posted 7 years ago
Hi Christian,
I just ran across this thread and thought I'd tell you about my experience/ observation.
My garden was originally a mill pond but around 10 years ago it was filled in with in very heavy clay soil and thus the drainage is terrible and the ground soggy much of the year. I'm in the process of building a small house with attached greenhouse in my garden and was very worried about drainage. Therefore I dug a 70 cm deep french drain (with 100mm perf drain pipe and gravel) all the around. The french drain can drain away from my garden to lower ground. The area under the house is dug out to a depth of 40 cm for insulation and I was concerned it would fill with water but it is actually staying very dry there. Now I'm even considering skipping the capillary breaking gravel layer. I had expected the french drain would also drain the water a certain distance outside the drain but not so. Even 0.5 m outside of the french drain is still just as soggy as before.
I'm using a point foundation with precast cement carport stolpers (posts?) sitting on top of 40x40 cement fliser (pavers). Not very green but I was concerned with wooden posts rotting. Now that I see how well the french drain is working, I think a rubble trench foundation with embedded wood posts might have been OK and would certainly have been less expensive.
On a side note, when I moved to Denmark 8 years ago, the $50 and up book was one of the dozen books I brought with me. Even though I'm not building so cheaply and simply on my current project, it has been like a roll model for me and helps me remember to think about how I can build with less. And when I have B&B guests that are interested in natural building, debt free living, green transition, and similar, Mike Oehlers $50 and Up book is one that I often show them.
Regards,
David