I expect the shelter to become very air-tight. Or at least the ambition is to get it as tight as possible for good temperature control. The only really critical part, where cold air might blow in uncontrolled is the door. But if I buy a ready manufactured door, it should become really tight.
However, it would be desirable to have the possibility to open for some controlled fresh air intake, in particular when the rocket stove is running.
Therefore, I have now integrated an air-intake channel in the cob wall. The channel should give me the possibility to open for some controlled air flow into the shelter. The direction of flow should simply be driven by the draft of the rocket stove.
I got 3 minor pieces of a flexible plastic pipe in a useful diameter from a dump container. I just had to piece them together using a few cable ties.
I have placed the channel with the intake to the west facade to take the air directly under the roof overhang. The tube then runs along the wall, but strictly downwards to release the air about 15 cm above the floor at the northern wall inside. If condensation water would develop, it would run downwards into the shelter and could here be collected in a little container. However, in winter time, the air in the tube would most likely warm up on the way through the intake channel in the cob wall. And therefore I do not really expect much condensation to occur.
At first I hesitated a bit to place the pipe along the wall. I was afraid this may compromise the walls stability. But after having ‘cobbed‘ the pipe in, I feel that the pipe may even improve the strength, because of the direction of the reinforcement by the straw, which – I imagine – after pushing the straw with the rod, will be placed needly and snuggly in the corrugated outer structure of the pipe.
After day 1.
And after day 2.
Last not least, the status quo