Hello — I need some insights about adobe building.
We just sold our house; have purchase a building lot near Apache Junction, AZ. We have lived in the desert (Phoenix area) since the late 1980s.
We have been wanting to build an adobe house for years, and now is our chance!
I was set on adobe bricks (16″ wide, from Old Pueblo Adobe in Tucson (see their website)), but recently talked with somebody who was a fervent advocate of rammed earth (purported benefits: thicker walls=more mass; you handle the dirt fewer times vs. adobe bricks).
So, I’m wondering if there are any adobe/rammed experts out there willing to share their opinions. Q: What, in your opinion, are the pros and cons of adobe bricks versus rammed earth?
Another Q: Since we are just in the design stages (doing much of it ourselves, for a ~2,200 square foot house), what would you suggest regarding a flat roof (1/2″ pitch) versus a pitched roof?
Q: Is there anything else to think about at this early stage (other than changing our mind about adobe!)? Right now is frustrating yet free stage — everything is on paper, so changes are easily made.
Thanks! Dan.
Replies
DanK,
Perhaps you've read the book, THE RAMMED EARTH HOUSE, by David Easton
This is a very insightful book. Anyway, according to the book, and I quote:
"David Easton is the founder, along with Cynthia Wright, of Rammed Earth Works (REW Associates), a company that over the past 20 years has designed and built more than 100 rammed earth structures for residential and commercial clients around the world. They live in Napa, California."
Perhaps you can contact these folks...they appear to be experts in the field. BTW, After reading this book, I would love to build one of these...LOL on your dream home.
Davo
Well, Dan...I don't really think there's much difference. You didn't say whether you're going to DIY. Rammed earth has never really caught on around here, tho there's one guy who does it. Rammed earth not DIY, adobe is. You can hire guys who will lay it for so much a block or DIY; not so with rammed earth. Rammed earth is smooth, exposed adobe gives some texture. Uncovered rammed earth is kinda ugly, adobe is not. Rammed earth is fast, adobe is not. Rammed earth lends itself to square hard edges (modern design), adobe can be a soft, rounded form (traditional).
If you're hiring a GC, I'd go with price....if the look that you want can be accomplished with either one.
Want thicker walls? Lay them the long way or build a double wall. Depends upon how deep your pockets are. Design as many interior dirt walls as you can. More mass. RIF heat. If you're doing wood ceilings, be careful of light. Thick walls and dark ceilings can make them darker than you think. The books don't tell you that. Still, long fairly narrow windows are traditional. It's a balance thing. Check the house in the lastest home issue of FHB's Houses 2003. Bright sunshine outside, kitchen is dark even with the lights on and a bay window.
If you choose adobe, lay it up with mud, not cement. Lay no more than four courses a day. Delay stucco as long as you can. Lot of GCs don't want to fool with that.
I see Old Pueblo's ads all the time. Strikes me as an upscale, yuppified place, tho I've never been there. Have you checked prices? The Yaquis have an adobe yard. Have you checked Nogales? Douglas? If you're going to plaster inside and out, have you checked out Rastra or Perform Wall? Also fast. Gives the traditional look. There's some guys in Pima with a factory. Used to work for Rastra. Must have changed it in some way to avoid a lawsuit, but it looks the same to me.
A flat roof is always going to be more trouble than pitched. Then there's the fact that you'll not have access to whatever's up there. But pitched is not very traditional in the low desert. I'd design a serious parapet wall and pitch it as much as you can. Ponding is trouble.
ShelleyinNM
I found this site on the JLC web site. Try it.
http://WWW.thecorralesadobehome.com/Site_Menu.html
Dan,
It depends upon what you want to end up with. My experience says walls less than about 2' thick, adobe costs less. More than about 2' thick, you're probably better off with rammed earth.
As for thermal mass, don't bother with the difference. Look up the specific heat of dirt in BTU per cubic foot, check the U value, look at the solar gain in BTU per hour per square foot, match that with the degree days in your climate, and you'll soon realize that the arithmetic doesn't support a lot of extra design effort on your part.
