Tiny house foundations

You know that we’re working on 3 small buildings simultaneously – one is going to be a paint shed and the other two would have been called ‘sleep outs’ in the 60’s but we now call them tiny houses and it’s much cooler, right?  Because the buildings here at Chestnut Farm don’t contain cooking or bathroom facilities, they’re not fully fledged tiny houses, but the basic challenge of constructing a small building is the first hurdle for prospective builders, so I’m hoping these posts will help you pick up a few things.

I want to show two different ways to build tiny houses; one with post and rail construction to support the walls & roof, and the other featuring pre-fabricated (on site) stud framing fixed to plain concrete slabs.

On Monday, we finished the low formwork (or ‘boxing’) for the paint shed.

The posts were put in last week (see previous post)and some cross timbers added for support and also because we can add them without them getting in  the way of pouring the slab.  Post and beam is much quicker than stud framing, and uses a lot less timber.  You need heavier timbers, but fewer of them.  One disadvantage of round posts is that they get in the way if you want to line the building.  Note that the slab is off-set from the posts, so that the posts will be integrated into the slab.

The offset is the same distance as the beams are thick, so that corrugated iron fixed to the outside of the beams will slide down neatly against the side of the finished slab

After finishing the formwork at the paint shed, we jumped across to the Apple House site.  This will be the same size and shape as the paint shed – 2.4 m x 4 m.  (If you’re thinking of a tiny house, mark this out on the ground and walk around in it: it’s a very human-friendly shape for a multipurpose room)

The Apple House is adjacent to the top dam and will nestle behind the seedling apple which is at its NW corner.  We’d shifted some fill during the dam renovation in December, but were (yesterday!) lucky enough to get another 6 ute-loads from a nearby housing development.  These extend the ‘bench’ around the building – meaning we can build a small level garden around the building, which will be aesthetically pleasing, but also fulfil a key structural function in resisting any movement (under the slab) of the fill from the dam.

Jump ahead a few hours and here’s Clem rechecking that everything is level and that all the distances are right.  Once you’ve checked all your sides are the correct lengths (the short ends are 2.4m and the long sides are 4 m) the key test is to measure the diagonal from corner to corner.  If those two distances are the same, you have created a rectangle.  If not, and your side measurements are correct, your corners aren’t at 90 degrees – you’ve created a parallelogram.  (If that happens, a bit of shuffling of timbers should get it right.  Easier to demonstrate than to write about!)

This big pile of fill – mostly topsoil mix – came from a local earthmover, Paul Mullane, who I highly recommend.  Top operator and great guy to boot.  Paul was doing a job in Wendouree, heard we needed some more fill and dropped this off at about 8.30 am.  It provides a heap of further support for the fill under the slab – we’ll also spread some on top of the clay fill we’ve already spread around the Apple House site.  It’ll help our garden grow – thanks, Paul!

Meantime, with the side timbers in place (note small timber pegs at strategic points), I started shovelling a shallow trench around the inside edge of the future slab.  It’ll be about 350 mm wide and 200 mm deep, whereas the rest of the slab will be only 100 mm deep.  The thicker edge makes the slab stronger and is located near the edge because that’s where the weight of the walls and roof come down.

Lunchtime and Clem & Jackie have already got stuck into Paul’s load of fill.  Some is spread around the base of the apple, and some on the exposed walls of the dam.  We’ll spread more around the South side of the Apple House (where the straw is) tomorrow.  [The straw was there in case it rained – clay subsoil is disgusting to walk on once it gets wet!  It sticks to your boots and you walk it everywhere!]