[Cob] wood & cob footings

[jane at kirstinelund.dk]

This is what we do with our posts:

We make small concrete foundations ("point foundations", directly
translated) which will stick up 10 cm from ground level. while the
concrete is still soft we put in steel plates with holes in them, placed
on each side of the post, and screw the posts and the plates together.

For the two posts placed on the outside of the house we use special "post
shoes" (direct translation again) which will lift up the post a little
bit, preventing moisture to get in from the foundation. We have a rather
wet climate but it's probably not necessary in a dry one.

As for the "nothing" option - well, that was what our ancestors did, at
least around here. I know that some reconstructed houses with buried posts
last for 30 years or more. Putting a stone in the bottom of the posthole,
and maybe also some stones around the post, down in the hole, might lessen
the moisture problems. Charring the ends of the posts has been tried too,
but as far as I have heard, this doesn't help much.

Anyway, if you build a house with buried posts, make sure that it is
possible to change the posts. This was what our ancestors did, too.

If you use oak for buried posts, it is very important only to use the
heartwood. The outer layers of wood ("splint wood" in danish. Strangely
enough, my dictionary translates heartwood, but not the other word) rot
very easily, and will disappear in a few years, leaving the structure
weakened. This might apply to other types of wood also, but not all. Not
to coniferous trees, at least. In fir, the strongest part of the wood is
the outmost layers, just beneath the bark.

Jane