In every case, with no exception a pitched roof is going to work better, last longer, and provide you with a more comforatable and durable home. The only two reasons for a flat roof are style and saving money in the short run.
Build whatever you want, get the overhangs and glazing right for shading in the summer and heat in the winter, get the solar orientation right, and have fun.
Rammed earth is not cheap. Anybody who says otherwise is letting their philosophy get ahead of their common sense.
You're going to pay, either in cash, or in time and sweat. If you're OK with that, then you can have a really great project.
DRC
Thanks for your all comments!
All along we have been focused on adobe bricks (as opposed to rammed earth) -- but we were temporarily detoured by the idea of rammed earth. We like the look of exposed adobe bricks better, and we think it's going to be cheaper because we will leave the walls exposed inside and out (except for a few inside, where we stucco or just paint off-white to distribute some light around the interior).
-- Since we are on a tight budget, I want to do some of the work myself, so we've taken an adobe laying class from Joe Tibbets in Bosque Farms, NM. And, in a previous life, I was a mason, so I know I can do some of this myself (but am under no illusions that i can do it all myself). Perhaps, I'll try to GC the project, as I've arranged my work schedule to have a lot of time off during Dec 03-Aug 04.
I don't need any convincing about solar orientation -- here in the desert we primarily need to keep the sun out. Thus, we will keep the long axis of the house on an east to west axis and keep the western windows, especially, to a minimum (which suits our lot perfectly). -- We have fantastic views due north, so will have a number of windows facing there and also great views to the east-southeast, so we will put windows there with patio and overhangs/patio roof.
I'm still very torn on the flat roof vs. pitched. Certainly, if we were at higher elevations with freezing and thawing it would be an easy decision -- pitched. However, in the desert, we don't get snow, etc and we like the pueblo look. -- Plus, we were planning, at least in a couple of rooms, to put in vigas and latillas, and I suppose you can do that and cap it with a pitched roof, but . . . ! Another approach would be to put in exposed trusses, but i'm not sure how that would look with the exposed adobe walls. Anyway -- this is part of the fun I suppose. Perhaps I'll take Shelley's advice and put up significant parapets and try for more pitch, e.g., 1/12.
I am definitely concerned about a dark interior, but I hope we can negate that with some "solar tubes" positioned above a light-colored/stucco wall for reflection off the wall.
Old Pueblo Adobe's adobes are the best quality adobes I've seen. One of the huge cost drivers is shipping and OPA is about 80+ miles from here. I have a friend who is building an adobe nearby; he says the transportation costs almost double the cost of the adobes, especially with gas prices of late.
Most of the adobe people that I've talked to in this valley, use the regular adobe mix(same as in the bricks), throw in the asphalt emulsifier, and then one sack of cement for the mortar. The cement lightens the mortar up a bit, but not too much. The upside is that more than 4 courses a day can be laid up. -- Also, it makes the joints more durable, since they are already the weak part of the wall.
Thanks again for all the comments. Any followups would be appreciated!
Dan
If you're stuck on a flat roof, then build one. I don't think a traditional adobe would look right with a pitched roof anyway. I don't live in a desert (at all). Flat roofs around here are massive trouble. There were a few cave ins from snow this winter, plus its been raining forever so the rest of the lot are leaking. Then again the tornados don't seem any worse to a flat roof than a high pitched one. OK unless your'e in a trailer... then you're toast. But I think your house would work well with one. The roof wont be truely flat, but if you have a parapet wall no one will know. Then you can have some cool scuppers for the water to drain from, or just some clay pipes instead.
Canales, Mark. Don't call them scuppers here. Ka nal ees
ShelleyinNM
I only spent a week out there once. Loved it! But didn't learn the lingo (obviously). One week -Phoenix, Flagstaff, Las Vegas then to Moab Utah for some offroading, back thru the Grand canyon, one night in Tuba city, back to Phoenix - then home to Ohio.
I should have known they were canales. This old house did one in Taos. Seems like they kinda overdid that one too... But they had canales, and vigas. They are vigas? right?
Si, vigas.
