I just finished a job rebuiding a water-damaged commercial building. The owner is getting estimates from various roofing contractors, and since he’s an old friend, I’ve been helping him deal with this.
Well, there sure are a lot of roofing options these days, and everyone recommends something different- EPDM, torch-down, tar and gravel, cap sheet, foam, this strange thin layer of plastic- the list goes on and on.
Just wondering what would be the best choice for a flat roof, approximately 5000 sq.ft. There is occasional foot traffic on the roof from HVAC maintenance and the guy (me) who sweeps up the leaves that collect up there (many trees around the buiding). This is in an area (Fairfield , CA) where it gets into the 90’s in the summer and the 30’s in the winter, and pretty windy.
Although cost is always a factor, my friend would rather pay more for a high quality, long-lasting roof. Thanks very much for any suggestions.
Steve
Replies
I'd look into a white or grey membrane roof- EPDM or PVC. The light color will reduce the heat absorption of the roof, and the membrane should carry a 15-25 year warranty, depending on the product. Use walkway pads to create paths to and around the HVAC equipment, to avoid damage from the servicepeople.
Here in NJ, the system would cost $7-9/SF, including tearoff, depending on whether the roof steel was pitched (flat insulation) or flat (tapered insulation).
Bob
We are working on a building that got a http://www.duro-last.com roof. I don't know how much it was, but I was told that the owners spec'ed it because it is a very high quality product.
Mark
Yes, I am serious. And don't call me Shirley.
We've used several different systems on the roof of a manufacturing plant I work for. We used a white "rubber" single membrane, I think it's EPDM or Hypalon. It did not hold up well at all. In less than 10 years it got brittle and leaked. One material that we've had really good results with is Siplast. It's an SBR-modified asphalt, I believe. In any case, it's been the most durable and trouble free of the systems we've installed. Most roof leaks occur at flashings. I recommend using the entire system from one manufacturer and following their details exactly.
For commercial use it's hard to beat a better-quality torch-down with a reflective coating.
All torch-down is not created equal. SWEPCO seems pretty good to me so far.
The reflective coating is important for longevity. It will pay for itself in reduced cooling costs.
I would caution anyone against a foam roof. I spent a lot of time fixing commercial roofs in Phoenix. The foam roofs are great until they fail, which they sometimes do, and then they are a nightmare. It's like having a big sponge on the roof that hides the problem until the building is severely damaged by undetected moisture. By the time you see the leak, it may be too late to do much about it.
Owners of commecial space generally can't afford that kind of down time.
The foam installers will tell you all of the benefits, but they probably won't tell you how much birds and rodents like that stuff for nesting material.
DRC
One of my brothers is a civil engineer in charge of all construction projects at a paper mill in South Carolina. They spend over 50 million a year on new construction and maintenance including lots of new roofs each year. He says that after 20 years of trying every new technology roofing out there they have gone back to tried and true built up as the most economical and durable. Seagulls constantly picked holes in the EDPM but he said it dried up in 10 years or less anyway.
I vote for EPDM. I don't understand the reports of drying and cracking. I know that I have heard folks call other material by that name when it is not an EPDM at all. I have torn up the material when it is more than fifteen years old and it behaves just like when put down. If these reports are for EPDM, there must be some sort of combination of UV, climate, and chemical pollution that impacts life expecancy, IMO.
With any roof the quality controls and craftsmanship of the installers are at least as important as the material itself. That makes checking into the reputation of the company highly important. The seams and protrusions are the source of problems, especially with single ply roofs. On torchdowns or BUR roofs, the experience of the crew in maintaining proper temperatures will affect the life of the roof. Too hot and more material crystalizes and the finished product is more brittle because the volatile oils are cooked off. Too cool and the bond between plys is weak.
Not enough tar and blistering happens. Too much and alligatoring opens it up. Yada, yada, yada....
Get good people doing the work.
Excellence is its own reward!
Thanks so much for all the suggestions. Like the governor's recall election out here, it seems there are many possible choices. It would be nice if there was one clearly superior product that everyone agreed on, but maybe that's not going to happen.
