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Folks,
I’ve got a flat-roofed home that needs to be re roofed. Due to
various headaches I’ve had in the past, I just want the darn thing
done right. Although I’m not Bill Gates, I’d pay a little extra just
to put this business behind me. I’ve always heard that a single-ply
membrane is the best way to go. When I brought in a woofer that I’ve
always trusted 100% in the past, he said that the single-ply had its
own set of problems and strongly suggested a fiber-glass and gravel
roof. Based on past experience, I’m one that looks to find a good
contractor and trust him, but this seems to go against everything else
I’ve heard.
What is the best flat roofing method for the money?
Thanks.
tom
Replies
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T:
I am not a roofer,but have lived w/ flat roofs in various parts of the country...Bottom line;if you live in a snowbelt,the best flat roof is no flat roof,period!I know,Iknow-"if installed properly a fiberglass/gravel roof..."-maybe fine for commercial structures,not residential.If you're willing to "pay extra to get this business behind"-frame a pitched roof!
This is from too much rooftop shoveling/too many overflowing buckets on the floor experience.
Best of luck.
*Only flat roof to get is an EPDM roof -- I've installed 4 on houses I own on the flat roof additions and have never had a problem. The stuff comes in 20 foot widths so you may be able to get by with only one seam. Pay the extra and you won't be disappointed and it will come back to you when you sell.all the best
*tom,EPDM is my flat roof material of choice, you need to get a qualified installer(someone who is certified by the mfr.) Proper drainage is critical(get rid of those ponds!)- if you don't have it, invest in a tapered insulation system.Don't forget that the membrane is only one component of your roof. Flashing details, scuppers, drains protrusions, roof-top equip., all must be properly handled to insure a functional job that will give you a minimum amount of trouble over the long haul.My favorite solution is to truss and shingle a flat roof, its major drawback is cost.John
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I am not a roofer, but here is my experience. My parent's house with a pitch of about 2 inches per 1 foot, maybe less. The original roof was builtup tar and gravel (excellent workmanship) which lasted about 35 years without trouble. This is tried and true method but it costs. Regular single ply, no matter the quality, may last 5 to 7 years. I redid the roof with something called modified bitumen roll roofing which uses glass sheet base and accompanying roll roofing which can be cold-adhered or torched down. This, about 4 years now, still looks good and no trouble. You do seem to be concerned about price and this system may suit you. The best modern system seem to be the EPDM, which I think is rubber sheet, but it, I think, may be as costly as tar/gravel. I don't know the history of EPDM, that is, its life, UV resistance, etc. I heard some other material other than straight rubber being described as EPDM, but I would be critical of these, unless someone can describe these in more detail. Sorry that I can't be more definitive. I chose the material I used for the handling (weight, no torch), price (as compared to tar/gravel or rubber) and roof supplier's recommendations. Good luck.
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There is only one product that goes by the name EPDM. There are several manufacturers but EPDM (ethylene propylene diene monomer) defines the chemical makeup. I've been told that it has an expected life of 30 years.
