Sunday, December 14, 2008

Material Science

We've been hard at work to finalize all our finishes. The first major decision we made a while back was the floor material. We wanted to use a "green" material, so we considered reclaimed wood (like old hard rock Maple from gymnasium floors), Bamboo, and concrete. We decided to go with Bamboo, but there are a TON of different choices available - flat grain, vertical grain, strand, caramelized, natural, blah blah blah. To complicate things further, we are installing radiant/hydronic heat in the floors and many of the available Bamboos are NOT rated or guaranteed to work over radiant.

We pretty quickly narrowed it down to two main companies - Smith & Fong aka. "Plyboo", and Teragren. Both are very green companies, and both have some products rated for radiant. So far so good.

Another complicating issue is that many Bamboo companies CLAIM that their products are hard and resist denting. However, Cathy and I have visited quite a few modern houses that have used Bamboo flooring and it looked pretty bad - major dents, divots, etc. from bar stools, chair legs, moving furniture, and even high heels. We were really concerned about installing and expensive floor but having look beat up in 6 months.


(Stolen from XKCD)

I gathered up as many flooring samples as I could find - everything from Mesquite, Oak, Teak, and 20+ kinds of Bamboo. I then machined some tooling to fit our materials testing machine at work, which looks similar to this:

The tooling was a simple 1/2" diameter steel ball. The idea was to find out how deep the different woods would dent when the same load was applied - in this case I chose 250lbs.

This test is inspired by the standard "Janka Ball" hardness test (info here, here, and here) used on hardwoods. However, in that test they plow a 0.444" diameter ball into the wood until it is half buried, then measure the force it took to do it.

I'm sort of doing the inverse - applying a certain force (250lb) and then measuring the depth of the dent. I figured this might be more representative of normal use since most floors are scarred by relatively shallow dents and not crushed into oblivion as is done in the Janka test. I was also curious to see how the data compared with this different approach.

My Instron test rig looked like:

I wrote a little test program that ramped the force from 0 to 250lbs and recorded the displacement (depth) along the way. The raw data looks like this:

So, after all that, I got a bunch of data that I actually trusted (click here for a PDF version):

We were really happy with our old floor (White Oak), so I wanted to find something at least as hard as that. Based on my data, our Teragren Synergy Strand (Wheat) Bamboo looks like a great choice - nearly twice as hard as our original floor and pretty far out on the end of the hardness scale. Our second choice - the Plyboo Strand - was the hardest of all, but only slightly more than the Teragren. The Plyboo had little "microbevels" on the edges that we didn't want to see, so the Teragren was clearly the best choice for us.

Here's the wreckage from the testing:

Once we had the flooring selected, we were able to move onto selecting the wood for the custom kitchen cabinets being made by Woodmaster in Santa Cruz, CA. We are going with dark (espresso/chocolate color) Wenge wood. All the construction will be done with "green" and certified materials. The countertop will be white concrete with embedded rice-hulls made by Concreteworks Studio in Oakland, CA. The black/white combination should be pretty stunning.

We are also trying to do a bright orange bar on the kitchen island. However, we are having trouble getting the right shade in concrete, so it may end up being Caesarstone "Tequila Sunrise" quartz instead. That should "pop". Plan B is to go with the same concrete as the main top and to use some hot color on the backsplash instead.

The other place we've been spending a lot of time is the master bathroom. We're doing pretty dramatic in there as well - a black tile floor, caramel bamboo cabinets, white concrete vanity top, and "Citron" yellow/green tile in the huge double shower. The tile is from the "Claymonde" series from Fireclay Tile in San Jose.

Cathy is totally in love with that tile (she picked it out over a year ago), so we've worked to find things that would work with it. I'm thinking the shower will literally pop off the wall when we are done.

One of the other really fun materials we've found is Panelite. It is an architectural glazing material (model is AO/GCL) and is made of two layers of thin fiberglass with a thick (about 3/4") layer of expanded aircraft aluminum honycomb in between. The composite sandwich is translucent and has the very cool property of "pixelating" any backlit object behind it.

We are probably going to use it for the sliding "barn door" that is between the end of the hallway and the family room.

Anyway, that's a good smattering of some of our current material choices. As we were telling a friend today, we've made some final decisions, in some cases we've made them several times, just to be sure :-|

At some point I'll tell you about our (ongoing) search for plumbing fixtures...


Blogger contraption said...

Don't forget to look at the "Roof, Windows" post I put up yesterday!


December 15, 2008 7:47 PM  
Blogger sylvan said...

I am one of those people who spent a lot on bamboo floors because they were supposed to be so hard and I am very disappointed. They dent if you look at them too long. I would not recommend bamboo. I previously had hardwood floors and they were bomb-proof.

If you do go with the bamboo, I'd recommend sanding the coating off and sealing them with polyurithane before you use them. After a year (with no kids and no pets) our floors are very damaged.

December 19, 2008 4:05 PM  
Blogger contraption said...

Hi Sylvan (whomever you are),

Good thought about the polyurethane, our Oak was "Varathaned" which I think helped a lot with preventing scratching. The floors we pulled out (sadly) were really in quite good shape even after 9 years.

What type/color of bamboo did you use?

December 19, 2008 7:05 PM  
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