The Joy Of Concrete

I love concrete and I’d like to use more of it. This love developed at architecture school which was riddled with Corbusian inspired modernist teachers. The professor there, when I was studying, was Andy MacMillan who worked for a company called Gillespie, Kidd and Coia. Here is some of their work: http://www.gillespiekiddandcoia.com/ .This was during the dark days of post mordernism when lime green greek columns were a serious proposition. Google ‘brutalist architecture’ images for more concrete porn. A house I designed in Dunsborough, WA, has some neo-brutalism and that can be seen on my website.

Unfortunately, due to cost constraints, we don’t have that opportunity here so this is the best concrete update I can give you. On Monday the concreter came to site and dug all the ground beam trenches, these are so that concrete beams can be poured that will sit under the slab and support the slab and walls. When we did the bulk excavation at the back garden earlier in the month we dug down 200mm below the finished ground level so that the soil from the ground beam trenches could build the finished level up again. This was a good idea and saved us some work but we underestimated how much more soil would come out when the ground beams were dug out and we will have to wheelbarrow more soil of the site. Below is a photo showing the ground beam trenches. It also shows a 50mm layer of sand that sits above the soil and that will be under the polythene plastic that will form the waterproof membrane. Also below is a photo the following day showing the waterproof membrane and the reinforcing steel that gives tensile strength to the slab (concrete is strong in compression, steele is strong in tension). The steel is supported off the ground by plastic spacers so that the steel is in the slab rather than at the surface of the slab where it could corrode. These are seen as the black discs under the steel. The concrete is trucked to the site and pumped to the back of the house. The concrete floor is then smoothed, levelled and toughened by being ‘floated’. This is when the concrete us rubbed, in this case it is power floated with a machine but it can be burnished by hand to give a more natural finish. One of my favourite floor finishes is when black pigment is added to concrete and it is then hand burnished. This can give an effect like black semi gloss leather. In our case the floor will be battened out and recycled floorboards will go over the surface.

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