Cob Rubble Trench Foundation & Water Drainage

Hello,

Wondering if anyone can give me some advice on an issue with the rubble trench foundations for cob. I'm planning to build a cob house with 3 rooms total. I am a public school teacher so I only have summers off to work, so I'm planning to build one room at a time over the next 3 years. (with some weekend time for minor work) Anyways, here's a simple drawing of what I'm wanting to build with color coding to assist my question...

If I build one room at a time, will it matter if the pink wall areas have drainage pipes laid in the rubble trench since they will ultimately be interior only walls? I do realize that these (pink) walls will be exposed to the exterior for 1 or 2 years before the whole thing is complete and will need drainage to protect the structural integrity of the cob. If I lay in drainage pipes under all the walls (pink and yellow), after all three rooms are built, will it matter that drainage water will be running underneath the (pink) floor walls inside the house?

Anyone with experience have some advice on how to go about this?
Thanks so much!

Hi Rose,

You'll probably get a lot of different opinions about this, but I personally only install drainage pipes on the outside perimeter of the structure if at all. I prefer to trench and fill the drainage, sloping away from the home and terminating in a French drain, but in some climates you may need the pipe in order to move large amounts of water.

Check out the raised earth foundations thread for more info.

All Blessings,
Bill