Since our last post, we continued digging a 40" trench for all four sides of our 12x12' bathroom structure. Oh, how we love digging. We took turns heading up to the compound and trenching on alternating work schedules to get it done so we could move on to a more exciting, and definitely more labor intensive phase of the project: forming and pouring our 8"x40"x12' footer. By hand. So that's how we've exhaustingly spent the days since our first post.
Step numero uno - dig a huge trench, somewhat larger than the piece of concrete you intend to make occupy it. Because we like digging so much, we additionally opted to dig about and extra 6" under the house, exposing the existing foundation so we could encapsulate the existing supports in new concrete (some of which were just stacked bricks! Those monkeys...). We did this to reinforce the foundation of the backside of the house – read: reinforce our confidence in the house remaining upright – and to support the new structure and the wrap around deck we've got planned.
We did our homework, and if you ask 10 different masonry people about how to build a proper footer, you'll receive 10 different answers. Things get muddy. Generally speaking, you do need a deeper footer if you're building in an area that is prone to radical temperature swings – which we most definitely are – so we opted for about a 40" footer. If you're familiar with the expression, "If you can't tie knots, tie lots," that's pretty much the exact general methodology we're employing throughout this project/life. Being slightly over-engineered is a whole lot better than having your house collapse in the middle of the night.
After digging, the next objective was the form. This part is deceptively tricky. Think "Trix Rabbit with a meth problem and no lucrative commercial deal" tricky.
Since you have to start somewhere, we started with the outside perimeter, plan being we could then simply create a smaller box within it. The process involves an exhaustive and seemingly endless cycle of leveling, squaring, and repeating. With it all being interconnected, every change you make has an effect on every other part, so meticulous incremental adjustments are necessary. It's like continuous form-building karma.
EVENTUALLY, we got it. We wound up using a finishing nailer instead of screws to make construction easier, while simultaneously making the occasional deconstruction much more difficult. In order to keep our 8" width uniform, we nailed boards parallel to the top. And as a neat surprise, these turned out to double as extremely useful braces when we poured 14,000 lbs of concrete into the forms.
Something should also be said here for rebar. We found a lot of people who swear that rebar isn't useful in a small scale application like this, and maybe it isn't. But you just never know what's gonna happen. For instance, we ended up running short on concrete, and had to divide the pour into two separate days. If it hadn't been for our rebar skeleton, this could've been a major disaster: wet concrete doesn't stick to dry concrete. But it will stick to rebar. So our skeleton was key to keeping the two separate pours firmly attached. We pounded 3/8" and 1/2" rebar 18" below our footer into the ground and standing about an inch above the entire footer's surface. Side note: Austin is a rebar-pounding-PRO from Burning Man construction.
Next up was making sure that our forms were well supported and strong enough to hold the insane amount of weight we were about to dump into them. To accomplish this, we did a little back-filling in the trench space exterior to the forms, using dirt and cinder blocks salvaged from the old steps, and huge steel beams that our neighbor has been trying to pawn off on us since day one. We finally gladly accepted.
Finally, it was time for the concrete. In keeping with the DIY ethos of our project, we used bags instead of getting a truck up to the compound (also considering it's prohibitively expensive to get them to drive up into the mountains for a 12x12' footer). The first day we picked up 2 pallets, totaling about 5,000 lbs., and requiring two trips up the hill. This unbelievably turned out to not be enough. So we grabbed a third pallet on the third day, and we were in good shape.
So we mixed and poured and leveled... and mixed and poured and leveled... and did it again and again and again. We used a single-bag cement mixer, wheelbarrowed, bucketed, and poured it into every inch of the forms and surrounding the existing foundation, one 80 lb. bag at a time. And after two days, VIOLA – there you have it. We have a footer. Easy peazy.