Putting the lid on
There are lots of different options for roofs detailed in the earthship books. The main point to all of them is to catch water for use in the house. This means the roof has to be non-porous and covered in a material that won't leach noxious substances into the water. They also have to be well insulated.
We've decided to go for brai/bitumen because we like the organic look to these roofs. This will have to be painted to stop it leaching chemicals into the water.
The roof of the round room will be a geodesic dome which we would ideally like to tile. This picks up on the Moorish architectural style seen in Andalucia.
As you can see from the blog entries to the left, this process started in December 2007. A fully insulated, waterproofed roof to the main area was finished in July 2011. There have been other jobs in between, and we only work an average of one day a week on this project, even so, I would say the roof involved a lot more work than the tyre work, mainly carpentry and wood preparation.
See below for a summary or the menu to the left for more details in our blog.
Stages of the roof build - main flat roof
First there was the bond beam to secure on top of the tyres, this acts as a brace between the tyres and the roof. Then we put in the pillars and beams. And lastly, filled in between with cans and concrete up to finished ceiling height.
The front face of the greenhouse was fitted with more beams on top. Once this was finished we could then put the ceiling planks on. Then we had a bit of a blip in proceedings, due to being in an earthquake zone, we had to put extra strengthening between the greenhouse and main section beams to get it passed for building regs. The brackets are the rather ugly solution. Eventually we got back to building the cricket on the ceiling planks.
Having chosen to use cork pieces rather than rigid insulation we needed to build a rigid structure to hold them. We used the same wood as the ceiling planks for this as well as for the skylights. The cork pieces were poured in and then covered with plywood. Then we made sure all the vents, pipes and chimney were in position.
Now came the backbreaking work of berming up to the roof top, finishing with a sieved and raked layer ready for the plastic sheet. We painted on 2 layers of bitumen gloop. Then put on the bitumen sheet and painted this with a hard wearing plasticated terrace paint. This all overlaps onto the berm sand and is edged with bitumen covered sand bags to take the second stage berm.
Another layer of sand was put on top of the plastic before the final stage berm earth was dumped on and raked flat-ish. Sandbags and soil were shaped around the west edge of the roof to direct the catch water into the storage tank. The first stage catch water filter system of varying grades of rock is our next job...
Click here to read a summary of the work on the geodesic dome.