*Sorry to go against the grain but I professionally gave up using EPDM after Gates Roofing went bankrupt due to seam failures in the 1980's. My very, very firm opinion on this is DON'T EVER USE EPDM. We just removed a 10-year old Carlisle EPDM roof from a flat-roofed house here in Princeton and most of the seams had failed. When my client bought the house in 1993 he was told the 3-year old roof was guaranteed for 30 years (must be the same guy you talked to, Ryan).Of course, none of the single-ply manufacturers guarantee residential roofs. I also don't like ballasted roofs since the stone makes it very difficult to locate leaks.I do agree on the 'anything but a flat roof' comments (what happens is that roofs set flat deflect structurally and pond), and suggest that you consider the following:(1) Complete tear-off and inspection of the substrate. I assume the reason you are re-roofing is leaks, so you need to know if there has been damage.(2) Installation of tapered roof insulation to guarantee a positive pitch of at least 1/4" per foot. You'll be pitching to the roof edges so you may need to add gutters, etc. A local supplier ususally can work out a tapered shop drawing for you if you give them the roof shape.(3) Re-roof with an APP Modified Bitumen system (torch-down) with a qualified roofer. GAF has a good system - this really ends up as a two-ply roof.I assume that you have batt insulation in the ceiling already - you may want to check to see if it has a vapor barrier. If not, you should repaint your ceilings with a paint that qualifies as a vapor-barrier. One of the problems that can be created when adding board insulation over batts is that you can encourage dew point to occur in the batts rather than higher up in the roof assembly. If you have some reasonable air volume above the batts it's not usually a problem. Unfortunately, I don't know of anyone making tapered recovery board, which would be the best since the added R-value would be minimal.BTW, if anyone out there has a great, flat EPDM roof over 10 years old, please post your good news here!Jeff Clarke
*of course, i agree with everything , and every one of the above posts......i like rubber in its place, fully adhesed, on a good substrate, like 1/2" hardboard that has been mechanically secured with plates and deck screws..then a 65 mil rubber, with appropriate uncured rubber and termination strip in the needed locations...the big draw back of rubber (EPDM) is that it is UGLY, and if it is part of the street scape, then we would avoid it like the plague...also if teh owner has to look out over it say from a second floor window, think about something else...we like the modified bitumens, but we don't do torch downs.. we have done some of the mastic applications, but they can be labor intensive...two of the products we like are Colphene, by Soprema, which is a peel and stick granular surface modified bitumen... we usually lay a new plywood substrate, and apply a primer, and then the Colphene...i think it only comes in a Frost color..the other product is called Low-Slope by Monsey, this is the same type as the Colphene, and comes in dopuble and single coverage, and it is in Frost, Black , and Cedar...this one we also use the primer before the application...many of the cut up roofs will use all three type of roofing materials, 3-tab shingles on the high pitch, peel and stick bitumen on the low slope visible areas, and EPDM in the hidden valleys and trouble areas...
*Jeff,I couldn't disagree with you more. As someone who has installed almost every type of flat roof, I strongly feel that EPDM is just about the best-the only exception being a properly installed hot mopped, pitch(coal tar) roof. But that stuff is so nasty to work with, you couldn't pay me enough to put one on.You gave up on EPDM when Gates Roofing went belly up? Did you give up on the internal combustion engine when AMC went belly up? Did you know that Koppers left thousands of building owners in the lurch when their 1st generation torch down product, KMM, failed on virtualy every roof it was installed in the 80's? I was lucky, I only had it installed on a few porches and porticos, so I was able to eat it and keep my customers happy. I also got burned by GAF (no pun intended) on thiry two squares of their torch down system. The rep inspected the job, admitted to the defect and then got overturned by corporate. I also ate that one. (mid 80's again!)My first EPDM job was 1983, a 35 sq. Proco plate-bonded, .045" system, that is still going strong today. I've been back twice for inspections and minor maintainance work (under $150.00 each). I've installed a couple thousand squares since. New construction, tear-offs and overlays and I've had very few problems-all minor and no major ones. I will say that I haven't and will probably never install a ballasted EPDM system-they are a b**ch to trouble shoot and service.I still do a limited amount of torch down work, mostly repairs, and I don't use torches on residential work or primarily wooden structures. There have been a number of high profile fires over the years involving roof torches, and personally I think insurance companies are crazy for covering this installation system.So Jeff there are thousands of great EPDM roofs out there, but as with all systems, it is only as good as the skill level of the installer.John
*Carlisle ,83 still no leaks . Mike ,I have to disagree with you I would rather look at a plain rubber roof than watch the 90# deteriate. maybe some of the other roofing systems that you mentioned will last as long as the EDPM.
*yur AGREEIN with me Don, not disagreeing...none of the systems i listed are 90 #, all of the granular roofing systems , the Colphene, and the Low-slope are both modified bitumen... i haven't used 90# (single or double-coverage ) in ten years... never liked it before.. then when they took the asbestos out of it , it just became a worthless roofing product with a short life span...
