I’m planning to build an adobe house with a flat roof — flat being short-hand for 1/4″ to 1/2″ slope.
I’m getting conflicting opinions as to what kind of roof to put down. Some are recommending a type of polyurethane (e.g., http://www.kykoroofing.com/products/foam.html); others recommend some kind of 3-ply built up roof.
I need a roof that can take our 115 degree temps in the summer and the 300 days of intense sunshine we get here. While it doesn’t rain here often, when it does, it can really pour.
Any recommendations would be appreciated! I’m very confused about this issue.
Thanks — Dan.
Replies
Dan,
Although I am not proud of this, my early years in construction were spent repairing roofs in Phoenix, and I learned a few things about flat roofs.
Here's a few observations based upon experience with repairs of failed low-slope roofs.
1) More slope is better. If you can go as much as 1/12 you'll have a better roof.
2) No foam. No mater what the foamers say, once the birds and rodents get a hold of your roof, it's a heartache. I could go on at length, but let me just say that once they start leaking, which they will, you have an unusually bad problem on your hands.
3) If you go with a tar and gravel built-up-roof (BUR), use a reputable contractor. Often the tar is overheated for the convenience of the crew, and the oils are driven off, shortening the lifespan. Really, there is no reason to go with this material.
4) I would seriously consider a modified bitumen (torch-down) roof. Again, some are better than others. You'll want one formulated for your climate.
5) The single best thing you can do is go with a reflective coating over whatever roof you choose. There are several, use the best you can find. Use a commercial product supplied by a reputable pro roofer. DO NOT go to Home Depot and buy Sno-Coat. It's not the same.
We had many testimonials from plant managers describing how the cost savings in the air conditioning bill more than paid for a reflective coating, likewise for the extended lifespan of the roof.
As a side benefit, reflective roofs help lower the thermal signature of cities, which is something that makes everybody's world a better place.
DRC
I agree with Dave, but you should consider at least one other product, and that is a TPO membrane. It is a single-ply thermoplastic polyolefin which is heat welded on site. It is a great product which draws raves from the installers. In case you haven't seen it, it closely resembles Hypalon and is often called "white rubber". The link below is to Carlisle's site for a technical data sheet on the product.
http://216.239.33.100/search?q=cache:yB7JZp5zFnMC:www.carlisle-syntec.com/pdfs/resource/TBASureWeld_Xtra.pdf+carlisle+sure+weld+roof&hl=en&ie=UTF-8
carpenter in transition
Yes, also a good product with a good track record.
DRC
Dave and Tim,
Thanks for the descriptions of your experience and your opinions. I'll check out these various options and hopefully reach the right conclusion.
-- I don't mind putting on a reflective coating and renewing it every year or two; that is, I don't mind doing annual maintenance on the roof. In contrast, I would hate to deal with leaks. So, I'm hoping to do it right the first time.
In talking with various roofing sales reps, they all have their very strong biases toward their own products -- so you know they aren't objective. So, I'm not sure how to arrive at the 'correct' solution.
I'm almost tempted to put a sloped roof, say 5/12 pitch; but I'm not sure how it would look on an adobe.
Thanks again,
Dan.
Dan,
You can make a pitched roof look great on an adobe. Check out Beverly Spears' book on the subject, probably available from Amazon. If you can't find it I'll get you an ISBN.
As for re-coat, the commercial-quality coatings would only need renewal every 7 or 8 years.
One of the things these coatings do is lower the surface temperature and diminish the effects of UV radiation, so the likelihood of roof failure goes down.
As long as you keep a pitch of at least 1/2 in 12, stay away from the foam, and use a known product applied by a reputable installer you should be fine. There really are a lot of good products. There are also a lot of untrained, underpaid, half-stoned young men with bad attitudes installing them.
If caveat emptor ever applied to building, it's now.
I'd be interested to know how this all ends up for you.
DRC
Thanks.
I searched under "Beverly Spears" at Amazon.com, but the only hit was on ~~Clear thinking, Clear Writing -- not a bad topic but not what we're talking about. More info would be great! We're currently working on our house plans right now, so changes are easy to make on paper.
Dan.
Try Google instead. A search for
beverly spears (roof OR adobe)
kicked up several of her books in the first page of results. With an exact title, it's easier to cruise the various used book search sites.
Think the book you're looking for is American Adobes, subtitled Rural Houses of Northern New Mexico by BeverlEy Spears.
Would also suggest Adobe Houses for Today by Laura and Alex Sanchez. Elegant concept. Pods of rooms that can be added and subtracted based upon need. Various roof and exterior ideas for the same floor plans. They will not modify, but will sell paper and autocad copies for $25 a pop. Play with them to your heart's content.
Why not consider a stucco SIPS house with 8' wide, vertical panels to form parapet walls. Leave the rear walls without parapet and use SIPS 10' panels on a 2-3/12 pitch covered with galvalume metal roofing draining to the rear? I built a house like this near Houston Texas. With the OSB above exposed vigas, you could stain it dark and nail up those sticks (whatchamacallums) real easy. It would look very cool and indigenus. I covered the floor with those sunbaked Mexican tiles,dog prints and all. Actually, I used double 2x4's on the walls and nailed up the windows to the inside set of studs to get the recessed window look. The client wasn't sold on the SIPS concept. More to the point, he was financially challenged. Regardless, the project looked great and they loved the house. BTW, I had a metal cap bent to cover the top of the parapet walls.
Well, I'll tell ya. In Abq, SIPs are uncommon....read expensive. No local mfg and only one contractor that I've found who does installation. As a DIYer, I want to at least see some being installed b4 I tackle it myself.
Rastra and Perform Wall, which I consider the best and most adobe-like ICFs, don't lend themselves to DIY installation because of the weight. Need some kind of crane and if you're slow, increases cost. Also, little margin for error...you better know exactly where everything is going....no changing your mind.
Real adobe has a certain mystique, commands top dollar upon resale and is a very forgiving material. Cheap, labor intensive, and well-suited to the DIYer. Plus, if you get tired, you can hire a zillion guys as day laborers who'll lay them up as long as you watch like a hawk.
I'd love to try SIPs....but I'm not paying an installer a fortune....and I'm not interested in paying freight from El Paso.
Just returned from Houston and Cajun country.....you guys have a whole nuther set of problems. Never saw mildew on an unshaded roof in the middle of a field b4.
Humidity? Well yes, but our skin is so soft. HA! I can understand your admiration of adobe. I love the look and values of that style, and yes, it seemed pricey to me. Way too labor intensive. There's a guy building in Angelfire NM.that is using SIPS. I forget his name. I have been considering building a vacation cabin there and was considering SIPS as a way to contract it myself. A rented crane and an imported artisan crew along with me and maybe a factory rep. could erect the house in one day on an existing deck. I've seen it done. I figure I can frame, side and roof the house in a week or so. For a 1344 sq. ft. house with 8'- 6" walls and 10" roof picked up at the plant,15-16K. 2K for them to ship from Texas. Seems I saw a site for a homebuilder in Albuquerque using panels. There, I did. http://www.sunlighthomes.com Anywho, you asked for ideas and these are some of mine. Hope you enjoyed our neck of the woods. We do. BTW, torch-down is really easy and reasonable.
I've talked to Sunlight. Trouble is they want to design and build while I sit and watch from a distance. Not my style.
Would be interested to hear if you do the Angel Fire thing....and who you come up with to help you. Seem to remember that there's a guy in the Eastern part of the state who will erect the shell only. Clovis? Portales?
ShelleyinNM
The Sunlight group was in response to the statement that you would like to take a gander at one of these things going up. I should have guessed you knew of them. I think they get their panels from OK. Not too far away. Precision Panel is not too far as well, in AZ. I would bring a crew from Houston. I'd have to check out somewhere to rent a rig. Seems I recall seeing one parked in AF last summer. Actually, one of the houses I've watched going up here used an articulated forkift. It worked pretty well. My project is basically a double wide look cabin. 28'x48' 6/12 roof with an interior wet wall. I'd be interested if you knew of a crew that does erections in northern NM.. Like you however, I'm not interested in being held up by some subcontractor. I don't have to put up with it. What size home were you looking at?
Great subject guys...I just moved into a Sante Fe Style home here in SW New Mexico. They put on a 3 ply roof and a "silver coat" for a top coat. A couple of neighbors said to put on a coat or two of Kool Seal ASAP. This stuff is white. Question ??? Can I do it ? Can it be applied with a roller? The local contractor wants appx. a buck a square foot to spray it on.
Well, since I'm here at work goofing off and not so much to do; I'd recommend you maybe check with a roofing supply house in a large city(El Paso) for reflective roofing compounds. Here's one product: http://www.uuaf.us/therma-guard . Sounds like "cool" stuff and has a nice picture of a guy rolling it on. I had a homebuyer that looked at a bunch of insulating paints to possibly spray on the underside of his roof for thermal resistance.(He didn't want to spring for the Kool-Ply) We decided on aluminized paper instead which he installed himself. Anyway, I diverge. That's how I became aware of these products. So, the long answer was, yes, you can roll them on within manufacturer's specs. The point I began to make was look for the best product availabe to you. Some are better than just white elastomeric compounds.
I've never used any of them, but am friendly with a group of engineers who have a home inspection company. They always recommend their usage to homeowners who have a 3-ply tar and gravel roof. Suggest that the gravel be scraped back and it be used on the parapits. They always caution to use the expensive, requires-a-primer brand. They say it can double the life of the roof.
Bill, as far as size, don't know. Around 1800-2000 probably. My mcmansion days are over. Don't know anyone around here except Sunlight...and as I said they're not interested in just erection. What IS popular around here is panelized frame.....especially the tract builders. Lumber Inc in Abq has been doing it for 15 yrs at least.
You might check Trinidad, Colo for erectors. Not that far from Angel Fire, growing, old Victorians being restored....and Colo more into the mainstream than we. BTW, the whatchamacallit stick thingies are latillas...about $4 for a 2" diameter, 6' long. Now that's pricey for a peeled stick.
Anyway, back to the guy in Tucson. Since I'm flapping my jaws, agree with putting more pitch if you decide on a flat roof. If you do the code minimum, the roof will flatten and you'll get ponding....guaranteed. I used the hyperlon, plastic welded stuff on a remodel once. Very satisifed with that. Expensive, tho we were able to use a scrap left over from a commercial job that the supplier had done.
If you use a retail-quality product and apply it yourself you may be highly dissatisfied with the result.
The cheap (buy it at HD or Lowes) stuff tends to fail, but only partially, which is far worse, because you can't go over it and you can't get it to come off.
You don't always get what you pay for, but you never get anything you don't pay for.
DRC
Bill,
In case you're interested. There is now a distributor in Abq for SIPs. Sells the Premier product. Was set up at the Home Builders Assoc show this weekend. Just got started.
David Falco, gen'l mgr, 505-896-4421
Thanks for the 411! I've been "bowed up like a cutt'n worm" for a while now. I've been getting a couple of specs off the ground and bidding a custom. Once they are settled, I'll get to looking at that project up there. What did you do about your project? Going adobe?
The one that I'm starting next month, the one for which I'd investigated SIPs, is for the daughter of a friend. Single girl, first house...so price vs finishing materials is an issue.
So it will be panelized frame. Decided that it would be better to spend the budget elsewhere.
Ah,yeah, I knew that! A senior moment there. Thanks for the 411. My interest in SIPS has to do with the idea I've toyed with for my construction bidness. I have been building customs here part-time for a while and now only build specs for sale. I'm pondering the notion of selling completed shellhomes fabricated from SIPS panels. Considering the price of natural gas, I see a future. We'll see. Chapman Panels in Texas will haul them out there and set them up for you. For a price of course. Nice folks.
I respectfully disagree with the negative comments about foam roofs - I've put several on without problems. Check with Rodney at FPC
Bob,
I'd agree. It's true, there are plenty of foam roofs out there, they can't possibly all be failing, even over time.
It would be interesting and educational to figure out what is the common factor on the ones that did fail.
I don't know what that would be, because I only got called to see the bad ones. I guess part of my attitude toward them is that when they do fail, it's amazingly bad.
I guess it's kinda like the attitude cops get -- they mostly deal with people who have messed up really bad, so they start thinking all people are messed up. <G>
Also, I wanted to thank you. Because of your tone and attitude (respectful and differing) I went back and re-thought my position on these roofs, which I haven't done in a long time.
This all even got me thinking about if more people here came to discussions like you did, instead of just flaming someone they disagree with, we'd probably all learn more.
Anyway, thanks.
DRC
I agree about keeping a respectfull tone.
I'd like to hear about the reason for failures in theesse roofs. It seems to me that the only people who truly love them are the installers/salesmen. They came on big back in the seventies and faded into history just as fast. Now a new generation is discovering them with I wonder what kind of results.
I believe in the foam insulation and the polyurethene products in generall but I've never met a good foam roof or read much about them.
Given that, I have to assume that the installation process is the source of the bad reputation..
Excellence is its own reward!
I don't know what kind of budget you are working with but just in case it is generous, I'd like to share my experience with copper. I had a customer with small roof over his front porch area (about 8x16) that had a very low slope because of the widows walk above. The homeowners wanted something of top quality and extreme durability. I didn't feel comfortable putting a standing seam roof on at the existing pitch (about 1/2" per foot). I put a flat seam soldered seam copper roof on it. That should be good for around one to two hundred years. It was bid to me as low as $6,800.00 but I bought the materials for about $650.00 and my apprentice and I did it in four days. It would be a lot easier now that I am experienced at it. A good wooden mallet, a good flux, a nice metal brake, and a propane torch that has the nozzle mounted on a hose (rather than on the tank) were the key pieces of equipment.
I'd echo what Dave said about the slope - More is better.
I know my experiences with flat roofs are different, being from the midwest. But those experiences have made me awfully gunshy about them. We sure do a lot of quotes and jobs for putting pitched roofs on top of leaking flat roofs.
Duuring my teenage years, I once had the job of cleaning off balasted flat roofs that were leaking, and then re-sealing them. (Don't remember what we used) The roofs were dead flat, and the drains were 2" above the roof surface. And no emergency overflow drains in the 3' tall side walls. Didn't take long for them to leak. Got paid a whopping $3 an hour to do it, too.
Don't know if I'm really trying to make a point - Just suggesting that you be leery of them, or make dang sure they're done right.
STRESSED is just DESSERTS spelled backward.
Boss, If you got $3/hr as a teenager, you are a whole bunch younger than me!
I disagree with the concept, but the idea behind that type of dead flat roof with ponding is that the water lowers the heating/cooling costs of the building.
BTW, I often see people here get stressed over "flat" roofs and pointing out that the minimum normal pitch of 1/4" per foot is not flat.
In roofing terminology, the definition of a flat roof is anything with a pitch of less than 2/12.
Excellence is its own reward!
I have and still do flat roofs... built up and torch down.... for me torch down wins everytime.. and it's something you can do yourself... with a dragon wagon i can do a sq in less than 20 min... (wide open space) plus it's a known... with built up you can have an idea but you don't know true coverage... even just with material cost I come out better with torch down... i have gone to an 18" wide cant at all parapet walls that don't have drains... i do these last and for the last few years i haven't had leaks... I don't use coatings but i sure would like to find one (white) that i believed would hold up and stay on... and... i walk the roof after the first rain and look for any water standing... i happen to like zero standing water... with torch down i can build up low spots pretty fast...
pony
I'd agree with Pony. That dragonwagon can pay for itself on the first job if it's good-sized. It lays down material as fast a two people can move.
Likewise on the cants.
As for reflective coatings, I'd check with the roofing material manufacturers. I think there are some pretty good acylics available. I'm using aluminized now. Not quite as much reflectivity, but reliable. The best white coating I ever used was Permalume's EC500, but that material is no longer available.
DRC
Can you give me any ideas for building up the low spots? What's the best way that you have found?
Thanks,
DRC
fix'n low spots... good roofing supply houses have what i call tapper board... it's usually 2' x 4' and 3/4 thick on one edge and tappers to zero... you can get it 1 1/2" tapper to 3/4" with both you can fill a low spot thats 1 1/2" low... then just cover with torch down... for shallow low spots I'll use 2-3 layers of torch down... around here a 1 sq roll costs about $35 i use it for everything... under sleepers... pathways on the roof between equipment.... as a pad for equipment... ect... I've seen dragon wagons on ebay that never got a bid... but get a good hand torch with the ignitor and the flame control...
$3 per hour! I remember being excited because the minimum wage went up to $1.60! Those really were different times.It doesn't matter how fast you get there, it just matters that you go in the right direction.
OK, yet another vote for more slope, especially because:
> While it doesn't rain here often, when it does, it can really pour.
The weight of the water on a low slope when that happens can actually change the slope by deflecting the roof down. That's what happened to the Kemper Arena. If you have a parapet wall around this, be sure to provide big scuppers and even some overflow scuppers to let that big water load get down off the roof fast. The good thing about parapets is that they hide the roof from view, so you can do what you want with the slope. What you want is as much slope as you can hide with the parapet, 1 in 12 or more.
-- J.S.