Light Clay

The framing of the house created some interesting areas that were challenging to fill using straw bales, so we decided to do a little light clay instead.  In the upper level, the framing of the roof joins in with the framing of the floor, leaving a narrow wall space that widens out with the curve of the roofline, so filling this oddly shaped wall space with light clay was a great solution.

Light clay is a mixture of loose straw coated with clay slip and packed into a form.  The form is removed right away to allow for quick drying time, and there you go… a nice flat straw surface solidly held in place by the clay.

The process is fairly simple.  We spread loose straw on an old piece of plywood, mixed up some clay and water into a nice thick slip, poured it over the straw, and tossed it with a pitch fork.  We were looking for an end result of long straw that would stick together when squeezed, with no clay dripping or running off, but with the colour of the straw no longer golden.  Like a salad dressing… lightly coated.

 

We did the first foot of wall, adding screws or nails into the framing to give a little something for the straw to tuck into, and packing it in securely but not densely.  After we took the forms off, we let it dry out for a week, then did the rest of the wall up to the window bucks.  Our wall section widens out once it gets above the roof framing, but we didn’t want to fill the whole space at once and risk the centre staying moist for too long.  We put the forms back on higher up and did our second lift in another few hours.

This was the first time I had done any light clay, and I know it is another whole natural building method in it’s own right.  We have helped some friends build their house with chip slip, which is the same as light clay but uses wood chips instead.  The mixing of clay and straw has been used as an infill material for timber framed buildings from at least the 12th century in Germany and elsewhere in Europe.

It was really great to so easily utilize a variation of natural building in our predominantly straw bale house.  I think we would have done more in some of the other awkward spaces, but the timing of the summer sun was a bit late for ensuring a complete drying out of the clay slip, and we ended up making lots of small oddly shaped bales to stuff with.  But that will be another post~ the results of baling above this light clay wall and then plastering over the whole thing was quite positive.  The flatness made for a lovely plastering experience, compared to the lumpyness of the bales… but that will be another post as well!  Stay tuned as I catch up on a busy summer and fall of building.

GROUNDWORK- Building with Straw Bale

Last year we were approached about being interviewed for a short documentary about building with straw bales.  We are excited to share our story as well as our reasons for choosing straw bales and other natural materials to build with, and it is delightful to be among other home owners and builders who share the same sentiments about the homes we create.  We are currently on this journey once again, and the reminder of why we are doing this is truely valuable in the face of the various challenges that manifest during such a large and complex project.

Our wood working shop is also featured in Episode 1-Building with Cob.

Other episodes made are Episode 2- Building with Timber and Episode 4- Building with Rammed Earth.

*Made by TELUS Optik Local~ supports compelling, original stories told by filmmakers from BC and Alberta by providing production funding, training and exposure to new audiences.

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

Hand Split Cedar Roof Shakes

hand split cedar shakesBeing a splitter of cedar by trade, Colin naturally decided to split all his own shakes for the roof of his new workshop by hand.  Having many piles of cedar already collected and in need of being moved out of his old working location gave Colin a good start at the job of splitting approximately 600 square feet of coverage, or what he estimated to be 6 squares of shakes.  A square is made up of 4 bundles of shakes covering 100 square feet (each bundle covers approx. 25sq.ft. depending on length of shake and row coverage).  Using a froe and mallet, Colin split and shaped the shakes out of 18″ bolts of cedar, using the best of the shakes for the roof and saving the less than ideal (wavy, thin, less tapered, or  too narrow) for a future wall project.  froeshake splittingsplitting shakescedar shakesShakes are split by placing the froe across the grain on one end of the bolt, about 3/4″ from the edge, then hitting the froe with the mallet and peeling off the shake.  It should taper somewhat (shakes can be 24″ or 18″ long, usually the longer the better for coverage and tapering) and then you flip the bolt over and repeat the same action, flipping the bolt after splitting each shake.  stacks of shakesIt took a surprisingly long time to split the estimated amount needed, mostly because of the amount of less than perfect shakes that he was getting from the bolts he was using (of which much was old grapestakes, and other pieces of cedar that were not as usable in longer lengths anymore, as the cedar he salvages is not collected for shakes, but in longer bolts usable for furniture, gates and fencing).  Colin chose 18″ shakes partly because of the wood he had available and partly because of the curves and roundness of the roof on his shop.  layeringHe layered the shakes with an overlap of 7.5″ each row.  As the rows are applied it is important to offset the gaps between shakes from row to row.  What this means essentially is that the space between shakes never lines up directly with the gap in the row below, and better yet not for 3 rows.  The straight grains of cedar and the overlapping shakes encourages efficient water run-off, while the gaps allow for evaporation and quick drying time.  Cedar shake roofs have a life span of 50 years (though some have been known to last upwards of 80yrs).  flowing around the curvesCedar shingles differ from shakes in that they are taper sawn, thinner, and usually are rated only for 25yrs.  Cedar has excellent natural oils present in it’s wood that makes it rot resistant in it’s naturally wet climate.  Much of the northern pacific coastline, rimmed and abundant in fat old growth logs, offers ideal shake block opportunities with wide planks and tight grains.  Most shakes are collected from downed red cedars near logging clear cuts or trees not long enough to be worth milling into lumber.   roofHere we have salvaged what we can find on the beaches and then applied the best of our skills to producing by hand the beautiful and functional flow of cedar shakes.