*Mike -- I have 4 EPDM roofs that are still like new after 15 years. The best one is the one on a 19 foot wide roof that I covered with a 20 ft wide piece of EPDM ------ no seams and the roof is what you call flat-flat. Key is the prep of the base the membrane rests on and is attached to with their mastic and secondly the way the roof wraps around the edges and dumps water into the gutters -- it's got to be a system.I have not put down 1,000's of squares but these EPDM's are the best in my opinion -- the look distracts but you have the comfort of knowing it won't leak. What do you want beauty and leaks eventually or somethingg that looks so-so and does not leak? Fourtnately, because of the location and the fact that the roofs are flat you cannot see them.
*If the roof is pitched any, I've used a product called Seal-O-Flex on several jobs and on my own roof. Supposedly developed by the Air Force for hangers (lots of expansion and contraction). I sort of think of it as gore-tex - vapor thru, not liquid water.3/4 " CDX, mop on a layer of acrylic saturant. Roll on layer of polyester felt. Roll on more pink goop. Let dry. Coat with colored UV-protectant layer (recoat every 5-yrs) No leaks.
*The Air Force uses PINK roofing? I don't believe it.Jeff
*HEY !!! I want somma dat stuff. Sounds better'n Snow Roof.
*Snow joke!
*No, I gave up on EPDM when Gates went belly up leaving several of my clients with leaking seams and thousands of dollars worth of damage. It was more like someone giving up on Chryslers after experiencing a Chrysler transmission.
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Have any of you tried Hydro-Stop? It is a great product, available in several colors, and you can
get a finish coat that is suitable for traffic areas
such as roof top sun decks.
*I installed my third EPDM roof about two years ago, this time on a deck sheltering the walk-out basement below. I'd done the deck-on-sleepers thing before, but the splinters from turning while sunbathing were a total nuisance. This time, I protected the EPDM with a short nap indoor/outdoor carpet in a nice corporate grey that i'm sure adds curb appeal. Although i won't be barbequeing on it, it's not leaked so far, although it does give a nasty rug burn...
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splinter,
That's interesting. One of the points I understand about EPDM is that it should not be used in any situation where puddles remain for more than 24 hours. I am not sure why this is. I would think that the carpet might stay wet longer than the EPDM would stay uncovered. I wonder if this might have the same long term effect. For that matter, when you lay down the PT sleepers sometimes suggested, doesn't that give the EPDM an opportunity to remain wet (under the sleeper) for an extended period.
Comments anyone?
Rich Beckman
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Rick, EPDM is used for pond liners, same material on the roof as for ponds. Your information must be incorrect.
We install all of the above types of flat roofs. (commercial flat roof contractor) EPDM, PVC, built-up asphalt, all have their applications and have advantages and disadvantages.
Biggest advantage of EPDM is inexpensive to close in a large industrial building very quickly. (100,000 sq.ft. in less two weeks) and provide a good roof.
As for your roof Tom, you don't give a lot of information to give you an accurate reccomendation, i.e. what is the problem with the current roof, what is the general configuration of your roof, lots of penetrations, skylights etc, multi-level, good access to the side of the building or not etc.
I personally reccomend 4 ply fiberglass felts whenever it is practical to install, (house or commercial) as long as the access is good. If not then usually EPDM when materials have to be carried around the back of the house for example, too far to carry hot asphalt.
If you have any more questions I would be happy to expand on any of the flat roofing systems. By the way, we also install shingles on residential, so I am not totally biased to flat roofs.
*By the way, I get a kick out of the messages that start "I'm not a roofer but the best roof to install is....."I'm not an electrician and I don't pretend to give advice on how to wire your house. If you are not a roofer then don't pretend to be an expert.The advise from LRZ and Kwan is out to lunch. Period. Any material installed improperly will not perform as it is intended. Flat roofs, shingles, drywall, flooring etc. all will fail if not installed by someone trained specifcally for that product. i.e. 1/2" drywall on trusses 24" o.c. will sag, or so I'm told in another thread, but I'm not a drywaller.
