Excited to join this community, I've been a voyeur for too many years, so I'm coming out!
My wife and I moved to the Limousin - Park Regional du Perigord Nord, from Finistere in Brittany 3 years ago, to a 2 1/2 acre greenfield site, half wooded. Have built a 1200 ft open fronted barn and half way through the framing of a 400 ft version of our planned house. Had great intentions of using our own lumber etc and no concrete. Ended up with a concrete base, stem wall and milled lumber 6 x 2" for the octagonal framework. Im not a builder and this is a retirement project, us both being in our 60's. So everything came to a stop last October, I wasn't happy that we'd drifted so far away form our ideals or indeed sound environmental logic!
I now want to leave the part finished build and concentrate on the house. I have felled around 40 trees, mainly chestnut and oak with odd wild cherries. The oaks are long and straight (30ft clear and straight before branches) but only around 12-16" diameter. Lots of 40ft, 4 - 10" chestnuts straight enough too.
Our land is very flat with only a 3' drop over 250' from east to west, mainly 6" soil, 12" sandy clay followed by decomposing sandstone which becomes progressively harder. 3'down is stable, 5' is rock hard although easy enough to excavate with a 3t backhoe down. deeper is just progressively harder with solid sandstone at 6'. So drainage is an issue, several days of rain leaves pools. 1" rain over 3 hours and its dry again very quickly though. Issues I have are mainly based on pole construction, probably hybrid with milled lumber where framing for windows etc. We have access to expanded clay balls, foam glass is too expensive to get to site, coming from Germany or the UK! I'm advised that gravel would not be suitable due to wicking?
So anyone have ideas for creating a dry base from natural or at least environmentally sound ones? The house is octagonal with double plane roof to create a step with clerestory windows facing NE. Lots of glass on the SE/S/SW facets, ideally 12" of SLC on the outside finished in lime based render and 8 -12"cob on the inside finished with earth/clay plaster. Ideally an earth/clay based floor with natural timber or cork in appropriate areas. Also planning to build a masonry stove and combine domestic hot water, UFH if we go down that path. We're already nicely off grid for electrical power being one of our earlier learning curves! I will also add dump load heating from our PV system to the final DHW tank.
I'm struggling with the slab insulation, it may be a good reason to buy the expanded clay balls if they will provide both a non wicking sub base and adequate insulation? Any thoughts?
All suggestions gratefully received. I'm sure I will have many more questions before very long!