Rubble Trench Foundation for Yurt

Let's see. Today is Tuesday. We took last Thursday off and Friday morning off. We biked and we hiked – so nice! Friday afternoon, Brent dug the drainage trench so any water the gets into our trench will have a place to drain out and not become a moat (or skeeter breeding facility). We took Saturday off as we needed to be at the rental for the delivery of our new futon mattress! (To go with the frame Brent made – we'll have a bed/couch futon for the yurt.)

Sunday we hit it hard! We laid the 4" diameter flexible drainage tube (non-perforated) in the drainage trench Brent dug.  I then buried it with dirt and created a little rocked area at the outlet for it to drain on.  Then we gathered lots and lots annnnddd lots of rocks. Our friend, Bob, got in on the action delivering multiple loads of rocks he'd picked up for us. Brent used our huge 4 wheeled wheel barrow to move the rocks from the parking area to the yurt site. (The dang thing holds 10 cuft, so you really have to be careful to not overload it.) We made some incredible progress on Sunday. It was a long day and we were tired.

4" Flexible Drain Pipe

Beginnings of the rubble in the Rubble Trench Foundation

 

North side

South side

South and west side

The big rocks that you see outside of the trench will be our beefy "foundation" rocks on which the bender board and bond beam will rest (and therefore the yurt as well).  Some of those were placed before we left for the day.

Brent went up ahead of me on Monday to begin work while I took care of the domestic chores (laundry at the laundromat and some grocery shopping).  By the time I got up on site he had put together the bender board and had it resting on top of all our beefy rocks.  We worked at gathering more rocks and getting the bender board circle sitting atop them.  Scrambling back and forth to try and get the rocks level (and therefore the bender board hopefully as well) and also trying to keep a circle with a 20ft circumference on the inside of the bender board.  Monday was mostly about the big rocks and trying to keep them level among themselves. We bought some 2ft tall chicken wire that we then used to make a gabion wall - basically to help hold in place our rock foundation.  We then lay some super heavy duty landscape cloth over the top of it and packed our heavy clay soil against it - again to help beef up our foundation.  Brent used the 10# tamper to pack what I spread on the cloth and against the rubble wall.  See, to make the platform level, our north side wall rises up above the surrounding ground so we want to really stabilize it.  The landscape cloth is to keep the soil from filling in all the air gaps among the bigger rocks as that could lead to freeze/thaw issues when moisture gets in there.  The landscape cloth is thanks to our friends Bob and Ronnee-Sue.  

Gabion pre-landscape fabric.

This picture shows the chicken wire creating our gabion fence before we put the landscape fabric and then clay soil over it.

Exposed gabion on east side.

This shows some more of the uncovered gabion in the making.

 

Partially covered gabion.

The picture to the right shows the utility "ports".  We will have electric (solar), propane and water coming in.  It was easier to put them together and we chose the point closest to where the two more troublesome things are coming from (propane - not sure how long their fill hose is, we may be using tanks we can move ourselves; this site is closest to where the well is being drilled).

Here are the ports with the soil packed down around them.  We need to get some duct tape to seal them for now to keep rain and dirt out.







Brent worked up a way to help get the circle into a true circle.  He figured out how to create 8 equal pie shapes.  We knew that each full length across should be 20 feet on the inside of the bender board.  He took a straight piece of string between each adjacent point - creating an ocatagon.  He figured out what that measurement should be and we went and tweaked and tweaked until everything measured what it should.  It was a LOT of going back and forth and it was frustrating.  Getting one tweaked often caused something else to shift. 

You can kind of make out the strings in the picture to the right.  We had a tiny nail at each point and wrapped the strings on them, pulling tight.  We had some nails pop out.  The string had a bit more stretch in it than was ideal, so we had to pull pretty tight, which didn't help the little nails.  Fortunately, it held together long enough to get it into the circle we needed.  And, we found, it was not too far off level, so we didn't have to do nearly as much work in leveling it as we did it making it an actual circle.

Ideally, these would have all crossed at the exact same point, but we did get them there with tweaking (a lot of tweaking).

Next what followed was a lot of leveling and tamping.  (That fantastic leveling rake Brent is using has been loaned to us by Bob and Ronnee-Sue - super handy tool for this!)  Do you see how there is no longer a huge mound of soil in the middle of our yurt platform?  Remember I was wondering what the heck we'd do with it all?  Well, um, we are actually a bit short of dirt!  We'll have to borrow some from the piles outside of the circle in order to finish leveling the north side.  We'll also have to use some of that soil to finish filling in over our gabion walls.  The rest will be for our earthen floor.

So, as it stands now, we need to collect more rock to fill in on the south side of the trench outside of the circle.  We also need to put a small amount in a ring inside of the circle - where our bond beam will sit.  Brent is already working on the calculations for the materials we'll need for the bond beam.  We'll have to haul water in to make the cement for it as we don't have a well up there yet - soon, though!