At the very end of the project Colin ran out of suitable cedar to split for final part of the roof, and not wanting to waste anymore time as it was the middle of winter, we gave in and purchased the last few bundles of shakes needed to complete the roof.  Although a bit of a disappointment for Colin, this is the reality of building yourself, sometimes you just need to compromise and get it done!roof finishedfinished roof

Final Lime Plaster

Back in May (2011) we decided to get going on the final lime plaster of the outside of the house before the business of summer cob building took over.  Lime prefers to have cooler temperatures in which to dry, and requires much more attention to the timing of the drying process for a result of eveness of colour and trowel lines.  Much like the process of applying the cayolin clay plaster on the inside, lime needs to be troweled on continually until a whole section can be completed, otherwise an apparent line will be visible where the plaster dried too fast, or where troweling stopped.  There are techniques to make these lines look less visible if whole big sections are difficult to complete in one go at it. We added a beveled line that undulates around the house, dividing the wall into smaller sections and providing a place for us to stop.  That way we were able to plaster only the top section, and then only the bottom, and have the line of plaster meet under the bevel and so be hidden.

moving along in a team of three

Working with three people who are competent with the job is important.  Fixing spots as you go, running out of plaster when you need it, and being too late for the sponging part of plastering is stressful.  So is having the sun come out unexpectedly and not being able to stop to find a way of shading the work space.  Likewise, having lunch, snacks, and drinks being made available while working is a huge bonus in making lime plastering a smooth and fun thing to do.

getting those mixing muscles flexing

The right tools are also necessary.  We used Japanese trowels, hawks (easy to make-plywood board with a handle on one side), just like with the interior plaster, and mixed the plaster in 5 gallon buckets and then in a large tub for uniform colour and consistency.  A powerful drill with a paint mixer attached, measuring spoons and cups (depending on colour pigment used), a spatula, and big scooper are helpful to have on hand.  Ladders or scaffolding should be close by for high parts.

The ingredients are simple- hydrated lime, stucco sand, water, and colour pigment.  We soaked the lime in a big barrel a few weeks in advance.  We also did many colour samples using a one litre mix, adding pigments in increments of tablespoons to get an array of shades and colour blends.  We have many beautiful arbutus trees framing the house, and we wanted to make a colour that brought out a reflection of the deep red/orange/brown that we see in the twisting branches.  We also thought that such a colour would bring out the vibrant yellow of the yellow cedar window frames.  Red pigment, however, has pink tendencies, and so we ended up using ten tablespoons of red in a one litre mix, plus five tablespoons of chestnut brown.  Multiplying that up to 4 gallons in a bucket, and we were deep into a large quantity of pigment.  We ordered what we thought would be enough for the whole house, based on calculations for the area covered per bucket on the inside, but discovered partway through the job that we had only enough for just over half the house.  We spent way more money on colour pigment than we ever expected, but we were committed to the colour.  Lesson #1: estimating for natural plasters is difficult, and calculating for colour pigments is even more complicated.  Lesson #2: find a good source of affordable, bulk colour pigments.  Because we were pushing to get this job done while the weather was still cool, we just walked in to a concrete supply store and bought mortar pigments that come in small bags.  When we discovered just how much we would need, we didn’t want to take the time to find a different source because different pigments have different colour shades.  We would have needed to do the colour sampling all over again.  By the time we ran out and needed more though, I was very much wishing that we had.  However, in the end we spent about $800 in the final outside layer (incl. lime and sand), and compared to other forms of siding or paint, we have a beautiful plaster that soaks in to the landscape, accentuates the curves of the bales and the coziness of the forest, for probably less money in the end.

