[Cob] Some off-the-cuff ideas

[Dognyard]

Recently, we had installed a cistern on our acreage to replace our old
bored well that was slowly caving in - not to mention that recent years
of lowered rainfall has dropped the water table - making our well almost
useless for household use (bottom rising up, water level dropping down).
Any way, we thought we could still use the well as our means of watering
plants, etc. We have an old pressure tank we no longer use, so we
decided to build a pump house to surround and protect the old well as
well as to protect the pressure tank. We will use it in the warmer
months, then drain off the tank and shut it down for the winter. Because
it will only have seasonal use, insulation in the pump house is largely unnecessary.

I have started the small 6' x 6' pump house - thinking I could pretty
much build it from scrap lumber and leftovers from other projects. We
did not put in a foundation of any kind, but rather used four deck
spikes (one at each corner) with four 4 x 4 posts (one at each corner),
then decked the floor. I will be framing in between these 4 x 4s to
build the walls. I have yet to decide what I'll use for siding on the
pump house (thought I would see if I can scrounge some nice old barn
board or something from a farm, etc.).

I haven't built the roof structure yet, and it occurred to me that
although I can't do a cob pump house (speed was a bit of a factor here),
perhaps I could do one cob wall. I would have to put in a bit of a
foundation, then I could key it into the framing along one outside wall.
I could then build the roof with ample overhang to shelter the cob wall,
and the cob wall would be on the lee side of the prevail weather systems
anyway, so it wouldn't tend to get pummeled too often in bad weather.
Later, I thought I could build a small deck on that (the cob wall) side
and just enjoy sitting next to it :-).

I know that the pump house, with it's footing of deck spikes, and the
cob wall - which would have a rock footing, would move differently from
each other. They would be tied together, but may shift or move
independently of one another creating some cracking over time. Or it's
possible that since the cob wall would be significantly heavier than the
rest of the pump house, maybe I'll get lucky and the cob wall will just
pull the pump hose down to it's level if the footing ever move. Not an
ideal situation, I know, but it may afford me a small way to play with
the cob.

An alternative to tying the two walls together, is to just lean the cob
against the pump house. As the cob dried, there would likely result a
very small gap between the two walls. That is, don't key the cob to the 
wall at all? I will have an old recycled window in that wall, so if I
don't key the cob to the wood wall, I will still have to leave a window
opening in the cob.

Which would you choose? Key it in? Or just cob against the wall but do
not key it in?

Karen in Alberta