building an horno

Driving through northern NM, one sees hornos (bread ovens) pretty much everywhere. They are especially common in the Pueblos, but are found in the backyards of many older homes. An excellent way to bake breads (and meat) in the summer, the ‘modern’ hornos are based on Spanish/Moorish designs brought over back in the 1500's. Built from adobe, all they require is the right mix of soils, water, and an afternoon. Unlike modern adobe bricks which contain additives to make them water resistant, adobes for ovens must be totally additive free - this makes the project even more do-able for the beginner - and are simple to make at home.

Recently, my family got together to help my father build an horno.  He has built with adobe for over 40 years and founded a school to help people build their own homes.

The base of this horno is dry stacked concrete blocks and adobes. The cooking surface is a single layer of redbrick. For this morning’s work (about 2 hours), four of us were able to mix mud, trim adobes and set 4 layers of bricks. The entire project could easily be finished in a day; add another day for a layer of mud plaster.

The first step is adding a layer of mud onto the bricks.

The interior diameter is sketched onto the bricks and the adobes added on top. Both sides should be level. The mud joints are smoothed with a spoon.

The doorway is made from redbricks set in mud. Each course starts with the door bricks and then follows around with adobe.  

Bricks are cut to size by chopping off chunks. Precision is not important because spaces can be filled with mud.

After the 2nd course, the bricks start to angle up on the exterior side.  Mud is added as before, but now more is added on the exterior edge than the interior one.

The process from now on creates a 2-d roman arch. The only technological assistant is a piece of rebar and flat stick with a line drawn to mark the interior diameter of the horno.

The adobes are placed on the mud, matching the interior edge with the line on the stick.  

Instead of checking level from side to side, the adobes must be level with the flat edge of the stick to achiive the proper angle for the next course.

 

And so it goes, course by course.  At the top the adobes will be nearly vertical and are held in place by friction with the mud.  Believe me, it works.  Once the last adobe is placed in, the ring locks into place and becomes very strong.  This is the process by which elegant adobe buildings were built throughout the middle east (and in some places sill are).

This is the process by which elegant adobe buildings were built throughout the middle east (and in some places sill are).  Shown here is a building in progress with a double roman arch doorway set into an adobe dome.  As lovely as it is outside, it is quite impressive inside looking up. 

Adventures in Shelving

Work in the kitchen is almost complete.  One of the last steps is installation of shelving.  Because the room is so small and relatively dark, I decided against upper cabinets and chose to have a single row of shelves across the wall.  I have to wait until the on-demand water heater is installed to put in the long shelf, but recently, Paul was able to work on the shorter shelf.

All walls in the cabin are solid adobe, but the south wall (along which the plumbing runs) has drywall covering the bricks.  This was the simplest way to deal with covering pipes and had the added benefit of creating a plumb surface along which the lower cabinets could run and providing an easier material into which shelves could be installed.

I don’t like the look of thick supports under shelves, but thought that something would be needed for support.  These shelves will hold all the dishes, so there is potential for a heavy load.  I bought some lovely cast iron brackets (see my Pinterest page for a link), but was still concerned that more support would be needed.  Better to go overboard, than have all my bowls crash down.

After consulting various online sources, Paul and I designed a variation of a torsion shelf based on two websites, one from popular mechanics and the second from a blog.

The first step was creating the hollow shelf.  A frame was made from scrap 1x2's, screwed and glued securely (you can see some finger wipes in the photo).   A skin of 1/4" plywood was glued on the top and bottom.  I wasn’t concerned about perfect alignment (although Paul was) of the various parts because I wanted to face the edges of the shelf with a strip of aged wood (see previous posts about the sunroom).  The aged wood would visually create a thick board, match the vigas, other finishes in the cabin, and just add to that casual, ‘rusticity’ that you see in old adobe homes.

A cleat was screwed into the studs on the wall.  As with the frame, the cleat was scrap wood.  It fits inside the torsion shelf and doesn’t show, so it doesn’t have to be attractive.  It does have to fit snugly, so Paul spent some time sanding to get the shelf well seated on the cleat.

The shelf is then slid onto the cleat and securely screwed onto it. This photo shows the prefitting, before the aged wood was added to the edges.  Interestingly, the adobe wall to the left is so out of plumb that when the shelf was level, it looked decidedly unlevel. We had to fiddle with it a bit to make it look good to the eye.   Ahhh, the joys of working in an adobe home.

Most torsion shelves are sanded and painted before the final install.  Visually the shelves appear to float and have a very modern look.  We installed cast iron brackets before adding the aged wood to the sides.  A side benefit of the torsion shelf is that we didn’t have to worry about the brackets not being screwed into a stud.  We did use expansion bolts (just in case) and the result is a very sturdy shelf.

What a nice shelf! Of course, it would be even better without the junk on the counter and through the house.