foundations are their very own thing. everything needs them, everything is reliant upon them doing their job. skimp at your own peril.
i thought long and hard about the type of foundations i was going to need. i had plenty of time to think, plenty of time digging to think. i had several ideas, some of them were possible, some of them weren't. given that i am trying to build on the side of a mountain, i hoped i would be able to tie into the bed-rock and not have to dig deep footings.
there was one other issue, other than ground conditions that helped determine the finish height of the foundations, that was the two extensions that have to be segued into. i needed to finish at something the right height in order for this to happen. that meant i couldn't go too far into the ground, or too far up.
i wondered about shallow trenches infilled with crushed stone i had reclaimed from clearing the over-site, but in the end i didn't have to dig any trenches, but build forms. i set a level from a building line i described in-front of the old main building. dug down until i hit solid ground and excavated back, into the mountain, on that level.
even though the grade beam (a strip foundation laid at ground level) wasn't that deep, i used 4 continuous lengths of 10 mm rebar to ring round the foundation. at pre-described intervals i set in formers where i want to tie down the timber frame into the foundation with threaded bar.
given the relative small size of each section of the foundation, its distance from the road, and its cost, there was no chance or point of getting a ready mix delivery. so i had the dry materials delivered, mixed it, poured it and set it.
this is the chute i constructed to ease getting the sand and stone down, to save me having to barrow it, and to get it to the only place i could house it.
my feeling about using concrete in building houses is this. keep it in the ground. i'm not building an NCP carpark. its just not necessary, and there are far more preferable ways to construct. unfortunately, here in Portugal, it seems to be regarded as the only material to construct with. i would like to show people that that just does not have to be the case. that there are friendlier, more tactile, more efficient, cheaper, sturdier, more versatile materials available. principally timber. but then i would say that, i'm a carpenter.
in total, it wasn't more than 15 cubic meters of concrete, which isn't a lot if you have it delivered. mixing by hand is another issue. but in overall terms not that big a deal.
having said that, concrete is a superb material for foundations, and i would not eschew it, just on the basis of apeasment to green lobbyists. my rationale whilst building this house is that it has to be as cheap as possible, essentially free if it can be, aswell as fulfill all the structural requirements and be as aesthetically pleasing, and as finely built as possible, to the highest achievable standard. be as green as you can be, but you don't have to be an idiot just for the sake of it. use the right material for the job.
i stepped the foundation to help prevent the ingress of damp or water onto the timber frame, effectively creating a gutter all the way around the frame.
i'm writing this to show what you can do when you set your mind to it. knowledge you can come to. ideas you can find. heart, you need to have.