First Plaster Layers

With the baling done by September, our goal was to get the first layer of plaster on the bales before the winter rains began.  Plastering has to be done while the weather is still suitable for quick drying, since it is not advisable to have wet clay against the straw for long enough to develop mould.  The faster it dries, the better.  Because it was September when we started, we decided to make this first layer no thicker than 1/2 inch.  If it had been June, we would have taken the seasonal opportunity to fill the dips, which would mean much thicker plaster in some areas.  However, we will probably go around in the spring and add plaster just to the places that are dippy, so the next layer will begin to smooth out the surface of the walls.

Once the baling was done, there commenced the job of stuffing.  This entails going over each wall and looking for spaces that push through the bales, generally where one bale meets up against another bale.  All along the tops of the bales needed stuffing, and sometimes where the framing separates the bales.  Tucking in tight little twists of straw to fill these places becomes methodical but doesn’t take too much time.

After that, comes the messy job of applying clay slip to all exposed straw.  We collected waste clay trimmings from a pottery studio, and soaked it in buckets so it becomes soft and scoopable.  Then we mixed it with more water to dilute it to a thick chocolate milk consistency, using a paddle mixer.  It was thick enough to not drip very much off a dip stick.  I created a little wearable square bucket to hold the slip while I slapped it on the bales with a big brush and a gloved hand.  The bucket, equipped with old belts that went over my shoulders, could catch any excessive dripping and free up both my hands to massage the slip onto the straw.  It dries a much lighter colour of pink.

Then came plastering!  We used local clay from an excavation job on the island, pitt run sand, (also from the island) and all that straw we collected from the bale trimming.  We built a soaker pit from damaged straw bales, lining it with tarps and then filling it with clay and water to make it soft.  On tarps, we mixed 4 or 5 shovels of the soaked clay with 10 shovels of sand by rolling the tarps around and then foot mixing, adding water as we went to get a good consistency without allowing the mix to be sloppy.  Adding a few handfuls of straw (equivalent to 2 or 3 shovels)  soaked up a bit of water, so sometimes we would add a bit more if it became too stiff.  The test is to make a ball, and not have it ooze or slop, but also not have it be too stiff and crumbly.  The other test often comes from actually applying it, and becoming used to the ideal consistency while working with it.  The hands on experience of plastering generally becomes the best way to really learn!  We had to adjust things as we went- our ratios changed as we dug into our clay pile and found less high quality clay.  We noticed that our mixes were more silty, difficult to apply, and orange in hue instead of blue/grey.  It was a subtle change as we filled the soaker pit, but after a few mixes we realized we needed to amend our clay from a different pile we had saved.  (After so many years of natural building, we have all sorts of little and big piles of resources hanging around!)

The clay slip gets sprayed with water before applying the plaster, just lightly, not so that water runs down the wall but the slip turns darker in colour.  A handful of plaster is then smeared onto the wall with the heel of the hand, and massaged in so that it doesn’t peel back off.  Everyone finds their own method, but the important thing is that it isn’t too thick, or too thin, ideally the same thickness, and it doesn’t peel off! Our first group of plasterers were my son’s school class, a group of 24 kids ages 10-14.  They spent a whole day rotating in groups between mixing, plastering, and hiking around our part of the island while birding and geo-caching.  They got so much done!  We also had a visitor staying with us for two weeks, learning all the steps of plastering.  For the next month, we had a variety of friends and community people coming by for a few hours or a day to get their hands muddy on our walls.

