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.

Water Storage and Irrigation System

A small deck and arbour disguises the concrete cistern which collects our spring water, and provides a beautiful space from which to enjoy the pond. The hand pump allows us to access water if the power is out.

Water is a precious resource on the Southern Gulf Islands… and figuring out how to manage what we have when we have it is integral for everyone.  The water source for our three acres of land is supplied by a spring, which has been a registered water source since the 1950’s.  It comes out underground from fissures through the bedrock slope that we have built our house on, and it is beleived that the main supply is filled by rain water running off of George Hill, which rises to the north of our property.  While the land had been only mildly developed, the source of the spring was dug and pooled into a gravel bed and directed to a small concrete cistern.  Previous owners added a small water pump and plastic 300 gallon tank for their domestic use, which serviced the trailer that we became residents of when we purchased the land.

2009- pond dug and water cistern going in

The spring flows all year, but has seasonal fluctuations of flow which correspond quite directly to local rain fall.  It slows to a trickle during the dry season, and fills up again within a few weeks of our first fall rains.  So we have a huge abundance of water in the winter, but we still have to be careful not to overtax the storage capacity in the summer.  With more gardens being created, and more water facilities in the house up and running, we needed to amend our water system to include more water storage.

We added a 1200 gallon buried concrete cistern at the time that we dug the pond, in 2009.  Our field is solid clay, and so was horrifically wet all winter and the pond helped to redirect the incoming winter moisture.  The concrete cistern overflows into the pond, which overflows towards the garden.  However, the water level of the pond drops below the outfall in June, and so the spilling waterway dries up in the season when we could use it the most.  As the next 6 years went along, we watered the garden by hand (which got to be a bigger and bigger job) and experienced  a few summers of extended hot dry conditions, which proved difficult for the spring. Last April we addressed this by adding 2 plastic above ground tanks, each holding 2,000 gallons, for the prupose of irrigation.  The summer following was another long and dry season, but we had awesome results with keeping plants well watered through drip lines and mulch, using the water we set aside from the spring.  We had to refill them partly in August, setting the refill flow at a slow trickle overnight.  By the time the rains returned in october, our season of growing was less intense and we could turn off the irrigation.

 

Here is a water map of our system as it is functioning at this time.

  1. Underground spring collects into gravel bed and perforated pipe, then gravity feeds to fill the cistern.
  2. Buried concrete cistern holds 1200 gallons, and overflows into the pond.
  3. Water pump in the shop draws water up to the house for our domestic supply.
  4. Water goes through a UV filter.
  5. Outside house tap is turned on to fill the two above ground cisterns using the filtered spring water. (2000 gallons each)

The water is then fed by gravity into the irrigation lines.  A 1″ hose heads to the orchard, where it is split into a 3/4″ line that continues around the pond, and into a 1/2″ line that runs through the orchard.  Drip hoses with either 6″or 12″ spaced drip holes irrigate the rows of cordon espalier fruit trees, and into the various flower, herb, and berry beds.  The veggie garden system is similar, with various drip lines coming off the 1/2″ line.  We dug the 3/4″ line shallowly into the ground around the pond as well as burying the 1/2″ line in places where it crossed paths to avoid damage from stepping on it or tripping.  Two timers are attached to the lines leading into the orchard and leading into the veggie garden, since each area has differing water needs, and shut off valves are placed at the major forks to allow us to manually open or close each section.

The drip system was fairly straight forwards to install after a lesson from islander John Eckfeldt who supplied us with the system.  It is fairly flexible and configurations are easy to adapt for year to year changes.  It works well with a gravity feed, although it is usually affixed to a pressurized system.  Our large tanks are uphill from the gardens by a small degree, so we did some drip tests to see if the volume of water coming from one drip hole was the same as the product indicated, as well as testing out a length of drip line to see if the drip rate was the same after 20 feet.  The timers we bought are also intended to work with less pressure such as gravity provides.

 

 

 

Framing~ The Bones

roofDespite a very frigid December (for the west coast), we managed to continue building just in time to get the roof sealed up and water tight before the wet west coast winter starts in.  Here is a brief account of the structure of the frame, and the way in which we are going to insert the straw bales.

first wallOur decision to use a stick frame method as opposed to a timber frame (as we did for our first house) was mostly a compromise of time and money.  Stick framing is super fast, and we hired an experienced framer friend (thanks Danny!) to work with Colin and his design with the curved roof lines.  Dan helped Colin put his drawings into a model of the house in Sketch-Up, a computer program for architecture, so they could get accurate measurements for all the framing, especially where the lengths of the 2×4’s change subtly with the curves.  The curved roof was the main reason to use stick framing- it was eaiser and faster to frame the studs under the curved beam which is essentially two 2×8’s (cut out of 2×10’s to get the curve) overlapping all along as one continuous header the length of the roof- this also alleviates the need for headers over doors and windows.  Framing started on December 2, and was done in a month, despite a week break over Christmas.  We still have some interior shear walls to frame, as we were focused on the walls that were necessary for the roof.  Also, window and door framing will be cut in sometime in the spring.  Many people have asked us about how 2×4’s can be the only thing holding up a living roof, but the engineer says they are strong enough with the 3×8 beam on top.

The exterior walls are framed to 18 inch centres, as we will be standing the bales on end between the 2×4’s.  A lengthwise notch will be cut down each side of the bales to fit them snug around the framing, and thus hide the wood frame down the centre of the wall of bales.  The new international building code for straw bales has published findings that the bales placed 14 inches wide in the wall is the same insulation value as their 18 inch wide option, due mostly to the orientation of the straw.

All of our interior walls are shear walls (plywood on one side, and attached to the foundation directly), as required by the engineer, since our exterior walls are straw bales and not considered to have any shear strength.  The shear strength is the load that an object is able to withstand in a direction parallel to the face of the material, as opposed to perpendicular to the surface.  In walls, it is usually plywood or cross bracing that provides the shear strength, preventing any side to side movement.  So our internal walls are (or will be) sheeted with plywood and continue down to the foundation.  At the foundation, the walls are secured with hold downs to resist any upwards movement in an earthquake.

The roof is standard construction with 2×4 strapping over 2×12 joists, though in the more curvy parts of the roof we had to use double layers of 1×4.  On top of the strapping is standard 1/2″ plywood decking and a 4″ curb all around the edge to keep the dirt in.  We decided to go with a double layer torch on roof membrane this time, which should easily last a very long time, longer than us… The roof was torched on in early January and we are now secure and dry for the rest of the winter.  Colin is back to work in his shop for the next few months to get caught up with his ThujaWoodArt projects, but come the spring we hope to do the infloor heating and plumbing under the concrete slab on grade subfloor, and prepare for installing the straw bales in the summer.  We will be offering workshops for installing the straw bales and plastering in the summer through the local Heartwood Folk School, check their website for more info as we get closer!

Phase 2- Continuing the Build

foundationFoundationThe basis on which something stands or is supported; a base.  The basis or groundwork of anything.  An underlying basis or principle for something.

An overview–  The previous straw bale house chronicled on this blog was the first section of two parts of our whole building plan.  The first half is designed as an in-law suite for my mother, with a shared art studio space, and this second half that we are just starting will be bedrooms for us and our kids and a garden level living space.  The 3 acres that we have contains a lower open feild where the pond and gardens are situated, a forested upper area, and a sloping face of bedrock in between.  Since we don’t want to clear the forest or use up valuable growing space, we have designed the house to be built on the rock.  The first half sits at the top and overlooks the pond and gardens, and the other half is separeated into two floors, each built like a terrace from the garden level up to the existing section and attached with an enclosed walk way.  The total square footage will be about 2,000 square feet.

excavatorWe are building with as much attention to natural materials as possible.  We are using sustainably sourced or salvaged resources whenever we can.  The walls in this half will be straw bale with clay and lime plasters, with a living roof, just as in the first half.  We are aware of the imprint of building houses these days and the huge amount of toxic off gasing that occurs with many conventional materials as well as the chemically saturated waste that ends up in the landfill.  However, since we are building within the boundaries of building codes and needing to meet the requirements of engineers, architects and inspectors, there are just some things we can’t avoid.  Natural building can be a tag that is placed on our house as a whole, but I think it is important to state that not every aspect of the house is “natural”.  Such as, for example, the foundation.

The second half-  There are not many places in Canada where you could begin to build a house in November.  Of course, we didn’t plan to start at this point, but the process of aquiring the permit took longer than we expected.  We learned from our previous build that everything will take longer than expected.  Amazingly, the weather has been quite co-operative, allowing us to complete the form work in one week, and giving us the sunniest day of the month on the day we scheduled the pumper truck.

There is not much about the foundation that would fall into the “natural” category.  We hired an excavator to dig the footprint, and rented a large rock drill with a giant, gas powered compressor to drill out 140 holes in the bedrock, each ranging from 16″ to 24″ deep and filled with concrete grout and rebar.  We purchased a lot of 2×10 and 2×4 lumber as well as some plywood for the forms that we hope to re-use again in the framing if possible.  We set five runs of rebar inside the length of the footings and stem walls with a 1′ grid of rebar in the higher walls and snap ties every 2 feet, and placed knockouts of pvc in the footings wherever we need drainage, septic, and water runs.  We hired a concrete pumper truck and 3 truck loads of concrete.  We set anchor bolts every 3 feet in the top of the concrete to attach the framing.  The engineer is happy, the geo-tech is happy, the building inspector is happy.  This is not terribly extraordinary in the world of regular construction, in fact it is quite standard and even a “small” job.  To me it seems rather complex, requiring a lot of effort and money to create forms that become deconstucted and a structure that is largely unseen in the end.

However, this crucial first step is the foundation upon which we will begin to build up our visions of a beautiful, healthy, comfortable, sustainably functioning and lovingly hand built family house.   

 

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