Quiet couple of weeks, with the earthworks guys finishing the shed sand pad and then I hit a bit of a block – waiting for concrete people to be intelligent at me, and we also had “the storm of the decade” come through and make the entire city rather soggy for the better part of the last week. Thankfully the sand pads have survived the rain unscathed.
The rain cleared today, and since concrete people were still being slow at me I decided to start on the house foundations – I’d been torn between doing this part myself and letting the concrete people do it, but they’re all being a bit teary at the complicated foundation arrangement (see below) so I’m 90% convinced I’ll just do the formwork myself.
First step was to translate the survey pegs into string lines, which turned into a fun day of putting together hurdles, making them the right height (the theory is if I make the hurdles the height of the upstand then I can use my string lines to check the height of the top of the formwork) and then running string lines to the hurdles – made more fun by having to translate the survey pegs up to the string level.
At the end of the day I had a nice cat’s cradle of string running all over the place, ready to start digging holes tomorrow.
I don’t think I’ve talked about the foundations before, so I’ll mention it here – this is an idea I borrowed from my architects, who used it on their house. I’ve seen other strawbale builders use it as well.
The fun part of this foundation arrangement is the 100mm upstand under the strawbale wall. This has a couple of functions:
- If the house ever floods, it stops water from getting into the bale walls
- On the outside, that 100mm of exposed concrete functions as the required termite barrier without having to use chemical treatments. (pipes and other penetrations through the slab will be protected with stainless mesh).
The other feature (also stolen from the Wetjens 🙂 ) is the 100mm C-channel on the inside edge of the upstand – this is a convenient services duct for running power and other cables.
The downside of all this is having to run formwork for the upstand somehow suspended in mid-air. The Wetjens discussed their solution to this, along with a familiar-looking diagram, during their build, but I’ve had a couple of alternative ideas that I’ll play with along the way.