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Post date: Jul 12, 2017 3:13:57 AM
Adobes are heavy. If they are above windows and doors some structure is needed to prevent the wall from collapsing into the hole presented by the window. That structure is often a lintel. In this case the lintel is a beam of Douglas-fir. In the photo at left you can see that the height of the lintel is the same as two courses of adobes — twice as thick as the wooden sill under the window.
Here the lintel is recessed on the inside. In pueblo architecture the lintel is exposed on the outside. We shall have to wait to see how it is handled on the inside in this house.
Opening for Window, with Lintel
One small problem with embedding wood into adobe walls is that the wood is never completely dry when the wall is built. That means the wooden blocks will shrink as they dry, pulling away from the masonry walls. That is seldom a big problem, but in an wall it can leave a place for water to enter the wall with wind-driven rain.
Adobe walls are not reinforced. In an earthquake with strong lateral (side-to-side) shaking the wall will probably crumble. Concrete block walls require that some of the vertical holes in the blocks be filled with concrete reinforced with steel to form vertical beams within the wall. In addition, every few courses are reinforced horizontally with a ladder made of steel that is embedded in the mortar between courses. Neither of these techniques seems to be used with adobes. (In some houses the corners are cast of reinforced concrete before the adobes are laid.)
However, at the top of the wall is cast a reinforced concrete bond beam. Not only does this bond beam reinforce the wall but it also allows the builder to embed bolts so that the roof structure can be firmly tied to the walls, just as the walls are firmly tied to the foundation. This prevents the roof from blowing off in a very strong wind.
In the photo at right we see a corner where the height of the adjoining walls differ. You can see the wooden forms to keep the wet concrete atop the wall and also see the steel making the transition of heights. These walls are of different heights because there will be a shed (sloping) roof which is lower on the left. The hole in the wooden forms will be filled after the reinforcing steel is tied together and correctly in place. Then the two sides of the forms are connected at the top so that they don't spread apart when the heavy wet concrete is poured.
Changing
wall heights
At left you can see the bond beam after pouring the concrete but before the forms have been removed. What does not show is pieces of wood connecting the two sides of the form so that the weight of the (wet) concrete does not force them apart. After the concrete sets the wooden forms are removed.
At right you can see this concrete bond beam above a window. The bolts poking up out of the concrete are for fastening the roof structure to the wall. You may also note that the lintel (above the window opening) has been padded with wood so that the courses of adobes line up.
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