The Adobe Floor is complete!

Wow, it was a hot week to be lugging around heavy stuff, but the adobe floor is in, leveled, and drying!  A rough calculation shows that I moved around 8,800 pounds of materials, with a little help!  Actually, we moved it twice: once to add the clay, sand, water and straw to the mortar mixer, and a second time to wheel barrow the completed batches into place.  Enjoy the photos:

The first day's progress: four batches.  What's that in the lower right of the adobe?

Cat Prints!  The curious neighborhood feline that likes to visit my barn evidently wanted to see how solid the new adobe material was.  Answer--not very!  Come back in a couple weeks and  it will feel like concrete.

Day two was slow because of all the plumbing penetrations

Moving along on day three, also showing a few tools of the trade.

On day four, a Wednesday, there is hope that I'll finish on Friday and be able to enjoy my Saturday.

And on day five, it's looking like I'll finish easily  tomorrow.

And the payoff... Finished!

It even looks like the photos in the books!

Adobe Floor Preparations

There are several layers that need to be installed before I can start with the adobe:

Four inches of pea gravel.  The discoloration is due to the gravel being slightly damp from the previous day's rain.  Note the hand tamper: that was a lot more work than I'd anticipated.  If the space had been bigger, I probably would have considered renting a gas-powered tamper.

The next layer up is the 6 mil polyethylene vapor barrier.  However, before I installed that, I pre-fit the first layer of foam (1-inch thick) and cut holes for the pipe penetrations.  This photo shows how I used the foam as a template to know where to cut the vapor barrier for the pipes.

With the poly in place and stapled up the wall, I taped the vapor barrier around the pipes using Zip Tape.  I don't have a picture, but the corners are folded like Christmas wrapping but on the inside.  Since the goal is to make the poly as air-tight as possible, it's better to avoid cutting: hence the corner folds.

This shows the second layer of 2" foam in place at the other group of pipes.  At R-5 per inch, this provides a total of R-15 under the radiant slab.

Practically done:  The joints have been taped, and spray foam has been added around the pipe penetrations.  The last thing to do is glue the side foam panels down and tape the side joints.  It was only a matter of a couple hours until the first load of adobe mix was flopped down and leveled.  More on that next....

Light Straw Clay is DONE

It's drying nicely this week with dry temps in the 80s'.  The rule of thumb is to allow one one week of dry time for every inch of LSC.  In my case, that's 3.5 weeks.  So worst case, I should be ready to close in the walls on 9/21.  My test sections have dried in less than 3 weeks.  (I weighed them every day and when the weight leveled off, it's clear that they were dry.)

I can already feel a different climate inside during the heat of the day: it's noticeably cooler compared to shady areas outside the house.  Thermal mass at work!   Here are the finished interior walls:

East wall.  (I'll give you one guess which corner the bathroom is in)

South wall.  Note the plywood outside the left window: that's my rain screen, which keeps the LSC dry in rainstorms, while still allowing the wall to breathe and dry on clear days.

West Wall.  You can see some areas of pea gravel aren't 100% dry yet.  The pea gravel is the drainage layer and leveling course below the adobe floor.

North wall.  Passive solar design says to minimize window area on the northern exposure.  

Ready for Rain

With a bunch of rain in the forecast, on Thursday I screwed temporary 4-foot high plywood sheathing to the outside of the framing.  This should keep the worst of the rain off the light straw clay.  It's not the end of the world if it gets slightly wet as long as it doesn't get totally soaked.  With the top half of the wall left open and the 8" between the plywood and the LSC, there will be plenty of air flow, so I can leave the sheathing on for days or weeks at a time while the LSC continues to dry out.

Also notice the big pile of pea gravel on the left side of the shot.  First thing next week, most of that gets moved inside as the base for the adobe floor.

Nearing the end of the Light Straw Clay

There hasn't been any dramatic progress this week, buy it's nice that almost all the light straw clay infill has been completed.  There is just a little more work to do to fill in the quarter-rounds around the windows and then it's on to the adobe floor.

West wall: the only thing left are the quarter rounds at the door and the little panels above the rough opening.

This shows the mold I made my cutting out a section of 12" sonotube and screwing it on to 1x4 poplar boards.  The poplar gets screwed onto the framing and it is filled from the outside.

Not the clearest shot, but it shows how the plywood form is screwed onto the framing at a diagonal and filled from the outside.  The 1x3 diagonal bracing is muddying this particular shot.

Shot showing both quarter rounds in place.  I can't wait to see what it looks like with plaster on the rounded parts!

Three contractors at once

The other day entailed a massive amount of simultaneous activity!

In addition to the three of us working on Light Straw Clay infill,

The plumbers roughed in all the drains under the floor, and

The roofers installed the shingles and corrugated metal roof.

I'm still a little sad that the roof isn't green, but the "light stone" color is so much better at reflecting summer heat, that energy efficiency won out.

Filling up the walls

After getting through the learning curve at the workshop, the speed at which we're placing the Light Straw Clay has gone up significantly.  

Day two saw us nearly complete the entire north wall, which has the largest volume of LSC.

Turning the corner into the east wall.

Mixing the straw and the clay slip on the ground was rather tiring at the workshop!  With 2 or three people mixing, that was a reasonable solution, but with only one person mixing, this 3' x 8' table with a tarp tacked to the wall makes for a much more ergonomic experience.