The first use of a mechanical digger was for the sewer trenches.
Originally the house would have had an outside privy in a shed in the garden,
in the 60's when the bathroom was added to the back of the house and mains water reached the village,
the sewers led to a septic tank beside the house and then drained into the garden.
Some time in the 70's mains drainage was connected, the septic tank filled in and the sewer was routed directly to the sewer in the street.
The problem for us was that the route the sewer took would be underneath the new extension. Although the
architects had intended to leave it in place and provide access to the inspection chambers under the
living room floor, we decided it would be better to re-route the whole thing clear of the house.
This image shows the digger driver's view of the trench after about 10 minutes. (Shortly before we dug up the water main and the old gas line !).
We started round at the front, the clay subsoil had to be carted away to a skip in the road one wheel
barrow load at a time, we became fairly adept at dumping a bucket load of muck straight into the barrow.
At the rear we put in a new inpection chamber to connect up next door's pipe which runs into ours.
In the end we left the existing sewer in place until the last minute and there was olny one afternoon when our
neighbours were without any drainage.
The biggest problem in planning the layout was to get the gradient correct. We measured the depth (or invert) of the existing pipes with an improvised water level made with the garden hose and couple of pieces of clear polythene tubing. Then we drew a scale drawing and set out marks for the digger that were 1.2m above the level we wanted at each end of the trench.
There is a lot of head scratching and calculation to extrapolate the height correctly from the corners out to the
marker posts that have to be clear of the digger.
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