Phase II sits on top of phase Ia, the bit under the cloth in the illustration of 27th May and the bit to the left of the olde shed base in that of 16th June. By way of a shutter, I reused the by now rather split plank which had served for phase Ia, with some cunning additions underneath to make a snug fit and held in place by a sturdy piece of 8 by 2 at each end.
But not sturdy enough as as I started to fill the shutter with concrete, the top of the front plank moved up, the bottom moved out and I did not notice until it was too late to push it back into place and secure it there. I did not fancy digging out the wet concrete and starting again, so I secured it as best I could with lumps of masonry which happened to be lying about and finished the thing off. More or less OK but the front of the sill was well off vertical (although at least it was sloping away, towards the fence) and there were some voids at the bottom where the concrete had not been properly compacted into the void left by the moving shutter, partly because I was scared of it moving even more. Furthermore, when the front of the shutter moved, it came adrift from the chipboard divider, the front of which is now covered by a thin skim of concrete. I suppose I ought to hack it off but I'm scared of making a bit of a mess. We will see how things look when I have filled the voids. Will I pass muster as a concrete finisher, a trade all to itself during my days as a concrete tester?
In any event, the phase II beam was finished off nicely with a layer of pea gravel between it and the fence. All very smart. A wheeze which will not, sadly, do to cover up the olde shed base.
Phase III runs along the base of the west wall of the garage, where the tools are stood up in the illustration of 27th May and the bit to the back of the olde shed base in that of 16th June.
After the mishap with Phase II, I was determined to make this shutter sturdy, with a couple of planks of tongue & groove from the demolished shed, various bits of 2 by 2 and various lumps of masonry serving the purpose. But for this phase (or perhaps lift would be the more correct term, even though lift is the term more usually applied to the successive pours to make a column, rather than a beam which is more usually made in one pour) I fell into the error of haste, thinking that I could get the job done before lunch. As a result the concrete mixing was a bit erratic, with the first few batches being rather dry - and I did not work hard enough at the tamping to clear all the voids at the bottom of the shutter. More concrete finishing needed in due course. Furthermore, the concrete being a bit stiff, did not settle flat and while the two ends are right, the middle is slightly high, maybe half an inch. It shows now, but perhaps when the concrete weathers down a bit and the garage wall is repainted it will not show so much.
Illustration in due course when the concrete finishing has taken its course.
In the meantime, I am pleased to report, that as things have turned out 0.6m of aggregate and five bags of cement was about right. There will be a bit left over, but not much and it will be easy enough to lose the bit of aggregate in the garden and the the bit of cement in the tip up the road. But I do not pass muster as a quantity surveyor, partly because I was changing the design as I went along, without any proper change control; the Young Turks from Pcubed (see http://www.pcubed.com/) with whom I used to work at the Home Office would not have been impressed at all.
PS: it would be interesting to know how things turned out there in the end: was their high end solution right for our mid range problem? Were the techniques used to manage the construction of oily facilities in the wilds of Kazakhstan the right thing for IT in Horseferry Road? What percentage of the budget did they manage to collar before they moved off onto their next punter?
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