New user from the U.S.

[JohnB]

I would think that that was built to the Regs for a few years ago, John. It would be extremely difficult to get a pure cob walled house through the current Regs.

It was Ken. When I was there we were told it wouldn't get through the current regs, and that was quite a few years ago.

[FrY10cK]

Having lived in the cob house that I built for nine years now I can assure you that the Regs aren't the problem and that a cob house looses heat like any other structure at a rate governed by its U-value. The internal air temperature might not drop as quickly as a more lightweight structure as the thermal mass buffers the air temperature but once the heat is lost from the structure it takes an awfully long time to replace it with just "a small wood stove."

The reason that it works in the south west of the US is probably due to the higher levels and longer duration of sunlight there than in the north east. Even at low outside air temperatures sun shining through south facing glass will provide one hell of a lot of heat. The latitude difference between Arizona and New England would make a hell of a difference even without the difference in sunlight duration available.

This extra heat being input into the house over winter in the south west would counteract the night time heat losses through an uninsulated cob structure. If you take that into account it's no wonder that earthships were invented in that area and work really well there whereas they aren't so good in the UK and northern Europe: nor New England for that matter!

The earth sheltered passive solar heated design does work in the UK, see the Hockerton Housing Association houses, but they require at least 300mm of polystyrene insulation all round and a good sized south facing solar conservatory to ensure liveable temperatures. The same would be true in New England but with thicker insulation or a greater depth of earth cover.

Holy cow. There's a lot of information there that I can't take in right now because of too much beer.

But one question does arise. Why does cob work (with a small wood stove) in northern California and Oregon? The cob dwellings I stayed in were at nearly the same latitude as my location in New Hampshire, USA. I was under the impression that cob worked in Oregon but not New Hampshire because of the average annual temp difference between the Pacific and Atlantic coasts?