*Scott, Thanks for your reply. A specifics of my situation are that it's condensation problem combined with poor previous roofing work. It is a single level residental roof with about a half a dozen penetrations for vents etc (no sky lights). The roof is drained about 5 scuppers. The details are that I have eve vents all around the home but in a small (~12'X 8') section, the vents are blocked by header one end and a chimney on the other. In other words, it gets no ventilation at all. To make matters worse, there originally were two eye-ball ceiling lights in this section, which let plenty of warm moist air into this area. Over the 30 years the home has been around, the plywood under the roof are sagged with the moisture. So now, in the winter, the moisture goes up thru my ceiling and plywood and pools UNDER the roofing material where it freeze. As spring comes, this ice melts and drips down. I have thought about trying to seal the ceilingagainst moisture by plugging every little hole withfoam and painting it with a moisture blocking paint. The problem is that I don't really think I can block it 100%. I mean, a condensation leak that drops one cup of water per season is just as bad as one that drops a quart, right? A contractor I trust has a plan to vent the area but it would require cutting thru the existing roof. He feels the plywood is so rotted and the previous roof repairs so suspect that cutting thru the roof could cause more problems that it fixes. He suggests a reroof at the same time. By the way, I had also heard from a architect that a EPDM roof should only be applied a roof that had some slight drainage slope to it. That's an interesting point about using it to line ponds. That doesn't add up?
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tom,
It is best for ANY flat roof material to have drainage. But that doesn't mean that evryone with a flat roof problem has the bucks to pony up for a tapered insulation system. Tell us how bad your ponding is. How deep and how wide are your ponds? Do they stay there year 'round or do they evaporate after two days? There are puddles and there are swimming pools, where in that spectrum does your roof fall?
If your architect is anything like Jeff the Architect, who posted above, I wouldn't waste my time talking to him about roofing anyway. As a wise man once told me, Architects know a little bit about everything, Engineers know everything about a little bit, and Contractors who have to deal with both end up knowing nothing about anything.
John
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Tom,
If you have a condensation problem that has rotted the plywood to the point of sagging, then by all means you should be replacing the roof and rotted plywood underneath before you do even more serious damage to joists etc. We have run into this type of problem a couple of times in the past, 1 house another 3 storey apt. Way too much humidity, poor vapour retarder (or none) and poor or no ventilation between the insulation and plywood.
Solutions?? You mention perhaps trying to seal the ceiling, I would say a good idea since this seems to be the source of your problems, but not always practical and/or difficult. Venting the roof space is possible with vents through the roof but you will need them in every joist space as the plywood is most likely tight to the top of the joists. (as apposed to cross strapping the joists to allow cross venting) Or maybe add a couple in the bad areas, try to vent the soffit and also try to reduce the amount of humidity in the house, exhaust fans, reduce humidifier settings etc.
When we replaced the problem roofs we added vents directly over the problem area (bathroom) and reccomended the owner add continuous soffit ventilation.
Of course any dead flat roof is not good. Most all new buildings are constructed with a positive structural slope to the drains, typically 2% or 1/4" per foot. Adding tapered insulation is expensive, more than most homeowners are willing to pay. Quite often what we will do on houses with ponding problems is add some additional fibreboard insulation to build up the ponding area, as long as the pond isn't too large. Doesn't eliminate ponding but is less expensive and does work to some degree.
Scott.
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How deep are your ponds? You must be kidding, right? Drainage is 'best' but not mandatory? For warranty purposes in commercial work, roofing companies require pitch to drain, usually 1/4" per foot. To allow for less in residential work, even though no warranty, or especially because of no warranty, is crazy. Structures that start off level deflect under load, usually to center and allow for ponding to occur. Tapered systems at least guarantee the pitch if the structure itself isn't pitched. As you said in your first post, 'invest in a tapered system.'
The rest of your post is pure insult and doesn't deserve a reply, except to say that I wouldn't insult you for no reason.
*Tom - The specifics that you add match my clients house to a 'tee' right down to the eyeball fixtures. In his case many of the perimeter vents were clogged with multiple coats of paint. We also thought that there might be a serious condensation problem, but when the EPDM was ripped off it turned out that it was almost entirely seam leaking (according to the roofer), not condensation that caused all of the leaks. The re-roof with tapered iso + APP mod. bit. has fixed everything, including the 'condensation problem.'
