Workshop Update

cob workshopThings have been progressing slowly but steadily in the workshop since we finally got the roof finished in the winter.

Colin focused on getting the doors in right away, refining two old doors that came from his Dad’s work of deconstructing old houses on the island, and refitting a pair of salvaged french doors.  He also built a raised stone hearth from the pile of stones we have on the property, put in the stove pipe, and wired in the rough electrical circuits.  We got the insulation in the ceiling and the plastic vapour barrier secured over that and ready for the finished ceiling layer, which we think will be some kind of bamboo or sea grass mat.

rough sculptureI spent a couple of weeks on and off getting the rough coat of plaster on the inside and outside of the building.  This layer of clay plaster is the only rough coat needed on a cob wall, and is the same layer as the third layer that we put on the strawbale house.  (See my previous post called Natural Plaster for full details).  A mix of 4 parts sand, 2 parts clay, and 1 part straw with water to mix it to a troweling consistency kept me busy in the warmer days of late winter. rough plastered windows I cleaned up and shaped the sculptural aspects of the walls so they were ready for the final layer of plaster, which Tracy and I completed earlier in May, while the temperatures were still cool enough to give the plaster time to dry.  The final clay plaster took us 2 days to put on, a seemingly record pace for any one job to be completed in.  We mixed up the kaolin clay, sand, straw, paper pulp and whiting in the buckets the day before, and then added the rice flour paste, and borax and mixed multiple buckets together the morning we started plastering.  (See my older post Final Plastering for more exact details).  We got much of the simple walls done on the first day, then completed the wall with the windows and arched shelf the next day, cleaning up our tools by the afternoon.  I am always so amazed at how quickly the finishing layer goes, compared to the time it takes to get all the other layers beneath it built.final plaster

Last weekend, Colin and I built the one interior wall that separates the workshop from a small storage room.  It will also be the wall against which will be built Colin’s work bench.  It holds the majority of the electrical outlets and is a standard 2×4 construction filled with rock wool (Roxul) insulation and covered in plywood.  final plastered windows

There is not too much left to do in this simple building for Colin to finally move in and use the space for his wood working.  Right now he is coming to the end of a giant stone facing job and is looking forwards to working with the more forgiving medium of cedar wood.  I can turn my attention to finishing the outside of the building later this summer, playing with some creative designs for sculpture as well as getting the last coat of lime plaster done when the weather begins to cool off once again.     interior wall

Cob Walls Going Up!

It has been a little difficult to keep up on a blog posting about the building of the walls, because so much is happening in such a short time that photos of progress quickly become out dated.  Most of my own time has been spent working alongside the cobbers, helping my mom to prepare and make meals, or collapsing in bed at the end of the day.  The walls are now very close to their final height, and we will soon be able to install the rafters before we continue with the cobbing up and around them.   I thought it would be a good time to review what has been done, and then follow up with the roofing later on.

We had three people from off-island join us for four days, and a continuous stream of friends and neighbors each day to learn and help out.  Colin’s mom from Florida was visiting, as well as our friends from Vancouver who sold us the property and are building the little cabin on the property.

clay slip on the foundation

We started with learning the art of foot mixing on tarps, but then moved on to using the huge pile of bobcat mixed cob.  Tracy Calvert, our cob building expert from Cobworks, showed us how to apply clay slip to the stones of the foundation to help adhere the cob to the stone, and then we started laying down the first handfuls of cob.  We focused on building up one of the wall sections that would have windows in it, so that within the four days, our cobbers would have the opportunity to set the glass in place and cob the sills and edges.  Tracy spent time each day after lunch discussing different areas of the building process, including foundations, techniques for windows and doors, plumbing and electrical, and roof structures.  On the last day, we had a small ceremony to celebrate our work together by placing objects in a jar that have a personal connection and burying it into the wall of the workshop.  We did that again with the second group of cobbers on the next weekend, and Colin and I were very touched at the honesty and words of appreciation and inspiration that everyone had regarding their experience building and learning together.  Everyone had a different reason for being here learning about cob- some of which were specific to cob and some were seeking personal empowerment.  We come together as strangers and leave each other with new friendships and new gems of knowledge to integrate into our lives.  I was reminded of the time when Colin and I traveled a lot and met different people from all sorts of paths, knowing them sometimes for a short time or a long time before parting ways, but always taking something of the experience of knowing them with me.

It is also wonderful to have friends and fellow islanders stop in for a day or more to help out.  Having the support of our community means a lot to us.  We have come to see the building of this workshop as another example of building stronger community ties with experiences of working together and deepening relationships and memories between us.

Colin and I had drawn out a general sketch for a sculptural design on the outside of two flowing lines coming out from the sides of the main door and sweeping up into a raven on the left, and diving down into the roots of a tree on the right side of the door.  We wanted to have bottles placed in the wall along the pathways of the two lines, so as we went we taped two bottles together to span the width of the wall and cobbed them in place.  We also have some circular thick glass port windows, about 8 inches across, that we wanted to have in the walls, so we put buckets that were slightly smaller than the glass in the place where we wanted the windows and them cobbed all around them.  By turning the buckets each day we ensured that they will pull out easily when we want to set the glass in.

placing corbels for the arches

We also made corbels with long lengths of straw covered in clay and layered together to build a strong protruding window sill and arches over the tops of the tall windows that we cobbed in place.  Celine, our neighbor, brought us a beautiful tall blue glass bottle that we placed in between the windows, adding more dimensions to the width of the wall.  We added a framed opening window on the east side, hammering old nails into the wooden frame for the cob around it to grab onto.  We did the same with the door bucks, creating a network of wire and nails that the cob will harden around.  There is no plumbing in the workshop, but there are a few light switches that Colin mounted near the door bucks, running an electrical conduit up to the rafters where all the wiring will run.  Other electrical outputs will be built into an interior wall that will frame in a utility room and backing for Colin’s work bench.

Trimming is a big part of cobbing.  Every day, before more cob is loaded on to the walls, the splooges that occur while building up with wet cob is trimmed off with a saw and remixed to be put back on the wall.  It is important to make sure that the walls remain plumb, so that the strength of the weight of the cob is kept directly above the foundation.  It is easy for the wall edges to wander in all directions.  It is also easier to trim excess splooging than it is to add to dips that may occur, so it is important to keep the edges as plumb as possible and allow the splooging to happen.

We had the bobcat return in the days between the first weekend of cobbing and the second, to mix more cob and to remix the leftovers as it was getting dried out.  We had two cobbers from off island join us for the second workshop, and again a continuous flow of islanders coming by and spending time working with us.

niches built into the sides of the window and bottles framing the door

By this time, we were also getting two or three groups of people stopping by every day just to see what was going on, asking questions and watching the process.  We are fairly visible to the road, so walkers would stop, cars would slow down, and our neighbor across the street sent anybody who came to see her and her road side stand over to check out our building.  After the weekend, Shawn (one of the workshop participants)  decided to stay an extra three days and keep cobbing before flying back to South Korea, and we had two more people arriving after that who were not able to make the workshop dates but wanted to learn while we were still getting it finished up.  That is where we are now- working up in the top few feet, making deadmen for the rafters to sit on, feeding Marco and Nick alongside our family, and enjoying the continued company of our community.  Cobbing so far has proved to be a lot of physical work, work that is energizing and fun with a group of people working together and learning from each other.  New creative methods of building are developed, and artistic touches are discovered.  It would be too lengthy for me to explain details of the cobbing techniques, so I will recommend a book that Tracy recommends for anyone interested in learning more.  Check out The Hand Sculpted House, by Ianto Evans, Michael Smith and Linda Smiley and Cob Cottage Company in Oregon.  I also recommend a hands on experience for a better understanding of the process, and as a way of feeling out whether cob would be the ideal method if you have a project in mind.

Cob Workshop Stone Foundation

In anticipation of our upcoming cob workshops to build Colin’s woodworking shop, we have been busy setting up the foundation and floor of the building.  The spot where we are building is tucked up against the bedrock slope that slants down and somewhat divides our land into upper and lower sections, the upper section being where we have just completed the first half of our strawbale house which will eventually be extended down the rock slope.  The workshop is situated off to the side of this slope and as close to the side line of the property as we can go.

In early July we had an excavator come and dig out 2 foot wide trenches that would hold 18 inch deep concrete footing walls with drain rock along the outside.  Colin built forms down the middle of the trench, using the clay walls as the forms on the inside of the trench and leaving the outer side empty for filling with drain rock.  We dug a connecting trench and placed a drain pipe that went down hill towards the garden.  Colin added a small grid of rebar in the bottom of the trench and then called in the cement truck to pour the footings.  He added stakes of rebar throughout the wall to tie together later after the stonework was done, as was requested by our engineer for seismic strengthening of the stone and concrete.  He also dug footings for the skylight posts and placed saddles after the concrete pour.  The concrete footing wall came up to the height of the clay grade, and provided a strong ledge onto which the excavator would place many of the massive stones that exist on our property.

So by mid July, we had the excavator back and picking huge stones from our pile that Colin directed into the spaces between the rebar stakes, trying to place them in such a way so that he could fill in between them manually with smaller stones.  He mixed and shoveled concrete as each stone was set, and adjusted the placement so that the outside edge was either flat or sloping downwards for water run off.  In the pile, he found two huge flat stones that were placed at the front double door entrance to the shop.  Then he spent the next few days picking smaller rocks and cementing them in the spaces, creating a two foot wide, irregularly stacked stone ledge two feet high onto which the cob wall will be stacked, keying in to the varying height of the stones for extra solidity between the cob and the stone wall.

A large pile of clay left from the digging of the trenches will be used as part of the clay we need for mixing the cob, and a large pile of local pit run sand is being delivered in the next few days.  Bales of straw will be picked up from the Saanich Peninsula, and a huge tarp has been strung up to protect the space from the heat of the sun as well as the unseasonal threats of rain we have been getting.  The food menu for the workshop participants is being finalized, and we have even had a friend come by to film the construction of the foundation with the idea of making a small movie of the cobbing workshops and the process of building this small natural building.

We are off in a few days to our annual family music camp, so getting as much done and in place now will help us feel more prepared when we arrive home and have cobbers showing up four days later!  We are very excited about hosting this learning opportunity, and creating a beautiful space for Colin to work in.  We are still accepting people to join us- see the previous post Cob Workshop Approved for details of the cobbing workshops in August.

Cob Workshop Approved!

Come and build a cob workshop with us! This summer we are offering an opportunity for learning about building with cob while constructing a woodworking shop on Pender Island.  Details about registering are at the end of this post.

During the last month, Colin has been working on drawing the plans for his woodworking shop that we are building this summer.  He has been using a small area in his dads workshop for a long time, and the limitations of that space are more and more apparent. Since his business ( www.thujawoodart.com) is what pays for all our land and home building projects, it was obvious to us that the next thing on the list would be a permanent space for him to expand into, with proper space for wood sorting and storage.  Since we are building within the Capital Regional District (CRD), everything we do needs to be permitted and inspected for compliance with the building codes.  Colin’s dream of building a load bearing cob workshop was thus dependent on the engineer that we have been working with throughout the construction of our strawbale house.  For the past three years, Colin has been giving him a heads-up about this plan, and sending along information and history about the processes and strengths of cob.

From Home Work, an inspiring sky lit workshop

The design that Colin has imagined was inspired by a photo in Lloyd Kahn’s book, Home Work, showing a workshop with a huge central skylight.  Colin’s design entails a large skylight, (8×12), supported by a timber frame in the center of the roof, with the posts coming down into the center of the room, and the roof rafters fanning out from the skylight to rest on the cob wall.  In this way, the walls are supporting a slightly less load than if the roof had no posts at all, and our engineer was happy to approve the designs without any other additions besides some re-bar within the stone foundation and a concrete stem wall beneath the stones for reinforcement of the foundation for seismic standards.  We sent him a video that was filmed at UBC showing a cob building built on to a seismic shaker platform, and given the equivalent shake of a 7 earthquake.  (Ask An Expert-Cob Construction).  A city engineer was witness to the demonstration, and after the building showed minimal cracking, it was subjected to a 9, at which point a wall section crumbled but the roof remained entirely intact.  Seismic qualifications are important considerations in this area, and our engineer was quite satisfied to approve our project with the information we were able to pass on to him.   We are pretty excited about this approval- there are not many engineer approved load bearing cob buildings out there yet.

a cob wall on a stone foundation

We hope that the more exposure alternative building has in the world of construction, the more it will be seen as a viable option in certain circumstances with a understandable set of guidelines and standards in place to keep the buildings safe, healthy, and affordable.  I don’t imagine that cob houses will become a “normal” way of building, but we would love to see the doors opening so that those who wish to build with cob can do so without unnecessary expense and obstacles for something that is really so easy and widely applicable.

So now,  we are organizing some cob workshops for building the cob workshop!  Here is what we are offering this summer:

camping will be in the meadow beside the swimming pond

Join Colin and Wendi, with Tracy Calvert of Cobworks, www.cobworks.com to learn and build load-bearing cob walls onto a stone foundation.  Besides covering the basics of cobbing, we will include the finer details of working around door and window frames, constructing arches and niches, using wood lintels and exploring creative bottle and glass placement designs. Discussions will provide opportunities for questions and further site specification points, as well as other aspects of natural building.  Camping sites are available in the meadow beside the swimming pond, with an outdoor shower and composting toilet. Vegetarian meals will be provided, please inform us of any special food needs ahead of time. Two positions are available for intensives covering both workshops and extra time between and/or after, as self-directed opportunities to learn more. Also, cabin facilities are possible for any needs of circumstance. It is our hope that cob and natural building construction can be widely available methods of building for a diverse, creative, and compassionate community.

the site of the future workshop will be where the pile of logs is, against the rock slope

August 10-13 (Friday to Mon. encouraged to arrive thursday night)

August 17-20 (Friday to Mon. encouraged to arrive thursday night)

Intensive including both courses and 3 days in between with extra instruction at $950 (with possibility to volunteer and stay later afterwards.)

Early bird pricing at $380 until July 27/ Aug 3, then full price of $420 after that.

Comment on this post to register, and we will be sure to email our reply.

Building A Small Cob Wall

While we have used the basic mixture for cob in many places of the house- in the floor, as rough plaster coats, and for sculpting – we have only one small wall that pays tribute to the building techniques of cob.  It is a short barrier that separates the back of the wood stove from an area that will one day be a staircase leading down to the rest of the house.  Only 8 inches wide, it does not have the usual girth of a supportive wall, and rests on a ledge of concrete that was poured with the rest of the foundation and connects to the back of the two foot tall stone hearth.  We embedded an air vent pipe that opens from the outside wall to behind the stove, allowing the stove to draw in fresh air as it burns.

We started the wall with a work party, inviting families, neighbors, and interested friends to lend a hand or foot in stomping, wheel barrowing, and shaping.  Children and cob are a perfect mix and add such a joyful presence to the job!  We used clay from our huge pile gathered for the previous plastering and floor sections, clay that originally came from a farm down the road that dug themselves a huge pond and discovered clear blue clay.  The sand is pit run sand from the island, (a silty and rough sand with lots of rocks – just fine for cobbing with) and straw leftover from the bales we got for the house.  Stomping includes mushing the mix together with your feet on a tarp, adding water as needed and rolling the mix in the tarp once in awhile to help move the bottom stuff to the top.  Inside the house, we took handfuls and pushed it into the growing ledge of the wall, using thumbs and sticks to really integrate each handful.  The work party got us up about 2 feet, at which point the weight of the cob began to cause the wall to slump out the bottom.  We let this part of the progress dry out for a day, then used a saw with large teeth cut into it to trim off the excess cob from the bottom until it measured the right width again.  We could then continue to add on to it until it began slumping again.  The lowest part of this wall reaches just over three feet, and then arches gracefully up another foot behind the hearth and the wood stove.  Then my mom got her hands in there to sculpt a draping vine along the top and dangling down the sides, smoothing out the top of the wall in a rounded curve.  After letting the wall completely dry out (about a month!)  I could finally mix up some green colour samples for the final plastering.  (See my previous post, Final Plastering, for details on mixing and applying natural clay plaster).  Working around the sculptured vine took lots of patience and forgiveness, but in the end the natural quality of the plaster reflects and brings out a beautiful ease and grace framing the hearth.

vine detail before being plastered

Final Plastering

This summer, we have finally completed the last layers of the inside wrap of the house, including all the flooring and the final coat of clay based plaster on all the walls.  This last layer of clay plaster was much more particular in recipe and in application than the rest of the rough layers, and calls for it’s own chapter in explanation.  (I have already outlined the procedure for the rough coats of plaster in a previous posting, Natural Plaster.)  I would like to express my understanding of our process in openness to the many other recipes, methods, and materials that have been used with success throughout time and in many different places.

My experience is limited to our one house here on the west coast of Canada.  However, we have also been guided by our friend Tracy Calvert who has compiled her own knowledge and experience and has willingly and generously passed it on to us throughout our journey.  The ingredients in the recipe that we used are kaolin clay, stucco sand, fine straw, whiting (calcium carbonate), paper pulp, rice flour, and a small amount of borax and white glue.  The Kaolin clay is a fine powdered porcelin clay that was purchased at a pottery supply store, as well as the whiting, which is basically a chalk filler.

We used finely chopped straw left over from baling, but we also used an alternate fiber material of bulrush down, the fluffy insides of cattail heads harvested before they turn inside out.  The sand is just fine washed stucco sand, and the rice flour is mixed with hot water and made into a glutinous paste.  We soaked newspaper overnight and then pulped it up with our paddle mixer, which we used to make the plaster in buckets.  Ratios are as follows :  6 parts sand, 4 parts clay powder, 2 parts whiting, 1 part straw, and 2 parts paper pulp, 3/4 part rice flour mix,  a handful of borax, and two or three glugs of glue.  One part for us was a 1 1/4 litre bucket.  First we dry mixed in 5 gallon buckets the sand, clay, whiting and straw, then added the paper pulp and enough water to make the mix spin easily but stiffly.

Because we were going to wait to plaster the next day, we left the mixes at this stage overnight.  When we were ready to plaster, we added the rest of the ingredients and any colour pigment we were using, then compiled three of the buckets into a big tub and mixed them thoroughly together.  This helps with consistency of ingredient quantities as well as getting the bottoms of the buckets mixed in well. For colour pigments, we did some test samples using tablespoons of pigment to 1 litre of mix, then allowed the samples to dry to the finish shade.  We then multiplied the tablespoon quantity for the amount of litres in the 5 gallon buckets (some estimating was definitely relied upon) and added that amount of tablespoons of pigment per bucket.  Finally we were ready to put it on the walls!  We sprayed the walls with water to help bond the two layers together, then considered how to plaster each section without stopping or ending up with long edges of plaster that are left a little too long and begin to dry out.  Unlike the regular clay plaster, there is only so much re-wetting that the plaster can take before it is too difficult to smoothly work new plaster up to it without leaving lines or smudgy areas.  This sensitivity to time makes considerations of temperature and air flow quite important, and usually requires two or three people working together for smooth going.  We had two of us plastering, and one person in charge of mixing up new mixes, moving ladders, bringing coffee, keeping the music flowing, and generally making it possible for us to keep working our lines until a section is done.  We spent almost five days in total plastering the whole inside of our house, which worked out to be about 1200 square feet of wall and used approx. 27 buckets of mix  (one mix being one recipe.)  We used japanese trowels, bought through the internet, and homemade hawks (rectangles of plywood with a handle on one side), as well as a few smaller tools for tight corners and edges, and yogurt lids with the rim cut off for shaping curves. Generally, we covered an area with overlapping rainbow swipes, then flattened them all down in larger sweeping motions.  We plastered over drywall as well, which we had prepared with glue and sand to provide a grippy surface.

All the kickboards and window and door trim were put in place first so that the final plaster came to meet the trim and seal any spaces.  We also tiled the sills of some of the windows before hand.  At a certain time of dryness, we went over the whole wall with a damp sponge to blur any lines and troweling marks, then at another certain point in dryness we burnished the whole wall with a yogurt lid.  This brings up the clay and pushes in any sand, and gives the plaster a certain polish that makes it more durable and smooth.

We are so happy about our earthen walls, from the clay slip through the rough coats and finally plastered with the finished layer.  I began this house knowing absolutely nothing about natural plaster, and although it took lots of work and patience, it provided a full scope of learning the art of earthen plaster.  There is always more to learn, and I look forwards to continuing on and developing my methods and skills throughout the second half of the house.  I am so very grateful to Tracy for leading us on this path and providing support as well as space for us to take it on and call it our own.  The passing on of this type of skill is important to her as we share and expand our self- sustaining abilities for building beautiful and healthy homes.

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