One of the contractors I met with was a Duro-Last roofer. He said he'd been roofing for 30 years, and switched over to this product about 10 years ago. He sure made it sound like it's the best product ever developed, but somehow the idea of putting a thin sheet of plastic over everything didn't seem like the way to go. But who knows- maybe it's that good.
I'll keep researching and see what turns up. The comments about getting a quality installer, no matter what material is used, is well-taken. I really appreciate the feedback- thanks again.
Saw Duro-Last used in FL
Didn't fair well. Maybe 3/4 years.
Who ever invented work didn't know how to fish....
Maybe they oughta change the name to Duno-Last then..
Excellence is its own reward!
Google a company called Resource Conservation Technology. They've built an excellent reputation in weatherstripping, and now they have two flat roofing product lines.
-- J.S.
I installed a factory seamed EPDM roof from them. Struck me as excellent, if expensive. 5 yrs old. I've used their EPDM weatherstripping extensively- wonderful, and inexpensive, products.PAHS Designer/Builder- Bury it!
Thanks all for the additional information. It seems like EPDM might have a slight edge from the respondents here, and may be the way to go, but I'll continue looking into this.
THis may help you decide. http://www.facilitymanagement.com/articles/artroof3.html
http://www.benchmark-inc.com/roofinfo/articles/archive001.html
http://www.stevensroofing.com/CompanyLiterature/PDFLiterature/HypalonBro.pdf
I've use Stevens Hypalon with great sucess in the past.
Eric
our condo board junkd the "rubber roofs' and went to a sloped steel / metal roof. too many ifs, buts and maintenance on the "rubber/fabric" roofs
the whole idea of a flat roof fights mother nature.
why the he## do architechs put them in?????
$
Who ever invented work didn't know how to fish....
yeah
rotted wood and termites cost $ too when the flat roofs leak
And then there is the Phenomen of "Ponding", wow, that one has always put a smile on my face, except!! when it literally brings the roof down, and people, either get killed or hurt
There is too much you don't know about flat roofs to be making such broad comments. There is no "fabric" in rubber roofs. Careless installation is by far the biggest reason for thm leaking and that will cause a leak in a pitched roof too.
A flat roof is often the best design for a building. It just needs to be installed right and maintained..
Excellence is its own reward!
I understand about no fabric - that was a figure of speech.
My personal very opinionated opinion is that flat roofs are loved by the flat roof industry because they produce lots of revenue over time to find leaks, fix leaks, and repair the damage underneath. the warrantys are also very fuzzy the closer you look into them. Our condo board after a lot of looking for three buldings thought they "fought mother nature" because :
- flat is bad for water runoff causing pools of water on the roof as the building settles (ask a termite man)
- debris (leaves clogs up drains etc
-putting a thin rubber sheet (roof membrane) out in the sun causes it to fail, compared to thicker stronger metal or asphalt
It really is ridiculous to think that a roofer puts on a flat roof so he can make money fixing leaks. Think about it.
I spent nearly twenty years doing all kinds of roofs, includuding BUR. Other than careless work, the biggest reason for leaks would be builders or homeowners who choose a cheaper version of a good roof. On BUR they go for two ply instead of four ply. On EPDM, they go for the lighter thicknesses. Don't be blaming the design for faulty installations or cheap owners. In most cases, I would take the EPDM roof over a BUR without hesitation. The failure of your product sounds unique, so you should not be blamiung an entire industry.
There are time when a low slope design is picked when a pitched roof could do as well, but there are a great many times when a building would cost twice as much to build with a pitched roof design.
The key to success is to choose both good roofers and good materials. Maybe your board failed in that by bidding out to the lowest bidder..
Excellence is its own reward!
The original roof was installed by the builder not the board.
the boards decision , after a lot of meetings with an experienced arch., was i think based on the "IF" factor of rubber roofs (flat roofs)
- if you choose the right one cause there is always a "new" roof membrane product that solves all the problems but of course is untested
-if the roofer got ALL the seams done right. lotsa seams like a wood boat vs a fiberglass one.
-if a tree limb did not puncture it
- if the sun did not crack it
- if someone did not walk on it and puncture it
-if you had the leaves taken off at the little drains each year or three times a year to avoid giant ponds of water
- if the warranty was any good cause people think the roofing companies keep going out of business
etc.
the metal roof on the three buildings cost cost more but it was perceived that it did not "fight mother nature" in that water would run off easier.
