Friday, December 2, 2011

Masonry and wood

Corrado “Junior” Soprano:   “My father was a master stone mason.  He never cut fucking wood.”

-          From HBO’s “The Sopranos:  He is Risen”

Masons are known to sometimes be contemptuous of wood as a material, and of carpenters and carpentry in general.  Yet wood often plays a critical role in masonry construction.

Wood is tough.  In engineering terms, this means it is less prone to crack propagation.  Wood is also much less dense than stone or concrete.  It is also a good thermal insulator. 

Wood is sometimes used in a masonry type of construction, known as cordwood construction, stackwood construction, or stackwall construction.  Cordwood consists of logs that have been cut into lengths which are suitable for burning in a fireplace or woodstove, around 16 inches to around 24 inches in length (~40 cm to 60 cm).  This wood can be split or left in the round.  The length of the logs is the thickness of a wall to be built.  Nice thick walls: very strong and good insulators.

To build a cord wood wall, the logs are simply stacked as one would stack firewood.  A layer of mortar is placed between logs, much in the way mortar is placed in beds between rows of stone, block or brick.  The only real difference is that the mortar is typically half mortar and half sawdust.  This makes the mortar a better insulator, and much less expensive.  Sawdust in large quantities can usually be obtained from your local saw mill, either for free or very inexpensively.  It is simply added to dry mortar, dry mixed, and then further mixed after water is added.  For greater strength, holes can be drilled through the logs and they can be spiked together, as is being done in the picture below.

I am currently building a combination log cabin/cord wood building.  I’ll be using it to contain a sauna, with a bedroom upstairs.  The upstairs walls are all cord wood construction.  Some people like to include glass bottles in their walls to allow light to pass through.  I used a bunch of handblown glass spheres in my walls.

I must warn the reader that if he or she ever decides to do this, one must be very careful with the chainsaw.  I almost cut my left foot off last week.  I’m sitting here typing now with a big cast on my foot; I’m very lucky I didn’t lose my foot!  I just got back from a week in the hospital.  I had to be flown out on a helicopter.  Please be cautious.  I was working alone.  I knew better, but was racing the onset of winter.  If I were a master stone mason, I would never cut fucking wood, and I would never cut my fucking left foot.  Foolish me.

I apologize for cursing on this entry to those who may be offended, but it really hurt.

Here is a picture of the finished sauna building: