Tuesday, August 2, 2011

Cob Cottage Company - $1,000 House workshop - 8/2010

[THIS BLOG HAS MOVED!  All posts from this one can be found at the new one, check it out! http://www.ecstatic-earth.com/ ]

Back in August of 2010 I went to a workshop at the Cob Cottage Company.  It was their three week long, comprehensive cob course, The $1,000 House.  While I was there I took more pictures than I needed to, mostly for myself, but also with the intention of sharing with others.  So here you are!  Check it out to see the full build from start to finish and get an idea of what goes on there.

So, that first picture is of the whole building, on which we built the leftmost addition, at the end of the workshop.  The right third, with the second floor loft, was phase one, the Lion’s Heart.  It bears a similar layout and design to the Heart House, which resides at the old Cob Cottage Company location in Cottage Grove, OR, and has sleeping, sitting, desking, cooking, and eating spaces.  The middle third of the building was phase two, the Lion’s Den, and has two benches and a sleeping area.  This was built as an addition, and an unplanned one at that, so there is no connection between the two spaces, just solid wall.  Now is when our workshop comes in.  The third phase, which we built on the left, is the Lion’s Paw and has cooking, eating, sitting, and desking spaces.  It was another unplanned addition, but thankfully there was a door in a usable spot, so the two single-story rooms are one unit.  Cob Cottage Company had been teaching about additions and building in phases for some time, but they hadn’t built any additions onsite until these.  Construction started on August 4th with site leveling and ended on August 27th with polishing off the roof and floors.
Here is the build from start to finish:

8/5 - Site has been leveled; foundation trench is being worked out.

Finished foundation trench and ditch draining to existing creek.

A little wet from tossing in a few buckets of water, an excellent way to test for proper drainage.

Here’s a pretty important thing: we managed to find the drain pipe in the old foundation of the Lion’s Den and tied it in to the new foundation’s drainage system with a makeshift T-joint.  If we hadn’t done this there was potential for the Den to drain into the Paw’s floor, which would be a bummer for sure.
8/6 - The foundation and drainage trenches were lined with old, worn out tarps (this is still a pretty new idea and seems to be working well.  The theory with the tarps is that they will keep out silt and other particles while allowing moisture to pass through the little holes, thus preventing clogging in the ditch; but what’s to say the tarp itself won’t get clogged and prevent the drainage ditch from doing its job?  And what happens when it disintegrates after however many years?  Should we bother?).  Next a thin layer of drain rock (1 ½” crushed and washed), then the perforated drain pipe (4” in this case, no holes on the top so silt, etc. can’t get in), then more drain rock to just below ground level.

The tarp is about to be folded over and a final thin layer of drain rock will be spread on top, still slightly below ground level.

8/7 - The first course of urbanite (broken up sidewalk chunks and what-have-you) goes down.  The first course is set almost, if not entirely, below ground level so that the foundation is properly keyed in to the ground. A second course is laid down.

8/8 - Once a decent second course was laid down we placed the uprights.  This is an experimental foundation design in which large, flat (typically urbanite) stones are set on end, tied together with tie stones, and filled with rubble and small stuff.  This design has been used on several other buildings at CCC with the belief that it may save some materials and in the end might be just as strong.  Personally, I think it looks very unstable and I don’t like it at all.  At the end of the workshop I asked one of the instructors if I should bother with upright urbanite, he said that if you have the time and resources just do it the normal way and skip the upright stuff.

A view of the inside and the tie stones on top.  You can’t tell me that’s as stable as a nice dry-stack stone wall.

The propane tank, which will fuel the stove, is going to be put on the North of the building, opposite the cooking area.  The black pipe you see is a chase for the gas line and will be buried in the floor.  The little ditch in the ground is just for access.  Also, note the hole in the foundation for the water lines to enter and exit in the same “utility box.”

Now this is a foundation.  Janis Kornouhovs demonstrates how to build a stone wall like a true Scotsman.  This foundation is for a new plaster studio addition to the tool barn and was being built ahead of time for the September workshop.

8/11 - Finally some cob!  The initial course was worked deep into the upright foundation with lots of slip on the stones to give the cob something to grip.  But there’s much more going on here:  The sub floor has been tamped and some drain rock spread out; the threshold is in place; deadmen for the door frame are about the be covered up; Donkey (one of our instructors, wearing red) has his hand on what will be the bottom of the kitchen counter’s mini-trombe wall; and datum stakes are set for the kitchen counter and desk height.
Our approximate cob mix ended up getting to be a 1:1, soil:sand ratio, with enough straw and water.  The straw and water are just things you need to get the feel for.  

8/14 - The utility box takes shape.  It’s just a basic thing to keep the floor out of the way.  Also, note how far the cob goes down into the foundation.

8/15 - The next layer of the floor is a few inches of road base.  Road base is 1 1/2” minus, unwashed.  That means as big as 1 1/2” and everything smaller, down to dirt and clay.  We applied the road base by dumping a bunch in the corner and tamping it down to the level we needed it at.  Once you have that level you can work out from it, leveling as you go, instead of trying the level multiple layers across the whole floor.  The handmade tamps were a fun experience and did the job well enough, but our instructors told us to “forget the natural stuff and just go rent a motorized tamping machine,” if you can find one, afford one, and get one to you build site, of course.  You’ll be glad you did, tamping is no fun.

This is the raised bed area in the Lion’s Den.  The log holding the drain rock and road base in was chainsawed in half and carefully stripped of its bark.  A pretty sweet set up, for sure.

This picture is actually skipping way ahead to 8/27, but it’s quite floor related.  Rosh is laying down the finish floor coat using two wood scarfs to keep things level and even.  When the section was finished he scored the edges where the scarf was and filled in the gap.  The mix we were working with was: 6 parts builder’s sand (the same stuff used in the cob mix), 1 part slip, 1/2 part horse and 1/2 part cow puckey, screened of course.
An additional final skim coat was whipped up using screened sand, and while I suppose it did make it a little smoother, it was a lot of work for not much result.

Our walls are starting to look like walls!  Things of note: road base is in and tamped, falling about 1 inch under Finished Floor Height; more deadmen for the door frame, kitchen counter, and desk are in place, all made metal-free using wooden pegs; hay bales are being used as steps and scaffolding; the kitchen counter’s mini-trombe is finished.  Who knows how effective such a small trombe wall would be, but it was a good building experience.

View from the South.

Inside view.  The finished countertop will attach right to the deadmen.

8/16 - So many people, and this isn’t all of them!

Justin Murphy shows us what a nice spine and rib on the top of your wall looks like.  We build like this at the end of each day so that it dries out quicker and the next course keys in nice and strong.  Also, note the finesse with which he trims back the wall.  Keeping you walls plumb (vertically straight) is super important while building.

A little wall-height is gained, but the focus of this picture is actually the floor.  Once your road base is done and level you should put a tarp down over the whole thing whenever you’re working over it.  Finish floor mixes should be applied once all other aspects of building are complete, even wall plastering, and all that straw and other garbage you see on the tarp would be no good for the finished floor.  Yet again, make not of how handy extra hay bales are.

Here’s an excellent process shot.  Tarps covering the tamped road base floor; various cobber’s thumbs and aeration sticks on the hay bale scaffolding; the half-buried, vertical shelf deadmen (note the pegs, shelves will attach with a triangular bracket, very adaptable); and the north wall cooler box with it’s diagonal braces to keep it square and cleats to keep it in place.

This is the rocket stove and attached bench that was built previously inside the Lion’s Den, and it is a great example of what not to do.  When building, well, any sort of building or component therein, functionality should be first priority.  While this stove does have a lovely cat-shaped bench, it doesn’t work anywhere near as well as it should.  The 6-inch system pipe diameter is too small, the radiant heat barrel is placed to high, the pipe itself is exposed (follow the line of the level to the bottom edge of the shadow on the floor, see that light spot?  The result is a cold bench and a dangerous hot spot), and the entire exhaust tube goes through the floor and snakes through a bench on the opposite wall (disperses heat into the floor which is unnecessary due to the passive solar heating).

Here is that bench opposite the rocket stove.  Gettin' a little close to having too much pipe.  This bench would probably take a huge amount of time to heat up.  The thin wall surrounding the pipe is made out of adobes that Donkey brought in for us.  Just give them a good coat of slip and maybe some cob mortar and that’s it!  A thin, 1-inch layer of cob was put over the outside as well.

8/18 – The bench is filled with rubble and gravel and is capped off!

This would be a window buck built for the Lion’s Den.  Two six-pane windows would later be installed.  Gaps on the side will be filled in with cob, then plaster.

Big progress on the walls, more deadmen in place, Vicky and Bill’s sweet niche next to the front door.  The scaffolding in place was incredibly stable, versatile, easy to make and can be any height you need!  Also, note the Lion Den’s ridge beam sticking out from the right.  It was later cut off at the wall and a hole was dug in the existing wall for the new ridge beam to sit in.

The South view.  Note the finished mini-trombe wall and the seemingly skinny, but totally fine pillar in the middle.

Vicki's little SW-facing window in the desking area will light up the corner towards the end of the day, but not blind you with direct sunlight.

The desking corner, deadmen for the desk surface, outlet for a lamp or whatever, closed little niche in the upper-right wall, and the prior little window in the upper-left wall.  Wiring that outlet was very informational in its initial install, but also when we had to dig it out and install a new one after it was cut with a cob saw no less than five minutes after we received very specific instructions to “mind your wiring when cutting through a wall.”

8/20 – Lots of good stuff going on here: walls are at finished height, doorway and lintel are complete, lintel over S/SE windows is done, and the ridge beam is in.  Note the wiring running along the ridge beam: the electricity was just spliced off of the Lion’s Den and the wire would be tucked under the ridge beam later.

An outside view of Jim and Pablo's sweet corner work on that S/SE window lintel.

The North wall cooler, all cobbed in.  Those diagonal braces will stay in there until the wall is totally dry and settled.

8/25 – The SE side of the Lion’s Den with its new coat of rice hull plaster.  Rice hulls are a great substitute for short-chopped straw in your rough/scratch coat plaster.  It was super easy to apply and sculpt, too.  Finer finish plasters would be applied over this.

A detail shot of the little lip we put around the urbanite.

The plastered interior of the Lion’s Den.  The Paw was still way too wet for plastering when we were through building.  This plaster mix was a supposed “one coat wonder” that could function as a scratch coat and finish plaster.  The end results were little cracks all over the wall (which you can see a little over on the right) and uneven wall surfaces (as seen on the left).  When doing your own house, just take the time and do a couple coats with nicer stuff.

The roof is on!  The ridge beam and rafters (all shaved roundwood) are on, the wall was built up a little on the right to meet the roof, the bender boards (thin flexible off-cuts from lumber production, most mills have them and will be glad to give them to you for free or cheap) are tacked down to the rafters so that they look nice on the inside (they don’t do any actual protecting in the whole scheme of the roof), and some hay bales are built up into a super handy staircase for access to the roof.

The untrimmed edge of the roof over the S/SE windows.

The top edges of the wall are packed with cob to seal against the roof, and the shelves are finally being used!  Note how bright it is even without any light and warm colored plasters on the walls yet.

Some sweet little shelves and windows doing their job quite well!

More untrimmed roof: note the curved mini shoulder beam.

The West wall with its tiny windows.

Another little shoulder beam was set in the wall on the NW end so that we could get the proper curve and overhang on the roof.

The North wall of the Lion’s Den with its rice hull plaster.  Note the stove exhaust pipe buried directly in the wall (perfectly fine!).

Here’s a good example of working with what you’ve got: the Lion Den’s North wall is bale-cob, that is, made largely of straw bales due to their insulating nature.  One of those bales was sticking out quite a lot, so rather than trying to cut it back or fill in the huge gap, we just accentuated it and made it look intentional.

8/29 – It’s all done! Or at least finished for our workshop…  The hundreds, even thousand year old cedar threshold (harvested from a fallen tree, of course) will probably last for just as long.

The finished edge of the roof received its “EPDM” (it’s actually just a 5 mil sheet of plastic, a far cry from a pond liner), yet we didn’t have time to sod the roof.  The window panes are also tacked in place with some block of wood.

The ancient cedar windowsill took just a little trimming and fit right in!

It looks like a real house!  And check out those walls: so plumb!

Check out how the two roofs were blended together.  That swath of plaster to the right of the door was a test for a finish plaster, though I’m not sure about the mix.  I think it was something like: some screened horse manure and however much clay slip seems good.

The future cooking space: wraparound counter, handy electrical outlet, utility box in easy reach.

The finished North wall with its desking nook, cooler, and bookshelf.

Again, our finished building on the left and the two prior building phases in the middle and on the right.

I've got a full video walkthrough of the Lion’s Paw as it stood at the end of our workshop that I will post eventually (it's a huge file and is going to take many many hours).  I'll post it on it's own and replace this when it's up.
Prior to the workshop I had wondered if I really needed to go to Cob Cottage Company or if I could just go and do it right now (having only read their book, The Hand-Sculpted House, and a few others like it).  I felt confident and I’m sure I would have made something that was pretty safe and good looking, but getting to go practice first out there was invaluable.  Yet, a huge amount of hands-on building experience isn’t the only thing you get at one of these workshops.  If you really pay attention, Cob Cottage Company also teaches you how to live in your home once you’re done.  That’s something that’s a little harder to convey in a book.  The food you'll eat will be the best you've ever had and the people you'll be with will be your new family.  If you’re into this stuff, as you should be, and can manage it you should certainly go spend some time with these people.  It’ll do you a lifetime of good.
On a side note, I would like to eventually rewrite my workshop notes into a more organized form to share with everyone, as there are a lot of things in there that have changed since The Hand-Sculpted House came out or were never in there in the first place (especially Rocket Stove notes!).  No idea when this will happen, but it’ll be on here.


  1. Adam, that is amazing!! Please email again when you add more. You are always onto something interesting. Thanks for keeping me in the loop! -Marci

  2. this is so sweet. Are you going to build one Adam?

  3. Thanks so much Adam for posting this! Brings back great memories from that workshop. Hopefully we will get our hands dirty soon.

  4. this is wicked cool, and your documentation is incredible. nice work. the lines are so smooth and cool, i really cant believe you did this in such a short time!

  5. thank you for the step by step...this has really helped me to see how to begin the process.
    big love.
    Joanna Summers


Note: Only a member of this blog may post a comment.