The very first thing we had to do, before any of the plaster went on, was to add the sculptural elements to the rough coat.  Elemental it was, too – the aspect of the house is situated very close to the four directions, and we wanted to acknowledge the directions and the elements on each side of the house.

south sun

We sculpted a large sun on the south side for fire, and a water lily on the west side for water.  My mom got to work on sculpting a tree on the north side for earth, and I placed two dragonflies on the east wall under the light that shines beside the front door for air.  Our beveled relief line that undulates through the middle of the wall flows through each of the elemental sculptures and adds a subtle shadow line.  The sculptures were made using the same mix as was used for the brown coat of the walls- 1 part clay, 2 parts sand, and 1 part chopped straw.  Fine sand and clay sifted free of rocks makes the plaster easier to shape.  We also wet down the wall and spread clay slip over the area to help with adhesion.

mixing lime, sand, and pigment

Lime plaster: 1 part lime, 3 parts sand.  For us, this meant 5 litres lime and 15 litres sand.  That is what we could mix in one 5 gallon bucket.  Spin it together with the mixer, and add colour pigment, mixing it in with a small amount of water.  Then we turned three buckets into the big tub and mixed them all together.  We worked out of this tub until we got low, then had our extra person work on mixing up more.

Before we started on the walls, I went around and plastered the sculptural areas first, thinking that it would make plastering the walls faster to do rather than having to do the intricacies at the same time as keeping ahead of the drying plaster.  Two were done in white, and two were done as the same colour as the walls.  What I discovered was this was not as straight forwards when it came time to do the walls.  Red pigment, as well as splatter from the rough coat of clay as it was being sprayed with water, got all over the finished sculpture and needed cleaning and touching up afterwards.  Also, it was hard to sponge the plaster without touching the already plastered areas, which made the transitions between the two look smudgy.  From a distance, it is not a big deal at all, and since this is the outside, we usually look at it from a certain distance.  So I recommend doing it all at the same time- just consider simple sculpture lines and expect to be slowed down considerably when plastering these areas.  Small tools are essential, as well as the all useful yogurt lid with the rim cut off.

sponging- making the finish texture smooth and uniform

The sponging part of the process comes when the plaster is tacky enough to leave finger prints but dry enough that no plaster comes off onto the fingers.  It can be a very precise moment, depending on the weather and how fast the plaster may be drying.  A damp sponge is simply moved around in circles to remove the troweling marks and give a smooth, uniform look to the whole wall.  Sponging too soon will pull at the plaster too much, and sponging too late means that the sponge needs to be wetter and a stronger motion is needed to smooth out the trowel marks.  A well troweled wall, however, won’t have very many marks to be eliminated.  We noticed that sponging on a too dry wall caused a variation in the colour pigment, making it a lighter shade, just like when we sponged near an already plastered spot and brushed up against it.

final plaster layer is about 1/4 inch thick

Our process went pretty smoothly.  Colin and I mixed what we needed for the day and did the troweling with a friend who pre-sprayed the wall sections ahead of us with water, sponged along behind us when the plaster was ready, and helped remix some of the plaster from the bottoms of the buckets when it began to dry out too much.  Getting familiar with the perfect consistency is learned simply through using the plaster, and noticing when it is too dry and difficult to spread or too wet and sliding off the trowel.

the art of troweling is challenged when ladders and awkward spaces need to be reached

The motion of getting it from hawk to trowel to wall is also a practiced motion that comes with repetition.  Generally, I would make lots of little overlapping rainbow swipes over a one foot square area, and then smooth the whole area down in larger swipes right away, and move on.  No putzing allowed!  Get it on, flatten it out, and move on.  Plastering a whole house gives lots of opportunity for repetitive motion learning…  start with the most hidden space and do the area around the front door last.

dragonflies at the front entrance

There are many details and considerations with lime plaster, and it is helpful if you have experience with some other form of earthen plastering, or if someone who does can give a hands-on lesson.  Again, we had the direction of Tracy Calvert, who has been building naturally since the 1980’s and has specialized in earthen plasters.  She has led many workshops and believes that skills of natural building are to be available for anyone willing to learn, like the traditional practices passed down from cultures around the world that enable the reality of shelter for everyone in a community and not only for the wealthy.

north tree

west water lily

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 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.

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