Concrete

posted Nov 21, 2013, 4:00 AM by Paul Halliday   [ updated Dec 4, 2013, 6:20 PM ]
Concrete is one of my favourite building materials. It is incredibly versatile, strong (when used correctly), low maintenance and just plain fun to work with. All of the counter tops in my home are concrete (see Building a House about 3/4 down the page) and even more recently a bar on the deck.

After adding a loft over my kitchen last year I ended up with a support column a little too close to my wood burning stove. Moving the stove wasn't an option, however I could get around the reduced clearance by using a heat shield. Sounds like an opportunity to use concrete to me!

I built a form 48" x 11" and 1 1/2" deep. I then put in a piece of re-mesh the size of the mold. Lastly I mixed an 80 pound bag of high early stone mix with 1/2 a bottle of black concrete dye (1 bottle will do 2 80 pound bags). The piece sat for 72 hours and then was polished with 50, 100 and then 200 grit diamond pads (took about an hour).

I also added some old climbing gear as inlays for the piece which were attached to the inside of the form with super glue prior to pouring. The piece is still pretty wet here but the result is pretty cool:

   
Once the pieces had rested for a couple of weeks I applied 4 coats of a water based sealer. The sealer simply protects the pieces from surface stains and also provides a uniform matte finish.

Mounting was pretty simple. I had some pretty complex ideas going through my head when thankfully Occam smacked me in the face. These angle brackets were incredibly simple to make. For each piece I used a 3" chunk of 1/8" steel angle attaching one piece to each slab with 1/4" drive pins:
 

and the other with small lags to two faces of the column. I had a hole drilled through the center of  each bracket that let me join the pieces with a 3/8" bolt. So simple.


The brackets that these pieces rest on were a little fancier and really didn't need to be. I think I was just looking for an excuse to weld something ;). Actually, I did think it through a bit (dead load verses a cantilever) plus it did make positioning and mounting each piece a lot easier. 


This is what the final product looks like. Hopefully it works..


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