Partially dried wall

We focused first on the north walls, and the places where there is less sunlight and wind movement.  Then we moved to the inside when the weather got rainier in October.  Luckily, the fall was generally sunny late into November, so when we finally got to the south walls, the warm sun was still shining most days.  We used a fan to help dry out some of the inside walls that weren’t getting much sun.

plaster over clay slip with insulation at the top covered with metal lath

Plastering the bales in this build was different than the last house we did because the bales were oriented differently- instead of placed like bricks and plastering the sides of the bales we have stood the bales up and plastering the faces of the bales, where the strings are.  In the last build, we trimmed the entire bale walls, shaping the curves of the windows and removing any shaggy straw, so the plaster went onto the evenly cut ends of the straw.  This time, we couldn’t do any trimming because of the baling twine, and the plaster went onto the length of the straw.  While we didn’t need to take the extra step of trimming, it was a little more challenging to apply the plaster.  The walls are more lumpy and will need some extra work in the plastering to get a nice smooth wall.  Smooth walls, of course, are a matter of aesthetic preference over function.  Maybe in the end we will incorporate more creative sculptural elements into our walls.

first coat plastered dried. Burlap will be plastered into the next layer of plaster.

This winter will be a time for these seed ideas to take root while the house building projects are on hold.  We can take some time to sit in the house and imagine the different possibilities for the next phases.  It can be frustrating at times to have to be patient, but often the results come with better decisions and a renewed sense of creativity following the flurry of building.

If you read all this and want to see more photos and more descriptions of plastering, please refer to my previous post on the last house we did~ Natural Plaster

Building Straw Bales Walls

The last two weeks of August kept us busy as we were finally ready to place the straw bales into the walls of our house.  This was a completely different process from the first part of the house that we completed in 2013, in which we stacked the bales like bricks around a traditional timber frame.  This time we constructed a regular stud frame to support the roof, placing the stud’s on 16″ centers to accommodate the width of the bales in between the studs.  The stud wall effectively disappeared as the bales were placed between them and stacked up end to end to the ceiling.  At the base of the walls were toe-ups which the bales would sit on- filled with drain rock and rigid insulation (which also included some rough electrical).

The straw bales were reported to be 18″ wide, 36″ long and 14″ deep.  However, as we discovered when we got them, they were more like 19 or 20″ wide, which didn’t work too well with our framing.  So we set up two stations where the bales were cut before we could place them.  The first was an electric chain saw placed in an Alaskan mill device so the chain saw could slide easily across the edge of a bale at a set height.  Then the bale would get notched~ a second station in which a jig holding a grinder with a chain saw blade would carve a 4″ wide notch down the center of each side of the bale.

If we needed any specific length bales to fit into smaller spaces, which happened all along the tops of each wall, we would manually resize the bales first, then send them to station number one.  Eventually a system of tagging the bales with their length, as well as having a written order of the needed sizes on a piece of paper meant that when they were ready to go into the walls, we could just refer to the paper and the tags to put them in from one side to the other.  To make mini bales, baling needles, baling twine and a measuring tape are needed.  Thread the needles with twine, poke them through the bale at the needed length and in the same place as the original twine, pull one end of each through and then wrap the other end around the bale to tie them together… tightly!  Then cut the original twine.  Save those pieces for making other smaller bales.

An integral piece of equipment for getting the bales in was the CRAZY CARPET!!  It was quite difficult to shove the bales in, as we had to place the bale in against the open stud, place a crazy carpet against the straw of the bale on the other side, force the width through to the other side of the stud, then remove the crazy carpet.  Depending on the density of the bale, we had stakes to push with, mallets to slam with, and 2×4 scraps to persuade with.  Depending on the height, we could karate kick or shoulder check them as well.  The higher bales proved more difficult as we were working on ladders.  We had to be systematic in working right to left, (or left to right) along a wall as shoving a bale into a space with bales on both sides was pretty much impossible.  This meant that we had to be prepared with all the odd bales as we went~ we couldn’t just place all the easy ones first!  It also meant that things slowed a little sometimes while custom bales were made.

We inadvertently made a lot of cut straw byproduct.  The chain saw station produced 9 large garbage bags and two large mountains of 2 inch straw pieces.  The notching station made 5 large garbage bags of finely chopped straw.  We kept the piles separate, as the longer straw will be perfect for the first two coats of plaster, and the fine straw will be great for the final plaster.

The whole process called for continual creative problem solving.  The stud framing made for some very awkward spaces, especially around window bucks and in the corners.  We sized the window bucks to glass that we already have, otherwise we may have changed the sizes to fit evenly between the studs.  We ended up making a lot of 8″ or smaller bales and flipped them lengthwise in the spaces.  The corners also had a lot of these small bales stacked up, and we placed extra 2×4’s to hold them in place on the outside, and also to secure expanded metal lath around the outside corners so we could hand stuff those areas with loose straw.  We considered making forms and stuffing the corners with light clay, but the lateness of the season made us worried that the clay might not dry fast enough.  We will apply the clay plaster right over the metal lath, which is secured to the wall using zip ties attached to the baling twine of the bales in place.

The other awkward area is where the bale walls meet the main rafter on the south and north walls.  The rafter is made of two 2×10’s cut into a curve and joined together, and arches over the center of the bales, above the stud’s.  The bales come in underneath this rafter, leaving a 10″ space before the soffits and interior ceiling.  We cut strips of insulation and fit it on either side of the rafter, and used the metal lath to cover it and join in the with bales, so the plaster will extend up to the roof over the lath.

We ordered 350 straw bales from the Saanich Peninsula last August (2016) which is a mere 20km away.  Optimistically, we hoped we could get them in that fall- however, as our time line stretched into the winter, we resorted to storing them under a large tarp until the spring, when we moved them into the house in June after we completed the concrete slab floor.  There were many damaged bales, and after a huge sorting process of fully damaged, partially damaged, mildly damaged and good as gold, we ended up with about 250 in various piles.  We estimated that we might have needed to purchase up to 25 more, but in the end, we used every last one that was deemed good enough right to the last space.  Luckily, our enthusiastic gardening community purchased our damaged bales for their gardens.

So many of our friends came out and helped with the process during the two weeks that it took to get all the bales in.  It is always so humbling to have community members take time out of their own busy lives to volunteer for an afternoon or a day of slamming bales into our walls, or tying up smaller bales, or running the grinder or chainsaw.  The swimming pond became the ultimate spot for breaks, and many great conversations and smiles and eating of fresh fruit filled up the moments between hard work.  It truly made the daunting task of building our walls so incredibly enjoyable.  Thank you again to everyone who helped out!  We feel so supported and blessed.

Sub-layers of the Floor

Getting the sub-floor completed adds a whole new level of progress, allowing the next stages of the build to continue with greater ease.  The main floor of our straw bale addition went from an 18″ deep mucky clay hole to a finished concrete surface that we can directly lay the final tile floor on.  Here is an outline of the different layers and the process of putting them in.

1.First we filled the bottom with 6″ of gravel to cover the 4″ drain tile that runs under the house (as we are on a hillside with many springs weeping from the bedrock) and will allow any water that gets under the house to drain away easily.

2.Preliminary plumbing- all the plumbing is laid out across the floors and supported by the drain rock to create a slope across the main floor towards the septic.  The bathroom, utility room and kitchen water fixtures all come together into one 4″ main drain that exits to the east where it will end up in a septic tank/lift pump to take up to our existing septic field.

3.Insulation layer- placed directly onto the drain rock, we used whole bags of perlite that we laid out tightly side by side and gently flattened (by foot) to create a solid layer of 8″ insulation, which gives a R value of 25.  We chose to use perlite because it is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. (Rigid foam insulation is the usual building material for this use, but it is made of polystyrene.)  In some places we had to customize the bags by emptying them partially to help fill the spaces which were not the same shape as the bags.  Here is a link to the Perlite Institute which has complete information on using perlite for construction insulation below slabs – https://www.perlite.org/library-perlite-info/insulation-perlite/Perlite-underslab-insulation.pdf

4.On top of the perlite bags we put 2″ of sand, filling the spaces around the bags and then compacted the whole floor.

5.The next layer we put down on top of the sand was the 6mil construction poly vapor barrier and then laid out the metal rebar mesh that would be pulled up into the 4″ slab.

6.And the last thing we had to do before pouring the slab was attach the hydronic infloor heating Pex tubing to the metal mesh.  It is best to consult someone about the layout and spacing of your tubing as it will greatly affect the heating potential of your hydronic system.  It is also important to use sleeves to cover the Pex tubing where ever it comes up through the slab.

7.Once everything was ready we ordered the cement and Colin worked with a crew of 3 others to pour the slab in less than 3 hours.  The slab is flat, but not super finished as we will be putting 12″ mexican tiles down as the finish floor surface on the lower floor of the house.

The upstairs currently has a plywood subfloor.  We haven’t yet decided what we are going to use to finish it.

bathroom- exposed is the box with water lines for the bathtub, as well as venting and drain openings

 

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.

Straw Bale House Building Work Party

NATURAL BUILDING WORK PARTY!  Learning opportunities for straw baling, light clay, and plastering starting now and continuing throughout September for our straw bale addition on Pender Island, BC.

It has been a rather unpredictable summer in terms of our building schedule, but we are finally at the point of putting the straw bales into the walls of our house.  These things just always take longer, right??  We started off on Monday, August 21 with an enthusiastic group, gathering in the morning to check out the partial solar eclipse that was visible from this part of the continent, and then spending the rest of the day getting the order of operations sorted out.

Our method of placing the bales standing up in the columns created by the stud frame is different from what we did for the other half of the house, which was a timber frame structure with the straw bales stacked like bricks and secured with exterior vertical bamboo.

We would like to invite everyone who is interested in experiencing building with straw bales to come for a few hours, or a few days, to take part in a variety of jobs which will shift over the next few weeks as the work progresses.  From this point onwards, there will be many tasks to complete, and while it will be difficult to schedule the type of work being done over this next time period, we would like to offer a general list of natural building components that we will be looking for help with:

  • trimming, notching, sizing, and stacking bales
  • stuffing
  • light clay- we will be filling some areas
  • clay slipping all the wall surfaces
  • mixing and applying the first coat of plaster

light clay- filling the forms

Give us a shout and let us know when you can come and we will try our best to let you know what we will be doing.  Or, let us know what you want to do, and we will contact you when that job will be happening as soon as we know.  Things will be much quicker depending on the amount of help we have, but realistically, we also have to consider the cooling of the days as we get into the plastering part of things.  The plaster needs to dry completely within a certain time frame… same for the light clay.

trimming and notching bales

This week, August 23 – 25, and August 27-31, we will be working to fill the walls and we are looking for extra help.  Anyone that is interested in learning a different way of building with straw bale is welcome!    We also have a lovely pond for swimming and will be providing snacks.  If you are from off island, please send us a note of your interest and we can provide more details.

Weaving for a Collaborative Art Show

The local winery here on Pender Island offers their large tasting room to local artists each weekend of the summer for art shows, and this summer I was invited to add my weaving to a group of four artists- painter (and my mother!) Margaret Alpen, photographers Eve Pollard and Derek Applegarth, and glass jeweller Nancy Westall.  The room at Sea Star Vineyards is open and bright, with lots of wall space and a large, plank style table in the centre.  It was wonderful to have so much room in which to display scarves and ponchos, rather than trying to fit everything in on a market table!  I also really enjoyed seeing my designs blend with the work of the other artists.  The colours of Nancy’s jewelry really matched beautifully, and Eve had a photograph that she took of my and Rosie.  Also my mother’s west coast arbutus trees and forest paintings created a wonderful sense of place.

I was inspired to focus mainly on pieces in which I had incorporated my hand spun angora fibre from my angora rabbit, Rosie.  I have been spinning it in a blend with other fibres, mostly merino and alpaca, and the pure white result is refreshing to weave with.  Having a few display mannequins really helped to show the shape of the ponchos, which were the pieces that sold the best!  This was my first art show, and it was lovely to chat with the folks that came by, and show them my Saori loom which I brought along to set up.

Another nice touch is the Winery’s request for the artists to donate to a local non-profit organization in lieu of rent for the space.

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.

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