Sunday, April 10, 2011

Capping An Adobe Wall

Adobe can be an excellent choice for a privacy wall 
but in most climates it must be protected from rain and snow.

These first two photos show a brick cap.

The first one is in Albuquerque, New Mexico...

...and above is in Alamos, Sonora, Mexico.

The important thing with brick is to avoid cracks
 where water can migrate down through the bricks
 and into the adobe.

This typically means a concrete bond beam 
on top of the wall to mortar the bricks to.

I doubt that this wall above (in Silver City, New Mexico) is adobe
 but the cap would work on adobe.

I would assume the caps are pre-cast 
and they have been beautifully done.

With an adobe wall more of an overhang would be advised
 with a drip edge.

This cement cap was probably cast in place
 and has a pebble finish.

Again it is probably not adobe but the concept is the same.

Note the use of clay tiles on the parapet wall 
at the top of the photo as another idea.

Above is a good example of why a cap is important 
on this wall in Silver City.

A cement stucco finish has been applied
  and whether the wall is adobe or cement block once the stucco cracks,
 water seeps down into the wall
 and once it freezes there is more cracking,
 which leads to more water, more cracking, etc., etc. 

Stucco can be very strong in a single plane of a limited size,
but when it is applied over the wall on both sides,
three planes have been created - both sides and the top - 
subjecting the wall to stress cracks.

A cap creates two single planes,
one on each side of the wall separated by the cap.

Does any of this make sense?

Otherwise I love this wall and entryway.

I don't know how this cap was done but it looks great,
as well as the rest of the wall, which is in Alamos, Sonora.

Above and below are in Alamos, Sonora 
and show the use of broken glass to keep people 
from climbing over the wall.

This is common in Mexico 
but I am not sure I would recommend it here.

I would be afraid of a law suit.

This is a wall I built and of course it is what I would recommend.

The galvanized, corrugated metal on top
 was leftover end cuts from a roof project.

I securely embedded wood blocks into the last course of adobe
 and screwed the wood framing for the metal to those.

I can pull on the metal with all my weight and it doesn't budge.

The advantages are there is no heavy concrete or brick
 to lift to the top of the wall (or fall off),
 and the metal makes for a water tight cover with a good drip edge
 that will not wick back onto the wall.

With this type of a cap an adobe plaster may be used (as above)
that will not wash off.

To see more of the above wall check out my post: