My husband and I bought a 260+ old adobe in New Mexico a couple of years ago. It was a great buy but the roof leaks at various places and we have to consider re-roofing the entire building (4,000 sf). Since we moved here from the east coast we have no experience with flat roofs. Most of the building has a flat roof, a newer part has an approx. 10 degree slope. Roll roofing sealed with tar at the seams is on it at present. My husband has already successfully repaired some of the leaks with special tar paper and a torch and he thinks that he might be able to tackle the whole re-roofing chore depending on what method would be best. We heard about foam spray, tar and gravel, brye ?? (don’t know how this is spelled) and variations of these.
Another factor to consider is our 90 pound dalmatian/akida dog who runs on top of the roof and barks at all the neighborhood dogs that try to enter into our 3 courtyards. “It would be psychologically detrimental to his ego if we would deny him this access.” Besides that humans are also frequently walking on it since two parts of the roof are covered by decking.
Considering all these factors what would be the perfect roof cover to use? Please help us decide for or against specific methods.
Replies
At first glance:
Tear off the existing roof down to the deck, install at least 1" polyiso insulation as a roofing base, .060" EPDM, fully adhered, and cover with slip sheet and roof pavers. Typical costs in my area (Central New York) would be about $10-11/sf. About half of that cost would be the pavers.
But:
What is the existing roof deck? Could you screw down a new substrate for the roofing membrane? Keep in mind the screws would completely penetrate any decking material, and be visible from inside. Is the underside of the deck exposed? If you can't screw down, EPDM is not likely the best solution.
Does the roof need additional insulation? an IRMA roof (insulation over the top of the waterproof membrane) might be an option.
How does the roof drain now? Is it dry within 24 hours of a rain? Are the drains internal or over the edge?
What is the roof edge detail? Is there an adobe parapet wall?
Brian
I suggest getting a local architect's advice.
A local roofer might give better advice, though.
For a 360 YO roof out there, on this style construction, I fear that this existing roof could be three or four inches thick from old do-overs layering up. That makes weight a factor.
I would agree that EPDM or possibly a torchdown modified bitumen is the right product.
BTW, I lived inTaos for about eight months once. Wher in NM are you?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
We also live in Taos, more precisely in Talpa. Our house is the oldest adobe in town. The roof is drained through canales.
I can't recall what part of town that is. Northeast?
I was in Questa for about five weeks and then found work and an apartment in the Taos Canyon. I know the constrution style you have.
Urethene foam roofing is not a new thing, just regenerated idea with upgraded formula. It was tried for a spurt in the seventies and fell out of favor. I would not recomend it. UV rays are hard on the stuff. I ove the urethene insulation, but the roofing is not all it is cracked up to be by the pushers.
Having a full surrond parapet wall with the scuppers to drain it does mkae for a challenge, especially for a DIY. The EPDM is probaly easier and better to work with for that, and putting it down over the old is lighter than the torchdown product. If you use the search button here for EPDM, you may find some other good threads discussing it.
Dog traffic is a concern though. Are his toenails clipped?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
I assume that the reason for putting gravel on top of the urethane is to protect it from the vicious UV rays. Dog is running so much that his nails are pretty dull and short but when the other dogs get him going he is running and jumping hard. Talpa is located at the south east end of Taos, parallel to the canyon.
Gravel is not used with urethene roofing. They try to protect it from sunlight UV with paint or other coatings.
A traditional BUR roof is three or four plies of tarpaper and hot asphat with gravel sprinkled into a surface coat of hot tar. I've got the burn scars to show that I've done more than enough of it. if the most reputable roofer in the area recommends that, I would go with it, It is consistant with what you have. The gravel on this is for the purpose of protecting the tarpaper membranes from the UV rayswhich will bake off the volatile oils in the asphalt and leave the roof brittle within ten years, but the gravel surface can extend that life. A smooth surface BUR roof is a potential solution that would require recoating it every five years, but It is not a likely candidate for you with the dog up there. With a gravel surface, it could probably handle him, with your atention to his behaviour, and wear paterns on the roof.
A larger grade of smooth washed river rock is used with EPDM rubber roofs that are not adhered with glue to act as a ballast and keep the wind from blowing it away.
A torch down Modified Bitumen could potentially be done by a DIY with attention to being carefull and it is a tough membrane, but also one that needs a surface caot every five years to protect it from UV
Another problem common with urethene is seals at penetrations like soil stacks and your parapet walls. They would simply broom it down or possibly pressure wash it, and then spray the product on. Good adherance with htis works much like good painting. Most of the work and the final quality is in the invisible prep work.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Wow, that's a lot of information and opinions. Thanks a bunch for taking time to explain in detail. One more question though: Recently I have seen flat roofs covered with a silver coating or membrane which I thought was called "brye". It is supposed to be very expensive but superior in life expectancy. Anybody know anything about this one???
When I looked through the search engines under "EPDM" they mentioned liquid EPDM as the miracle fix. I understand that when y'all (a little southern lingo) talk about EPDM you mean sheets. So what about that liquid stuff?
You sure it wasn't "bur"? (Not "brye".) Or as the last poster said, more correctly, "BUR"--which I would think stands for Built Up Roof. As far as I know, means a roof composed of layers that are torched down, then usually covered with gravel balast.
Dan, I think I found the answer on-line last night when I put "BRI" in the search engine. It's a company's name in the south west that produces the polyurethane foam. Looks like because it's a regional company a lot of people use it here and refer to it as Bri-roofing.
Has anybody used the liquid EPDM? Do you have to remove the old layers of tar roofing before you use it? Van you walk on it?
Has anybody used the liquid EPDM?
I fired off an email to my roofing consultant/estimator, so I may find out what the "industry" opinion is. I seem to remember the liquid application being more suited to small areas (like 8 x 10').
Do you have to remove the old layers of tar roofing before you use it?
My first answer is, "yes very likely." A credible roofer does not like to work over an unknown surface, or an unconfirmed roof structure. Will your roof carry that load? I'm not an engineer, I can't really render a legal opinion. However, the old traditional adobe construction has a lot of redundancy built into it. Which remains true unless somebody compromised that inherent integrity.
Can you walk on it?
For most epdm, you want a slip sheet and a walking surface material. Given your description, flat pavers would be where I'd start from, design wise. That would give the needed protection (for the roof) while allowing dog & people traffic. Back to needing an engineer to know what the roof will carry.
I wish I could wrangle up a site inspection, the weather in Taos right now would make a nice change <g>Occupational hazard of my occupation not being around (sorry Bubba)
I don't know if you are familiar with the style they built the adobes 200 years ago. They put latillas on top of the vigas and then pack dirt mixed with straw on top of it. In our case it looks like 12 to 18 inches of it. 200 years ago that was all there was to protect against the 6 inches or so of rain we get here. Later they just put tar paper on top of it. The dirt is pretty good insulation, we don't think we want to touch this plus it retains the authenticity of the building. Some of our neighbors seem to use the urethane foam method right on top of all the old stuff but it is relatively new and nobody seems to have any experience with it.
Yours is a flat roof of a different breed. The problem as I see it is how to get adhesion between the dirt/straw mix and the new roof. Ballasted is the only way to hold any membrane down to your substrate. That will add 10 pounds per SF, typically.
The urethane foams are not new. They have been around at least 25-30 years. I am an architect who does 3-4 roofing projects a year. I have never used the foam, and the old timers I learned my trade from never used it either. There were stories about birds eating the foam, and it is not well represented in this part of the country. Regardless, I don't think it would hold up under your dog's nails. Once he learned he could scratch it out the roof would be finished.
There are some other fluid applied membranes which could stand up to your dog. Check the products available from Gaco-Western, and try to contact a local rep.
Piffin- The value of the advice you get will depend on which roofer and which architect you talk to. Both professions have their share of incompetents. I know a few architects who couldn't hit a nail on the head, let alone rightfully claim to be a master builder.
Point taken. I know those architects too.
;)
There are Roofers, and shingle layers, and hacks, and hail hounds and more hacks. I wasn't clear when I said roofer that I meant a widely experienced, reputable person who was able to inspect and determine the best material to use in each case before him. To me - that is a roofer. You are new here, so the context of my history here, and the forum of FINE Homebuilding didn't catch up to you yet. Not too many of us recommend hacks. My point was that most archies - in my experience - choose roofing product based on appeance or their own limited past experiences. Roofers however, apply all kinds in all sorts of environments, and know from the callback experience what works and what does not work.
Here's to reinforce your thoughts on the urethene. Most of the guys who sell it are urethene installers and not roofers, by training or background. They got talked into investing large sums in the equiptment on the promise of large and easy profits. Call one of them and they will automatically recommend a full spray job even if a simple flashing repair (that they wouldn't recognize if it jumped up and slapped them in the face) will take care of the leak. They don't make any money on that equipment letting it sit idle while they do simple shingle laying or placing some roll roofing.
This style of adobe construction from that era of history gets roofed over and over again adding weight to the roof structure. all that tar keeps it well adhered and stiff aainst the wind. Where the problem lies is that when it does leak, it is usually at the wall intersect and can often infect the ends of the Vigas there with rot. Somebody who is qualified to know where to look for that and see if they are getting ready to overload the roof on a bad viga shopuld be called in.
If they were to strip the roof down to the adobe, it would need to be recaoted to provide a smooth surface. I doubt that any sort of fasten thru system would work, but once a smooth surface exists, new EPDM could be laid and then ballasted with pavers for a walking surface.
BTW, I would not gaurantee a roof on which a dog is allowed to run at will. I would expect it to fail in some way related to canine behaviour within ten years
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!