Monday, December 8, 2014

Building An Adobe Wall: #3 Putting Up Adobes

In the above photo we have just laid up the first three courses and are starting on the fourth.

The above photo also shows how we installed the first two gringo blocks,
in this case to be used for the gate jamb.
There will be a total of four gringo blocks on each side of the gate 
with two (in alternating courses) at the bottom and two (also alternating courses) at the top.

In setting the first gringo block you want to be careful with the placement
 as it will determine the location and width of the gate since the next ones on top should be plumb to it,
(as well as the adobe bricks that form that end of the wall interspersed with the gringo blocks).
As you can see we have carefully filled the gringo block with mud,
having packed it in tight. 

The gringo blocks also tend to slump in the mud 
so care should be taken to have plenty of mud mortar underneath
 and keep them level and plumb as you go.
Adobe bricks when placed in the mud mortar
 will suck the moisture out of the mortar very quickly firming up in the wall.
Gringo blocks are just the opposite in that they are not absorptive at all,
making it easy for them to slump in the wet mud mortar.

Now here is where we start to take much more care as we build our wall than is normal.

In the above photo Allison is carefully spreading the mud and packing it in between the bricks.
We like to make the mud mortar as thick as we can
 since we feel it is much easier to make mud mortar than bricks.
 Making the heavy adobe bricks are a multi step process which requires handling them several times
 before they find a home in the wall or if you buy them they are very expensive.
Mud mortar on the other hand is cheap and easy-
mix it, put in the wall and move on.
Make and use more mud mortar, make or buy fewer bricks.

To see how I made these bricks please go to the post:

Also, most adobe practitioners hurriedly put the mud down, throw a brick on top,
 leaving many holes in the mortar with the idea that the plaster or stucco will key into those holes.
We on the other hand believe the integrity of the wall is much stronger 
by working and pushing the mortar into and between the bricks.
Adobe mud in the bricks, mortar, and plaster creates a bond by compression
and packing the mud in tight creates a much stronger compression and wall.
This adds extra time to the process but makes for a much stronger wall.
The plaster will adhere to the wall with the straw fibers that stick out of the bricks and mortar, 
as well as the intrinsically rough surface of the adobe.

Lastly we generally do not wet the bricks before putting them in the wall
 but we do wet the tops of them before putting down the next layer of mud.
This is all a factor of the temperature, humidity, and direct sunlight. 
If it is hot and dry you may want to keep things a bit wetter.

The section of wall in the above photo is complete for the day
 and notice how the mud has been packed in tight in the joints.

Also notice that we are setting up our coursing to have 14" wide pilasters at each end 
with a 10" wide inset that will form an arch of sorts reflecting the 10" x 14" size of our bricks.
On the far right pilaster this requires us to build out every other course to keep the 14" width
 as the coursing we are using calls for a 10" wide brick over a 14" wide brick.
I like to do that build out as we go because the mud adheres much better while the wall is still wet.

There is a limit to how high you can safely go in one day 
as the wet mud mortar can only accommodate so much weight on top of it in one day, 
again depending on temperature, humidity, and sunlight, 
before the wall could begin to topple.
The dry adobe bricks will absorb a lot of moisture from the mud mortar,
but in general I only like to go four or five courses in one day.

A few of the hand tools we use are from left to right:
1 1/2" and 2" margins trowels for packing in the mortar,
an old hatchet for cutting the bricks to size,
a larger trowel for scooping mud,
and a masons hammer for trimming bricks to size.
We use a shovel to get mud from the wheelbarrow to the wall 
and 18", 42", and 8' levels.

After the third course we put down a layer of stucco netting in-between every other course
as an option for strengthening the wall; strictly optional and we had the stucco netting at hand.
In the photo above we have put down a thin layer of mud, then the stucco netting...

...and then we put more mud on top before setting our bricks.

Every couple of courses I check the level to keep things in a reasonable range.
Also be sure to keep your wall plumb as you lay up your adobes 
paying particular attention to the corners.

We continue going higher and we have started forming our arch 
using both our bricks and mud build out to get the shape we want.

We also continue to tightly pack mud in any recesses in the wall,
slowly building out to an even plane while the wall is still damp.

The hatchet and mason's hammer are ideal for fine tuning the arch after the mud has dried.

By this point in the process I like to have the the plane of the wall filled in 
ready for the first coat of the eventual adobe plaster.
Once the wall starts drying I do not like to fill in or build out as the wet mud 
does not adhere to the dry wall nearly as well as when the wall is damp.

We have one more course to go that will entail setting wood brackets in between the bricks
for attaching the framing for our cap which we will look at in the next post.

All of the posts to date are: