Adobe houses are made with mud+ straw dried bricks. How can they stand up to wet weather?
Mostly, adobe is used in climates which have little rain, such as the desert southwestern United States, and in arid climates such as Egypt. Adobe is a quick construction material which is not necessarily intended to last forever. If your house falls down, or melts in a sudden downpour, you can easily construct another.
In Egypt, adobe houses along the river often crumbled away when the Nile rose and soaked the soil.
And in Mesopotamia, archaeologists are frequently frustrated by finding indications of settlements for the period prior to the discovery of firing the bricks, for the very reason that even in that arid region the ruins have tended to “melt” back into the earth.
Two methods to reduce the persistent erosion include broad overhangs on the roofs, keeping the rain away from the walls, and the application of stucco to the walls–if the stucco begins to wear, it can be re-plastered to prevent the structural walls from eroding. (Interestingly–to me, at least–there are not many “adobe” cultures that have employed the broad roof overhangs. I have no explanation for this.)
Wind erosion can be a problem when it comes to adobe. The best preserved sites are often the ones who are tucked back away from the wind, and flying dust particles.
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It does seem strange to us when a culture doesn’t adopt what seems to be “common sense” in architecture, but humans tend to get “stuck in a rut” when it comes to building methods, especially if the culture is somewhat isolated from other influences, or particularly xenophobic. If everyone in your group has built their house in a certain way for generations, often innovation is ignored for the “tried and true.” In structures with low clearance, an overhanging roof might be more of a bother than it’s worth, what with cracking your head on it all of the time.
Also remember the semi-permanent nature of adobe. These people knew that their structures were temporary at best, but they were easy to repair or re-build. Groups that were migratory, or expected seasonal changes to affect their homes, such as the flooding of the Nile weren’t really interested in making their homes sturdy and permanent. In Egypt, rain wasn’t an occurance that happened often enough to force innovation to deal with it.
Also, in certain areas, there is a dearth of other building materials. Stone is difficult and time-consuming to cut and shape, and trees may be in short supply, or needed for other purposes.
Poverty may have had something to do with it as well. If you need to construct a home quickly in order to get to planting your fields, why put any more effort in it than need be? Gathering more material and spending more time on building a roof that overhangs might not seem reasonable, especially if you’re not expecting inclimate weather any time soon.
I think that people are getting the wrong idea about adobe construction. It was not always built with the idea that it wasn’t going to be there very long. This is San Jose de Laguna Church, at the Laguna Pueblo in New Mexico. Construction was started in 1699.
First of all, the mud used is a lot tougher than people give it credit for. The clay content in the soil in many of the places that adobe was used was pretty high, and when baked, that mud can get pretty hard. Ask anyone who lives in the Southwest and has attempted to dig through caliche soil. Also, the straw does help provide structure. Which is not to say that adobe is impervious to weather.
What adobe is, is labor intensive in terms of upkeep. They don’t just dump some mud walls on the ground and move in, happily spending their days in idle comfort. Erosion is a problem, and how it is fought is by constant mantainance. An outer plaster is put on the walls (I believe that the original plaster was also made of mud, although other materials may have been used when available) and it has to be constantly renewed and repaired. There is also the problem of erosion at the base of the walls.
Let’s take a look at the walls. The walls in adobe construction are a couple of feet thick. This has it’s advantages. Not only does it provide for strength, it provides good insulation, which helps to keep the houses cooler in the summer and warmer in the winter.
Don’t get me wrong. I wouldn’t select adobe as my building material of choice. It’s only for pretty arid climates and it is, as was stated above, extremely high in maintenance. But it is more durable than a lot of people think.
Adobe requires maintenance but so does wood. If you don’t paint your wood exterior the house is not going to last long. Pretty much everything requires maintenance although solid stone or concrete probably requires the least.
You know I have no idea if this is true of Adobe but a thought comes to mind regarding what happens to dirt when it goes without water for long periods. I live in South Texas. HEre we go for long periods withno rain then when we do get rain we get flash floods becaue the ground gets so hard when it’s dry for so long that it simply will not absorb water. When the flash flood subsides, some of the soil may be gone but that is more from the force of the running water than from seepage becasue the cracks in the ground from being too dry will still be there. Could that be a factor in Adobe bricks as well?