16th June 2014
Having set the drains in place and laid down the polystyrene heave protection, the guys on site are now pursuing the meticulous task of knitting together all the steel bars that will take the strain within the slab once the house is built upon it.
Men of steel knitting - I do like a mixed metaphor. The completed steel mesh does indeed look like knitting thanks to the little loops that hold the bars together. The steels that come out of the top of the piles also have to be bent down into the mesh. Likewise the steel U-bars that go under the drainage channels must now be connected to the underside of the mesh, as the drains run under the slab but must not move relative to it.
It all seems like a lot of engineering for a modest two-and-a-bit storey timber-frame house. Nonetheless it is reassuring to know that the house will stay up regardless of what happens beneath it. Although there are thousands of Victorian houses in London built on little more than a few courses of bricks, they are vulnerable to drought and changes in the water table. Over the course of the coming century, the changing climate is likely to keep underpinning contractors busy.
It is strangely quiet on site. After all the piling and digging and muck shifting, preparing steels is more like a fine craft. Greg and Mark have to concentrate and get into the groove. In, over, through and out.