Thursday, July 31, 2008

See-ment Floors

Here's a post I had begun working on in early May and then promptly forgot about while more pressing matters were at hand. Here it is slightly modified for your reading pleasure today.

While the wood floors in our kitchen and bedrooms are being installed, the giant sandbox of our dining and living rooms is quietly leaving us and our new concrete floor awaits. Yep, we're using exposed and polished concrete for our flooring material in our living and dining room. (For the record, Jethro was incorrect in calling the swimming pool the "cement pond" and added to the confusion over the differerence between cement/concrete). Concrete. It's hard. It's simple. It's gray, it's durable, it's cheap. It's relatively simple to make. You take some sand, aggregate, cement and some water, mix them together and there you go. Not much has changed in the 2,00+ years since the Romans started messing with the stuff to build things like this. We like the look of concrete and the fact that it can be a finish material all by itself and doesn't need covering up with other materials. It's thermal mass will help keep our feet and space cooler in the summer and warmer in winter and we'll not worry about scratching it or spilling something on it because, well, it's concrete.
We did add piping underneath the slab, so we can have infloor heating someday if desired.

Concrete is a great material, but the embodied energy in one of its principal ingredients - cement - is actually pretty high. It is non-renewable, needs to be mined from the earth and quite often shipped from a great distance to reach a local production plant.

Consider this: "Two and a half months ago, a ship left Thailand loaded with Portland cement. It spent three weeks crossing the ocean and another week going through the Panama Canal before docking in New Orleans, where its cargo was transferred to barges. These barges then spent six weeks traveling up the Mississippi to Minneapolis, where the cement is now arriving at batch plants for use in concrete. Over 80 million metric tons of cement were produced last year in the U.S., but another 20 million were imported to meet the demands of our booming economy." EBN June, 1999 A view of the concrete floor just after it was poured. Our concrete contractor, Buckcrete, cane back in a day or so to cut in the joints. 28 days later, after the concrete had a chance to cure and come to full strength, we polished it to a nice terrazzo like sheen.
Polishing and sealing the floors.

One of the ways to reduce concrete's embodied energy quotient and carbon footprint is to reduce the amount of cement used in it's production. We can do this through the use of fly ash, a by-product of coal burning that would otherwise find its way to a landfill somewhere. By substituting a generous portion of the cement with fly ash , we've reduced the carbon footprint of the concrete while at the same time making something that looks good. The fly ash gives the concrete a slightly darker shade, and is denser, stronger, and richer looking when polished. The polishing makes it look pretty but is also a healthier choice because the polishing tightens up the pores in the concrete it retards staining. This way we eliminate the need for an additional sealer that needs to be reapplied every few years. We just have to be willing to wipe up spilled wine within 24 hours if we want to avoid some staining. Then again, some patina is kind of fun!
Polishing and sealing the floors. Wine is not the only thing being spilled on our floors....

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