The Speedfloor lid

To get that big heat sink we've been banging on about for our passive design, we needed some serious thermal mass. As you know if you've been following the story, (and there's more this week on stuff) we've chosen to have a concrete floor take on the role. The trick for me was that I didn't want the downstairs to feel like a rabbit warren of supporting posts. To get the open span we wanted then, we only had a couple of options and when Mr Building Boxes decided he really liked the look of exposed concrete ceilings, we actually only had one choice left.
Speedfloor is a proprietary system that is super simple and can span big distances without supporting posts. It's the slender steel beams that do the trick and of course there is a bunch of mesh in there too. When I say it like that it sounds like the most un-environmentally friendly thing we could have thought of, and it certainly wasn't cheap. But the plus side is that it will keep the house at a pretty constant temperature when combined with the insulation and ventilation systems, and will save money in the long run on heating. 
Unlike other systems, Speedfloor doesn't rely on a permanent metal tray to pour the concrete into, instead having ply as the base, which is then popped out to reveal the smooth concrete finish. And this is, coupled with the seven meter span, was what we were after. Like I said over on stuff, I'm not sure if I'll paint it or not yet, but Mr Building Boxes love it.
Me, I loved it with the water on it. With no wind, blue skies, it was an infinity pool to no where and everywhere. Shame there isnt one of those in the budget...