New wall with the new year

I formed this up after Christmas and poured the two last days of the year. It had been cold and frozen for weeks, putting this concrete work on hold. Luckily it warmed up and I got just a long enough window of about three days to pour and most importantly, cure the concrete. I went to the site New Year's morning to cover and insulate the wall, it was going to get cold again that day and I didn't want it to freeze too soon. I covered it with plastic and a lot of straw.

Kitchen Framing

Here is my working plan for the kitchen framing at this point. More to come soon.

Kitchen 'Crete

After months of scheming, planning, and mostly being occupied by other responsibilities at work, I've finally begun actual work on the outdoor kitchen at Oxmoor Farm. Last Friday with the help of Kitty and Adam, I poured the footing for the foundation repair.




You can see that the foundation rests on bedrock, which is limestone here in central KY. The channels and holes in the stone were created by both water and plants. Limestone is primarily calcium carbonate and is soluble in slightly acid conditions, such as groundwater. I had to root out three large honeysuckle bushes that had grown out of the foundation, and were likely the cause of it's damage. The roots twined down the channels you can see in the picture and dove down through tiny cracks in the stone, secreting organic acids which dissolve the limestone and allow the plants to absorb the minerals.


Securing the forms was a little challenging because the extra thin topsoil made it impossible to drive stakes in the ground. I had to brace the forms with the dirt I excavated, and luckily it was enough support.



The straight form boards left gaps between themselves and the bedrock which I filled with stone and packed soil outside the form to prevent concrete seepage. I also installed a drainage system towards the inside of the wall to get rid of water that may build up inside the wall.


Here are Kitty and Adam, helping with the pour while I ran the mixer.



After the concrete was placed, I let it cure for a few hours and touched it up with a steel trowel. I stuck in some rebar, roughed up the surface to adhere to the next pour, scratched the date in a section that will be exposed, and covered it with plastic and straw because the forecast called for freezing temperatures. Concrete can't be allowed to freeze for some time after it's poured, but I think it will be ok because it's in contact with the ground which hasn't frozen, the curing of concrete is an exothermic chemical reaction which creates heat, and it's covered in insulation. Stay tuned, I hope to complete the concrete work this week, if the weather get's out of the 20's! (it should be in the 40s by weeks' end)

cob oven

I haven't posted in over a year, so I suppose an update is due. I've done some building since my last posts, although I don't have pictures of much. I worked on the foundation and framing of a strawbale building in rural Kentucky, did some residential remodeling, and re-plastered the strawbale at Bonnaroo. One thing I have pictures of is the cob oven I built this summer on a farm. It's my first one and I'm pretty happy with how it turned out. It functions really well, and I've enjoyed a number of great meals with elementary school students, who visit the farm on field trips. Best pizza in Louisville.


The oven is at the site of my next project, the outdoor kitchen at the Food Literacy Project, located on historic Oxmoor Farm in Louisville, Kentucky. The materials for the oven were completely free. I salvaged the lumber from an abandoned arbor. The clay and stone were taken from the site. gravel and sand were found in small piles outside a barn, covered in a few years growth of pokeweed and thistle. I used loose straw from the barn floor in the cob and dried grass in the plaster. The fire brick was taken from an earlier attempt at an earthen oven that was built a few years ago and never really worked. Metal roofing and screws were donated by home depot, along with 6 bags of quickrete, but didn't end up using it. I tamped the posts in gravel to facilitate drainage.

I am about to begin building a post and beam outdoor kitchen on an old foundation about 6 yards from the oven, I'll upload some pictures soon.

Cob Cottage Update

Cob lends itself to massive walls and curved forms. The space it creates feels radically different from what most of us are used to, yet it's so familiar and seems more sheltering. You can't tell from a photo, but the quality of light that passes through a thick wall is also quite different...notice the soft curves and illumination of the window reveals.

On a technicial note, the shelves on the left of the photo hadn't been installed when this picture was taken but you can see the roundwood buried in the wall they will attach to. This methold of attachment was used all over the cottage with the windows, door frame, and roof framing all being anchored by such "deadmen". Also note what the mud daubers left while the building was open and drying for the summer, quite fitting for a mud building!

I traveled back to Chapel Hill in September to help Greg coordinate the finish plaster and pour the earthen floor. We did the interior plaster in one day with a few volunteers, then the floor, and the exterior plaster the next weekend. It was a very busy week and we got a lot accomplished.

Our plaster was a mix of local clay slip (a thick suspension of nearly pure clay in water), sand, and horse manure. The ratios were something like 1:2:1/2 respectively by volume, but don't obsess over numbers. You go by feel more than anything else and your local materials are certainly quite different. An earthen plaster should be very sandy or it will likely crack. It should not feel too sticky but should hold together in your hand. The horse manure was added for tensile strength, as it is pretty much completely fiber.

A properly finished earthen floor is hard and durable, but we decided that a partial brick floor near the door and stove would be appropriate. Aside from functioning as a sort of landing and hearth space the brick added visual and textural interest while complimenting the stone nicely.

 


Our mud hut even has electricity!

 


Pouring the earthen floor.




We mixed our material in a wheelbarrow with a hoe, although for a job of much larger size I would use a mortar mixer. We carried the mix in buckets, spread it on the subfloor and troweled the surface flat. The floor received much subsequent hard troweling as it dried over the next few days.


Greg with the last of the mix.



Once fully dry, after maybe 6 weeks, a treatment of linseed oil and beeswax will serve to harden and waterproof the floor.

Catskill strawbale

Here are some pictures of a more conventional strawbale building, to serve as a contrast to the one at Bonnaroo. I worked as a subcontractor on the bale work in December of last year.


trimmed straw, ready for plaster




trimming the bales flush




A jig for ripping bales with a chainsaw

Piedmont cob

Here are some photos of a cottage I built with my friend Greg in Chapel Hill, North Carolina this spring




The building is set on a south slope for maximum solar gain and it's slightly burmed into the hill, which will help to moderate temperature. We built on a rubble trench which combines drainage and footing functions.




The blank slate. Most of our stones were local igneous bedrock. Others are quartzite and sandstone leftover from building the client's house years ago.




It took a few days to set the first course of stones and the threshold. After that our speed increased dramatically as we went along.






Greg









I played when I needed a break. I learned a whole lot about stone (and these stones in particular) by fooling with them. The foundation benefeted from it.




This was a dry foundation (no mortar!) and I tested every stone to make sure they didn't move



Greg and I taught a couple of cob workshops during the building process. Here we are mixing cob by foot.





Industrial cob alternative




Cob is composed of clayey subsoil, sand, straw and water. It's mixed to a firm yet malleable consistency and walls are built handfull at a time.
















We built the rafters right into the cob walls which made building a curvy roof quite easy. The framing is achored to deadmen (usually pieces of strong forked roundwood) that are buried in cob.










Except for the lumber all the living roof materials were salvaged. Here were are filling the truck with dumpstered goodies.




Green roof workshop








Here you can see the strawbales. The west and north walls are a bale/cob hybrid for greater insulation.




It's not done yet but looking good! We still need to install the woodstove and door, plaster the walls, and pour an earthen floor.