*How about painting the ceilings with one of the vapor-barrier rated paints (1 perm or less) putting the barrier in the right place, along with sealing any penetrations like recessed lighting, etc.
*Once upon a time, someone would have posted:Repair the damage and fill the roof space with dense pack cellulose. Or at least a variation on that theme.Rich Beckman
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Jeff, good idea. How would you seal around the potlights?
Sorry Rick, I don't follow your suggestion.
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Unfortunately, you can't. If they seem like they would be the 'weak' point in the system he would either have to live with them, see if the eyeball trim can be replaced with lensed trim (probably not) or eliminate them ($$$). I can't remember if IC housings (for direct contact with insulation) might have more effective continuous housing than some recessed fixtures. Even so, replacing housings is a real pain unless they are of the remodel type. Of course it's only 2 fixtures.
*Jeff,You didn't insult me, I shouldn't have insulted you. My apologies to you..... my comment on architects and engineers is an old saw that even my father(an engineer) and my cousin(an architect) find humorous.I must say however, that you posted a comment condemning EPDM roofs because 1 mfr. went out of business. There are dozens of mfrs. out there that haven't, and you give up on the whole industry. My automotive analogy stands-that's an absurd reaction.Should a flat roof be built without pitch? Of course not-that also is absurd. But in the reroofing world, I deal with roofs as they exist, and building owners with budgets they can afford. All jobs don't get specked by an architect, and all building owners don't have deep pockets. A tapered insulation system can double the cost of some roof jobs. "Ponding water" is a subjective statement-some is minor and some is major, to the point of being a safety hazard. It is not unreasonable to ask for clarification on how much is ponding. While it is desirable to eliminate ponding, not all ponding NEEDS to be eliminated to have a perfectly functional roof. On the majority of flat roofs that I do, the building owners opt not to pay the extra money that the mfrs. demand for a warranted system. They settle for the material defect warranty that comes with no extra charge and my 5 to 10 yr. workmanship warranty.I still say, if you need advice on a roof job, don't ask an architect,ask an established and competent roofing contractor.John
*SCOTT: I notice you've failed to address the actual post here...Sharing personal experience in similar situations is acceptable,not contemptible-as you seem to indicate. Methinks you doth protest too much.
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I know nothing about EPDM and how it compares to other roofing materials. The only flat roofing I ever do is with 2-ply modified bitumen. I did a roofing job about twelve years ago with something from the Soprema line which might be interesting. The roof went on a work of the stupidest imaginable structural design which resulted in water ponding against a wall. We couldn't do anything about the slope for any sum of money that customer could afford, and the house wasn't worth the kind of money the slope fix would have cost. Still, she wanted the leaking fixed so we torched on the Sopraflam roofing. It has has been sitting there for twelve years now with 1 1/2" of water on top of it and no leaks. Sure, the proper thing would have been to fix the original problem causing the reversed slope, but when we presented her with the choice between structural corrections and food on the table she wimped out.
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Folks,
I've got a flat-roofed home that needs to be re roofed. Due to
various headaches I've had in the past, I just want the darn thing
done right. Although I'm not Bill Gates, I'd pay a little extra just
to put this business behind me. I've always heard that a single-ply
membrane is the best way to go. When I brought in a woofer that I've
always trusted 100% in the past, he said that the single-ply had its
own set of problems and strongly suggested a fiber-glass and gravel
roof. Based on past experience, I'm one that looks to find a good
contractor and trust him, but this seems to go against everything else
I've heard.
What is the best flat roofing method for the money?
Thanks.
tom
EPDM single-ply rubber roofing membrane has been an appealing choice of the residential and commercial roofing industry for over 40 years. It is the number one roofing choice of architects, roof consultants and contractors for both new construction and roof replacement projects. Nothing better complements the flat roof than EPDM membrane coated with Liquid Rubber for added protection.