Here's what the adoberos say about cement. You lay them up with cement, you have the problem of expansion/contraction of dissimilar materials. You lay them up with mud, the wall becomes one mass of the same material. That's been true in my experience. However, you didn't give us your recipe, so I don't know how much one bag of cement represents.
If you've already sold your house, you're living somewhere else. Relax. Don't try to slam it up. Those suckers are heavy. Give it time to compress. That's why the 4 course/day rule. Don't let someone who's in a hurry to move on rush you.
You can still have vigas and decking with a pitched roof, doesn't matter. However, if you like the pueblo look, have it. You build this thing right and you'll get by with a cooler. Twice a year when you're working on the cooler, PM your roof. Recoat cracks in the parapet walls, make sure you've got a good pitch. Guy here that I respect swears by SolarTech 2000. You do a regular 3-ply roof and have them go away before the gravel. Then put it on. He's got a rental in Phoenix that he roofed this way in 1988. Went down this spring expecting to redo. Said it was still perfect. He's a civil engineer who has a home inspection co. here.
You said you were a mason. Don't get too anal about the adobes. First one we did, my husband put a level on each and every one. We laugh about that now.
ShelleyinNM
Dan,
I can't add much to what Shelley has written, she undoubtedly writes with the voice of experience. I agree with her on the mortar 100%. As far as I'm concerned the dissimilar materials have a potential for trouble that straight mud does not.
She is especially right about not being in a rush. That's not what adobe is about. Once you realize you are working to the nearest inch or two, and if you screw up (almost impossible) it's just mud, it's a fun material.
If you figure your grade beam or foundation is at least 8" out of the ground and you have a 6" bond beam at the top, if you lay up 4 or 5 courses a day you will be done in one work week. That's not bad.
The way it usually goes is a lot slower than that, and it isn't about the mud drying too slowly. <G>
DRC
Yeah, Dave's right.....just a week. I'm laughin' so hard that I can hardly type.
ShelleyinNM
Here's more on the reasons for a bit of cement in the, otherwise, adobe mortar mix.
The guys I know, who have laying adobes for ~20 years down here in the desert, say that they prefer the addition of cement because without it, over time the joints will erode faster than the adobes, especially those in an area that get hit by the infrequent, but heavy downpours we experience a few times a year.
Also, one guy said that for some reason, he had callbacks on a few houses (pre-cement) for where flickers (~woodpeckers) were chipping away at that mortar joint. The birds weren't bothering the adobes themselves, just the adobe/mortar joint.
These guys both do a "gloved-struck" mortar joint, that is, they don't strike the joints with an adobe spoon, but just brush it flat with their gloves or hit it lightly with a rubber-backed trowel (like the ones they use for stucco). This approach is taken for "style-reasons", but not striking the joint may leave the adobe mortar less-compressed, which may leave it more vulnerable to erosion during heavy rains and bird tampering! BTW, the hand/glove struck look is very rustic -- I kind of like it. But it's not a big deal either way. I suppose that adobe walls that are "spooned" do look more like brick walls, not a bonus in my opinion. But if there are good reasons to "hard-strike" the joints with an adobe spoon, I'd be willing to go that route. Remember that we are planning to leave our adobe walls exposed both inside and out.
Anyway, the one guy, who may be one of the best aboderos (by some people's account, anyway) in the Phoenix valley, says he won't even bid on a project where he can't throw some cement in the adobe-mortar mix. Maybe all the excuses are just to increase his volume of output, I don't know.
Sorry to belabor the point, but from what I know, a lot of rammed earth walls have a percentage of cement in them and it certainly seems reasonable to put a small amount, say ~5% (I don't know the exact amount), in the mix for adobe mortar.
At the end of the day, I'm not sure how I'll make the decision, but it's definitely a decision I'll have to make!
Thanks again for your contined comments -- at this point I'm interested in all the insights I can get!
Dan.
To be honest, I've never seen it done in exactly the way that you're describing. Around here they use mortar (bad) or mud (good). Some times it's too hard to go against the local grain. Tho now that I think about it I think I've seen some on trips to AZ. Joints looked off color and I wondered what they were laying them up with.
