We just finished applying a hot lime wash to our ‘Ty Twt‘ building in Wales. Here you can see the finished building.
Ty Twt is a load bearing straw bale house completed by my company, Hartwyn using our intern building model. The house was completed in 11 weeks in 2016, with a final weekend to finish up the lime and green roof just completed in July 2017. Continue reading
Jake, one of my 2016 Interns, has been busy updating his website to show the major steps from the build.
His latest post is on the subject or dropping the roof and compressing the straw bales.
Thermofloc is a natural floor insulation. Made from cellulose that has added minerals to make it fire retardant. It is simple to install and is much more affordable than any other natural insulation we found.
To break apart the insulation blocks we used a double whisk mortar mixer. By using an online calculator to work out how much we needed for our floor dimensions, we could be sure to achieve the correct density and therefore U-value.
NaturePlus – Thermofloc is the first cellulose insulation to be awarded the coveted NaturePlus mark of quality and sustainability.
- Laid density of 40kg/m3
- Thermal conductivity 0.039W/mK
- Fire classification as per EN13501-1
- Free of hazardous substances as defined by ETA-05-0186
Assessments show Thermofloc does not provide a suitable habitat for rodents and as such rodents will avoid nesting within the insulation.
Around our windows we have posts, so we need to put a notch in our bales to fit them snugly.
We do this using a Dewalt Alligator saw which is made for cutting building blocks, wood, drywall, insulation and Class 12 clay blocks. It also cuts straw bale very nicely, without throwing up a lot of dust.
I have also used a chainsaw to do this job. While the chainsaw does do an excellent job, it’s certainly more dangerous and a lot louder, plus throws dust into the air.
Here interns, Brendan and Rowena show us how it’s done using a template to ensure the right size notch. (Music by Money Mark)
Here we see our beautifully constructed straw bale walls. In front of them, two of the tools of the trade.
First up, we have the persuader. This larger than life hammer is used to knock the bales into alignment.
Secondly, we have the baling needle. This is threaded with twine and passed through the bales like a giant knitting needle in order to re-string the bales to custom sizes.
The first thing we do to our bales is to dress them. This means we physically manipulate the straw in the end of the bale to make a flat and square end. This means our bales fit together better with fewer air gaps.
Long overdue group shot of our fantastic natural building interns!
Introducing (From the left): Me, Brendan, Rowena, Blythe, Jake & Jamie.
This is the team doing the bulk of the work. They have given up 8 weeks of their lives to come and build this house. I’m so very proud of how far they have come and what they have created.
We are now getting into finishing land, so i’m really excited to unleash them on the clay and trowels!
It is important to us to build with locally sourced materials. We have lots of clay, so are utilising that as much as possible. If this build were elsewhere in the country we would be choosing a different approach. We can’t just have a template for a ‘sustainable home’ that doesn’t factor in what local materials are available as transportation accounts for a huge amount of energy usage.
These are our obvious success stories….
We have not been able to source everything locally, our smartply for example, came from the Czech Republic. Not great!
There have been other more subtle design choices that have allowed us to use more local materials. An example of this is how we have sheeted the roof. The conventional way is to use 18mm ply sheets, usually shipped across the country, if not Europe. We have opted to use larch planks from our local saw mill – It takes longer to build, but the environmental impact is far better.
http://www.sustainablebuild.co.uk/locallysustainablematerials.html
This is our natural building intern, Jake’s take on Car tyre Foundations building.
Car Tyre foundation, a great way to build strong sturdy pillars, reusing a waste material & without concrete.
The technique goes a bit like this;
Items needed: Lump hammer, crowbar, plank of wood (same width as tyre), level, pair of gloves.
http://www.buildthechange.info/blog/2016/10/2/car-tyres-foundation
This week we have been laying our car tyre foundations for our #BalesInWales cabin.
We have chosen to use gabion basket foundations. Though our Gabion baskets are reclaimed car tyres.
This last week we have been happily filling our car tyres in neat stacks, here is intern, Jamie showing us how it’s done!
Foundations Video from JeffreyTheNaturalBuilder on Vimeo.
The load bearing straw bale will be finished externally with lime render and chestnut shakes and roofed with a sedum green roof. Internally it will be plastered using the clay dug on site, and has a composting toilet, greywater treatment and solar hot water heater. Continue reading
