Expert: Richard Taylor, AIA - 3/4/2009

Question
Hello,
I am adding a 12 x 12 foot addition onto the back of my house. It will be a
sitting and entertaining area 2 steps down from my 12 x 15 foot kitchen
(which is being gutted and remodelled) I live in Toronto Ontario next to the
railway tracks so as you can imagine the winters are cold and the house does
shake with passing trains. I was hoping to have  smooth modern poured
concrete floors for the kitchen and new addition with underfloor radiant
heating. I am anticipating that this wish will come with a set of caveats for my
circumstances. What sort of considerations do you think I need to be mindful
of when sourcing out a concrete specialist for this project? The concrete floor
will extend to the outside and have large flor to ceiling siding doors and
windows. I have heard of a lightweight German product called Daro but I am
not convinced that this will give me the clean modern aesthetic I am going
for? Can you offer any suggestions please?
Claire

Answer
Claire - thanks for your question!

The look you're after isn't in the product you choose, it's in the finishing of the concrete - what you want is called "stained concrete".

Concrete is an incredibly versatile material; it can be moulded, colored, and finished in a wide variety of ways.  The process is pretty simple, but requires an experienced stained concrete artisan.  Experience is critical; you don't get a second chance with a stained concrete floor, once it's done, it's done forever!

The concrete itself is a different "mix" from typical concrete, made especially for accepting the stain and for achieving the super-smooth finish you're after.  Once the concrete's been placed, the color is added in a number of different ways including liquid and powder - depending on the desired result.

As the concrete cures, more color is added...finally the concrete is polished to the level of finish you want.  It's a labor-intensive process and fairly expensive!

Maintanence is important, too - most stained concrete floors require periodic waxing.

Since you want the floor to extend outside in your climate, you can't do it the same way we'd do it Scottsdale, AZ for example.  You MUST insulate the slab, and you MUST have a thermal break between the indoor and outdoor slab (it CANNOT be continuous through to the outside or it will crack and will be VERY cold on the inside).

You will also want to carefully consider whether the expense of the stained concrete is worth risking on the climate in Toronto - will it hold up or will it take too much of a weather beating for the expense?

Try these websites for more info:
http://www.stainedconcrete.org/
http://www.kemiko.com/
http://www.stainedbydesign.com/

Hope this helps!

Richard Taylor, AIA
www.rtastudio.com
www.rtaplans.com