I think it's cool that the AZ code lets you leave SS uncovered. We can't, I think. Haven't seen the new code that was written for the IRC that we go to this month. My guess would be that he doesn't want to fool with getting the mud joints clean enough to be left exposed. Would require more work than simply adding a little cement to get it plasticky (is that a word?) and all the other stuff is just jazz.
I would suggest that you get a referral to a 5-10 year old job done in this manner and have a look. That should help you decide. You might also email Joe if you haven't already and ask his opinion. He's certainly tried everything there is to try. You'll probably have to nail down the percentage tho. Bob Barnes of OPA is very active in the regulation of the codes. He might be another to ask.
Since I cover mine outside and the house I have now is plastered inside except for two small "truth" holes, I only have my garden wall to look at. 60' long, 6' high. SS with SS mud, 5 years old, gently melting in the sun. I only have one crack. Vertical all the way up and down. Settling of some sort. None of those stair-step things that you see with cement mortar. Joints are not failing and woodpeckers not around.
One b4 that had at least one exposed wall in every room. Not a crack of any sort.
A follow-up question from one of your previous emails -- I tried Google for the SolarTech 2000, but nothing came up. Have the changed the name of the product, or do you know the name of the manufacturer. -- If I go with a flat roof, that is another key question -- foam or hot lay down, or __. Anyway, if you know anything more about thw SOlarTech 2000 I'd appreciate it.
Thanks again.
Dan.
I'll check with him. Thought that I was listening carefully since my next one may have some flat. I got the impression that it was some kind of elastomeric stuff and seems to me that he got it out of AZ. Will let you know.
ShelleyinNM
One very important consideration regarding flat v. pitched. Flat is a wicked anachronism, long outmoded by the availability of tin and persistent because of perhaps aesthetic and definite allusive qualities.
Once one has lived with a screwed-on tin over purlin and rafter roof, nothing else will do. And I'm not talking standing seam or colored Pro Panel. Just regular old 26 g corrugated. Imposing a flat roof on oneself is like placing a fine concrete driveway and then parking a Land Rover on it. Oil everywhere! Why build in a guaranteed pain, when there is no performance justification for it?
Once the railroads arrived with tin nobody who could afford it built a flat mud roof anymore. At some point in the past when newcomers were thronging to the southwest, it was realized that the "pueblo" look sold well; see "The Myth Of Santa Fe" by Chris Wilson. Mud roofs were replaced by built-up bituminous. There really is no consistency. It's largely a stage-set artifice that guarantees work to roofer's sons, and allows a romantic sense of spirit of place to enter the life of the owner.
Allusive romance is only one sort. Perhaps a better way to it is to allow function to infuse form with great immediacy. The owner builder is far better suited to this task than even a good residential GC who is forced to expedite. Charm is not expeditious as others have amply noted above. Charm at the expense of so much performance????????????
Design a really smart house that is more than a house. Design human habitat that's stingy with material and long on vision and build it well. Everyone will love you for it!
Lance in NM
Edited 5/12/2003 3:00:03 PM ET by Ethos
quick question, just what is your roof pitch? couple of years ago, blue print called for 1/4" in 12, I bumped it up to a whopping 3/4" in 12", least I sleep a little better. I would reccomend a torch down roof, installed by a known/proven Roofing Co., over 5/8 " plywood. I would read Lance post once or twice, for it sounds just like my stucco man.... way back when, when roof leaks were not thought of as problems. Good luck Jim J
o
The house is still on the drawing boards. I think the typical pitch around here for "flat" roofs is 1/2" per foot -- like you, I'd like to have it steeper. I tend to agree with the practical aspects of Lance's suggestions re: a tin roof with, say, 4/12 pitch.
Here in the Arizona desert "flat" roofs are everywhere. Rainfall is scant, ~8" each year, but if it's coming in through your ceiling, you're bitching! My sense just from talking with builders, roofers, and other homeowners is that the materials used to finish flat roofs have improved dramatically over the past 10 years. One piece of info I get routinely is that the quality of materials only goes so far -- it's the people putting the roof down, their quality of workmanship, that affect, hugely, how maintenance-free the roof is. -- Having said that, as I noted above, it's clear that a "flat" roof is risker and has a higher probability for need of maintenance than a pitched roof, e.g., with tin.
