Sculptural Walls

The wonderful thing about natural plaster, whether it be on a cob wall or on straw bale walls, is the potential for creative sculpture. Cob is even more so, as 3-D shaping can be accentuated into the depth of the wall, while with straw bale, the sculpture tends to be more on the surface (unless one wants to cut into the bales). In the bedrooms and the hallway, we added some sculptural elements before applying the final plaster.

In the hallway, we had rather lumpy bales, which I managed to make less lumpy with the rough coats of plaster, but there still were definite hills. Either side of the opening that leads to the upper level of the house were really rather bulgy because of the small cavity within the framing that we rather awkwardly stuffed mini-bales into. We decided to build up a kind of crossing of flowing ribbonish lines that would frame the sides of the opening and go up and over the arch we had built at the top. These lines also widened out around the staircase landing, and down the length of the hallway. We drew lines on the wall with chalk and then used water and some clay slip to moisten the wall before beginning to add the cob.

In the bedrooms, each of the kids wanted to design and create their own sculptures, so we have a bird above one window, and a tree in the corner of the other room. We built a small half moon shaped shelf in our room that is wide enough to hold a tea light candle.

The sculptures look so much more effective when the final plaster is done, but that will have to be another post! The additions of the sculptures definitely makes the work of the final plaster a lot slower and more tedious, but in the end, having these personal touches of creativity enhances the intimacy of the house. Too much sculpture, I think, can be visually overwhelming, so finding a balance between a nice smoothly finished wall and a specific placement of sculptural detail is good to consider. However, considering how much work it is to build a house in the first place, I think it is equally important to take the creative opportunities when they arise- and cob/natural plaster is a wonderful way to incorporate such creative moments.

Ceiling Layers

Getting the ceiling finished was the next important step, allowing for lights to be turned on so we could work past daylight hours, and enabling us to finish the walls with the final plaster. We were also keen to get the insulation above our heads as soon as possible, since the cold space of the addition was effecting our heating abilities in the finished part.

We did the same as before, adding 10 inches of rock wool insulation in two layers- R14 and then R22, giving us a total value of R36 above our heads. Since the strawbale walls are somewhere around R35-40, it made sense to match that in the ceiling, even though it is way above code for this area, is twice as much work to install, and ups the cost of the insulation dramatically. We did the same in the first build and are incredibly happy with the heating and cooling effect of the high insulation.

Because of the changing angles of the rafters, pieces needed to be cut on varying matching angles to stay held in place. It is not a pleasant job, with the configuring of ladders and the rub of insulation across one’s head and face, but at least the rock wool is less irritating than fibreglass, and eventually it gets done and then it’s… done!!

Covering the whole ceiling with the vapour barrier afterwards is way better as a two person job. Crinkled and oddly stapled plastic is just annoying.

We had acquired (for a fairly cheap price) 5inch wide tongue and groove cedar in 10 foot lengths, which needed to be stained previous to being installed- we used a natural product called Osmo which is a Geman product of natural oils and waxes. The wood is quite varied in colour tone and has a fair amount of knots, but none the less is a beautiful material to use and the oil stain made it even more brilliant in tone. Because our rafters run the width of the house (15feet) but curve the length of the space (40 feet) we needed to put strapping across the rafters so the ceiling boards could go up in the same direction as the rafters. Initailly we thought we could find ceiling material that would flex a bit with the curve, and so run lengthwise, but without incurring the high cost of custom milling something thin enough to bend, we had to change plans.

We had round LED lights to set into the ceiling, and of course other required things like the bathroom fan, stove fan, and smoke detectors to work around. Having the ceilings done really changed the whole space!

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.

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