The house finally got its first layer of skin yesterday, thus marking the beginning of the longest milestone. The third and final coat of render will not be applied till all the internal fit-out is complete, which we estimate to be late winter/early spring.
To say that this past week has been hard is an understatement. Thankfully everything went smoothly on the day, and all the hard work was worth it all, especially for the view of the house from the driveway. As the Grand Design peeps love to say: “it blends into the environment”, and for once Matty and I seem to think so too!
Prior to the render going on, all the timber frames, lintels, posts, top and bottom boxing had to be covered by mesh and then stuffed with straw; bondcrete also had to be applied to any other exposed timber areas that couldn’t be meshed. These two processes were to ensure that the render sticks to it and also creates a marriage between the two surfaces (the timber and the straw), so that the render can bind to both. The meshing and straw stuffing is monotonous work, but thankfully Sam and Benny Boy came to the rescue and helped unburden some of Matty’s workload.
We hired a professional (Mark) who specialises in rendering strawbale buildings; Matty had met him at the strawbale workshop he attended last April, and thought it wise to use his services.
Five people (inclusive of Matty and myself) worked for over eight hours yesterday, completing the inside and the outside strawbale walls of the house. Mark used a render pump, essentially something similar to a concrete pump that pumps out render onto the walls; the render mix is made on site whilst the pump is going.
The natural render mix consisted of the following ratio of ingredients: 75% sand, 15% clay and 10% lime. We had to do test patches with various ratios about a week before to ensure that the render will not crumble after drying. The first coat should also crack a little once set, which is a sign that it has bonded well to the walls. The consecutive coats of render will have increased amounts of lime and less amounts of clay.
The clay in the mix is the bonding ingredient, and helps the mixture stick to the strawbale walls. The lime hardens the mixture, and the sand is the showstopper. The colour, texture and quality of sand is what gives the house its final colour, unless of course you want to add an oxide which is purely there for aesthetic purposes. I was initially pro oxide use, but now that I see the somewhat finished effect, I have changed my mind and want to go all au naturale. This is Matty’s preferred option for two reasons: 1) the oxide mix cannot guarantee that the finished colour of the render will match expectations 2) oxides are very costly and will definitely blow our budget.
The second coat of render will take two days to complete, this is because it will be about 30 mm thick compared to the 10 mm thickness of the first coat. Mark and the render gang are due to meet again for the second coat in a fortnight from now, giving the first coat ample time to dry and set properly.
The house currently looks a bit like play-doh, lumpy with straps and mesh sticking out. We will fill the uneven surfaces with cob and staple the mesh in to ensure a flatter surface between now and the next round. Nonetheless, Matty and I are proud parents, patiently waiting to see the house blossom after its awkward teenage phase.