Right now, the roof is only one of 1,000 other decisions we have to make. If I was building the adobe in the hills of new mexico or Colorado, I'd follow the local vernacular and build one with a pitched roof. Here, yes, admittedly it's a matter of style (and perhaps the romance of the style). Or perhaps it's a huge joke foisted on the public by roofing companies! The problem is that once a person goes with a flat roof, it's their individual one, and despite all the roofer's claims (and depending on who wins the day in terms of, for example, whether to go with foam or hot-laid) I'm the one that will have to live with it.
-- Until I received feedback on this website to the contrary, I had thought all along that the new foam materials were supposed to be nearly maintenance-free -- that they were vastly improved. Now I'm not so sure. Sorry for the ramble! Just my indecision showing.
I'am in Prescott, where are you Dan ??
north of Apache Junction up near the Goldfield Mountains
Dan,
Don't try to save money on the roof. It's not worth it.
As I may have mentioned earlier in this discussion, I've fixed a lot of roofs in Phoenix.
Foam is just not going to be a reliable roof in your climate over the long run.
It's all good until the birds, rodents, or bees get into it. Then it's a big mess on top of your house that nobody wants to touch because nobody really knows how long it's ben leaking or how bad the structure underneath is.
A low slope foam roof can leak just enough to saturate and rot the framing but not enough for you to see a problem, and it can do so for a long time.
If you have to go low slope, go with torch-down (modified bitumen)from SWEPCO, EPDM, or one of the new UV-resistant lightweight membranes that have been developed recently. With a commercial-grade reflective coating, the reduction in your A/C costs will pay for the additional cost.
You've heard the old saying about quality doesn't cost, it pays.
DRC
Hi Dan, I am not a builder, I am a teacher, but my husband and I spent two weeks out in Arizona over winter break.......
There is a wonderful article in "dwell", a magazine dedicated to architects.......In the Jan/Feb2003 issue there is a house in the Tucson Senora desert constructed out of rammed earth.......My husband and I saw this house, it is awesome.......I wish you luck......
Dan,
I've decided that most readers of this site are not interested in this type of construction...so I'm going to share two of my secrets.
Don't know what Joe told you about sealing exposed adobe walls. Since I found my answer long ago don't know what the conventional wisdom is today. Some used to say log oil (expensive) or a slurry of drywall mud done with a whitewash brush (unsatisfactory). The answer is (drum roll) lacquer thinner and styrofoam (your latest trashed cooler). Just break up styro until the lacquer thinner seems to have dissolved all that it's going to. (Extremely scientific). Brush it on. Makes the adobes hard as a rock.
My second secret is what to do about the junction of the vigas/decking and the wall. Dissimilar materials again. We call this Shelley's Rope Trick. Rope.....just regular hemp....3/8"-1/2 depending upon the scale of your vigas and rooms. Brad nailer.....goes up in a flash. I saw it once in a coffee table book about historic adobes, and have been using it ever since. Those who notice always think it's a cool touch and most don't realize that it's covering what will become an unattractive crack/joint.
ShelleyinNM
Dan, Here's your roof info, tho I'm thinkin' that Lance pretty much hit it....but it's your design and your house. Sorry it took so long. You're probably about ready, aren't you? Adobes all layed up? :o) Me, I've been sanding and sealing about a million board feet of vigas, rough-sawn and corbels this week.
Reason that we didn't find it on the web is that Solar Tek 2000 is just one of many products made by E-Las-Tek in Tucson. http://WWW.elastek.com. 520-624-6282.
Like I said, I've never used it...tho someone I respect thinks it's good stuff. Since it's made locally you should be able to get plenty of referrals to old installations and decide for yourself.
ShelleyinNM
Hey Shelley, I posted a question on vigas http://forums.taunton.com/tp-breaktime/messages?msg=31349.1 that I was thinking you might have all the answers to...