Sorta like the wood siding issue - wood is really great IF
if you get the right kind, if it has no splits, if you paint all 6 sides etc etc. why not just use masonry or hardie plank and avoid the ifs.
I think America uses too much crappy building materials compared to say Europe .
Well, the EPDM was first developed and marketed in Europe for close to twenty years before it was introduced here in America. Manufacturers waited to get the test time out of the way.
The majority of the "IF" factors you mentioned will apply to metal or shingle roofs too, if you stop and think abnout it. The biggest difference is that a leak in a flat roof will generally allow more water into the structure than the same leak in a shingled roof because of the fact that the water is moviong off faster instead oif ponding. But what will often happen with a pitched roof is that it doesn't leak bad enough to bother the residents and require immediate action. So they postpoone it long enough to let the structural and sheathing wood rot.
You have some valid points for sure, but making a blanket statement over all flat roofs is what I objected to.
I still hesitate to believe that your roof was an EPDM. Probably some other similar intro product. I'm not saying that you are wrong, but that someone may have misled you or misused the term. There have been a lot of other sheet membranes introduced in the last fifteen or twenty years. .
Excellence is its own reward!
Keep it simple.
In California, single ply membranes don't dominate the market the way they do in Pennsylvania. A three ply built up system would be an excellent choice where you are because I am sure you could find several reputable contractors to install it. As mentioned before, modified bitumen roofs (torch down) are good products, but the installers must be very careful not to burn the building or burn or underheat the product. The silver coating is also an expensive maintenance issue.
Single ply EPDM is also a great product. You can see more here:
http://www.carlisle-syntec.com/documents/ResLib/EPDM%20Briefolio.pdf
Both 3 ply built up and EPDM when properly installed and maintained can go in excess of 30 years. I have seen the built ups go 40.
The largest cause of premature low slope roof failure I have seen is moisture in an old roof that has been covered by an new one. It is always done to save money and it never pays.
Although cost is always a factor, my friend would rather pay more for a high quality, long-lasting roof.
If your friend really feels this way, make sure they tear off the old roof down to the deck.
carpenter in transition
Edited 9/17/2003 10:37:13 PM ET by TIM_KLINE
Best roof available 4ply Coal tar pitch,if you can find someone that will install it.I would lead you in the direction of a SBS granule surfaced using SBS modified base applied with HOT ASPHALT not a torch,I know there are alot of guys out there that think its the best way to gois torch apllied but the installation is dependent on the installer's eye to tell him if he has done it right.
EDPM and the other one plys, one of the biggest misunderstandings the warranty 10 or 12 years on the installation never 20 or 25,many are prorated (read less value as years pass)and yes they do fix any leaks that occure that are FROM PROBLEMS RELATED TO INSTALLATION,and aword to the wise here I used to run a company that did $350,000 a year in repairs for one manufactor alone
So just because a roof system has become popular dosen't mean its the wave of the future
I would again lead you in the direction of three ply modified roof system and make sure to read the warranty and or talk to the manufactor's rep if possiable all the major players have them and its part of their job
Well, I suppose I've eliminated Duro-Last and foam from the running, so it's down to BUR, modified bitumen, and EPDM (thermoset or thermoplastic?). I'll have to look into coal tar pitch also. This weekend I'm meeting with a builder who's a friend of a friend who's done a lot of work around Travis AFB- should be interesting.
Thanks everyone for the great discussion
The only places I have ever seen pitch used is on larger govt buildings so you might find a contractor around near a govt installation who does it. One that I replaced was a five ply pitch, designed to puddle water for temp control, on a generator buildsing near to a dam. It was nearly forty years old when I tore it up and not in bad shape, except for a couple of cant flashings along the walls. They were replacing it because the schedule said to, not because of any leaks.
In BUR whether with asphalt or pitch, the number of plies is related to the life expectancy. my own expewrience is that it depends on the quality of installation too.
2Ply = ten to fifteen years
3ply = fifteen years or so
4 ply = twenty to twenty five years
5 ply = 30 - 40 yrs.
Excellence is its own reward!