Blockwork Pillars

Single skin blockwork was built up last Friday. This will be used as a retainer for the concrete underpinning which will be done sometime next week. The contractor told me that they can only build this up to a certain height. The gap is then "dry filled" later. I am not quite sure what with, or why. Hopefully in a weeks time I will be enlightened.

The strongly fissured rock is also evident in this picture. There are gaps just to the left of the blockwork that you can insert your arm into ! This is oolitic limestone, and we are right on the boundary where it changes to something else. I can't remember what, but have a geology map of the area somewhere, which I will check when I find it. Limestone is a "pervious" rock i.e. it has gaps and fissures in the jointing that allow water to permeate it. The cause of this is, in fact, that it very slowly dissolves in water. Many of the watercourses have therefore migrated underground, which is why there are so many freshwater springs in this area. It also explains why very deep valleys have pathetically small rivers in them.

From our point of view it is good to be on a rocky foundation. As the Building Inspector said earlier in the week, further down-slope the ground becomes very unstable. Even in the last 10 years there has been a landslip in the field below us, and a new spring started to flow overnight. This is not something we want to happen on the site of our extension ! There was some heavy rain yesterday, and I was sure to check that none of the fissures started spewing water into our freshly dug hole !

Here is a picture of me standing at the back of the hole. This gives you some idea of the scale of the workings. The contractor remarked how much easier having the old quarry to take the spoil has made this job. If all that material had been trucked off site it would have been much slower and much more expensive.

Jan and I spent some time today pulling decent building stone from the scree slope that has been formed in the pit. A large amount is needed just to build a short section of wall, but every little bit that we can save means less we have to buy in from outside. Anway, this is genuine "local stone". We want to use at least some of it, even if just for garden walling. We strongly suspect that the house is built from it. Estate Agent rumour when we bought the house, is that the two quarries in our garden were the source of stone for the old school which is next door. As ours is supposedly the schoolmasters house, it seems reasonable that it was built at the same time, and from the same stuff.