coal tar roofing, but hardly ever specify it. I like its advantages, which include its inherent self-healing ability and its inherent water resistance. (Asphalt, with a whole 'nother chemistry, is actually slightly soluble in water, so ponding can be fatal, while ponding isn't a problem at all with pitch.) And, since its non-petroleum-based chemistry withstands attack from oil-based products, it is used, ironically, in and around refineries, where asphalt is produced.
There are pitch roof installations that have been in place over half a century -- I was told in the seventies that the art-deco-era classic, the former Gulf Oil Building, here in Houston, still had its original pitch roof, and I would guess it still has. (It was said to have been sandwiched in between a structural slab and a wearing slab; if so, it's pretty well protected...)
On the other hand, unlike most other roofs, the deck must be dead level (or "pert' near"). So there's no slope, if for some reason you'd ever want to change to something else. (Its melting point is so low, much of it could eventually end up at the bottom of any slope, and even dripping over the edge, if you don't "envelope the felts"...) But it's good, if you need a dead-level roof.
It can melt in the sun (hence, its self-healing); don't try to walk on it, you may find gravel stuck to your shoes. But the fumes were its worst problem. However, better equipment, protective clothing and re-formulation of the pitch itself to significantly-revised ASTM standards, have apparently abated that problem to a currently-acceptable level. (The downside to that is, it's not the same pitch anymore -- not at all the same pitch as the old, time-tested stuff.) It may not be as nasty, but workers still would rather work with almost anything else.
And the felts have changed, too -- we don't use rag felt any more (not to mention asbestos), and when glass felts were substituted, many were found to have sunk to the bottom of the assembly, leaving most of the pitch on top -- not exactly a multi-ply roof anymore, but, in effect, just a thick mass of glass, submerged in a pool of tar. I believe that problem was solved several years ago with a change in the felt. For a while at least, roofs that mixed pitch with asphalt felt (instead of tar-saturated felt) tried to address that problem; I'm not sure how well. I think they're still around.
Then there's the relatively recent development of coal-tar-based modified bitumen roofing, another attempt at the best-of-all-possible-worlds. I don't know how those are doing, but the pitch's modification compromises (or eliminates) one of its best features - self-healing.
And there's the old issue of cost; it's not cheap. How many look beyond 20 years today, and are willing to put their money where their roof is? And having so few manufacturers (only two that I know of) probably doesn't make it the most competitive market...
So, pitch has its strengths and its drawbacks. But you -- most of us -- probably knew all this. Bottom line, IMO: When matched to the right situation (including the right Owner), it's still quite a viable option. |
Rafael C Nelson
Member
Username: rc_nelson
Post Number: 3
Registered: 01-2004
| | Posted on Tuesday, January 20, 2004 - 04:39 pm: | |
I agree with your selection. I specified a coal tar system in 1999. Its main advantage in my project was that the (E) roof structure was almost dead flat, coal tar didn't require costly remedial slopling and alteration to an abutted builing elevation.
I would not specify coal tar in a pedestrian area because of the off-gassing. And I suspect that coal tar, because of its self healing qualities, would not do well under pavers... not sure?
Rafael |
Bob Woodburn RA CSI CCS CCCA
Senior Member
Username: bob_woodburn
Post Number: 33
Registered: 05-2003
| | Posted on Tuesday, February 17, 2004 - 10:55 am: | |
One down, one to go...
Coal tar pitch roofing has been a premium product in a class by itself, with a well-deserved reputation for longevity and leak-free performance due to its uniquely insoluble chemistry, its self-healing nature and its invulnerability to ponding, even on dead-level roofs.
But it may be on its way out as a viable roofing choice.
Honeywell, which a few years ago merged with Allied Signal, one of two US manufacturers of coal tar roofing, has announced it will phase out the operations of its commercial roofing business, ceasing production April 15, 2004.
After that, they say, "...we will continue to sell the material remaining in our inventory, adding, "We will continue to consider warranty applications received by us prior to March 1, 2004." (all emphasis theirs)
As far as I know, that leaves only Koppers as the sole player in the coal tar pitch roofing industry.
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