“you’re going to live in a…mud…house?” someone who had seen this blog said to me recently. it was clear she seemed to find the idea a little, well, eccentric.
and equally clear that like many people, she didn’t realize that adobe bricks are, in fact, made of mud. that’s correct, folks: if you live in an adobe structure, you, too, are living in a house of dirt.
‘course, these days most adobe houses are made of what’s known as “stabilized adobe” which means that something has been added to the mix–usually portland cement, though sometimes asphalt–to make the adobe less prone to washing away.
as it happens, last spring when we first began looking at our barrio house, i was taking a materials & methods class. each class member chose a building material to explore in more depth, with options ranging from metal to wood to concrete and to, yes, earth. i’m sure you can guess which one i picked.
so, as chris and i were debating whether or not we were going to take our real estate plunge, i was simultaneously up to my elbows in mud pies in our garage. rather than playing with adobe bricks, however, i decided to explore rammed earth (check out the tucson mountain retreat house by DUST and its gorgeous rammed earth walls and you’ll see why). my process involved collecting samples of dirt from across the tucson basin, mixing them with varying percentages of portland cement, and then pounding them into metal molds i’d thrown together in the shop on campus with the spot welder. once i had them out of the molds i tested them for weather resistance by dousing them with water (the portland cement makes them amazingly durable).
traditional adobes, however, don’t contain any cement. they’re made of dirt (ideally with a heavy clay content), water and usually straw to create a sort of sticky slurry that (today, at least) gets thrown in a mixer, then into wooden molds corresponding to whatever size and shape you want your adobe bricks to be. earlier this year i did a workshop out at canoa ranch, south of tucson, where we made adobes. basically, once the mud mix came out of the mixer, we simply took up huge handfuls of it and slapped them down into molds (this made, it must be said, a really satisfying splat) which had been sprayed with water inside to prevent sticking. the trick after that was to get the bricks out without creating hairline cracks, which could potentially cause the dried bricks to fail. finally, they got set out to cure in the sun.
they’re going to–and have–used the exact same process to make adobes at our barrio house. though we haven’t been able to do much yet in terms of construction (there have been so many code violations at the house in the past that the city wouldn’t even allow us to turn on temporary power without official building permits in place) over the summer a crew did get started on making some of the many, many mud bricks we’re going to need for repairs. while they were there, our friend susan denis snapped some pics.
as you can imagine, the process of making adobes is rather labor intensive (and these guys were doing it in july in tucson!). which, yes, makes it rather expensive–at least in the u.s. traditionally speaking, though, building with mud was cheap (and it still is if you have the time and people to do it). to build our house, the original inhabitants simply dug a big hole–no need to buy materials–and used the dirt on site to make their walls. this is the reason we have a big cellar under what will be our living room: it’s the crater from which the house was born.