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Today, we sealed the end of the gap between the swimming lane’s back wall
and the fence, by pouring in concrete into a mould. This End Cap was
necessary because the return channel needed to be built on a concrete
foundation which in turn sits on the hardcore / soil but near the garage end
of the swimming lane, there is going to be a filtration unit to “clean” up
the rain water and the soil would have leaked out from under the foundation
over time, so we capped it off.

End-Cap-1

End-Cap-3

End-Cap-2

End-Cap-Finished

It took 3 bags of cement to produce 200 litres of concrete to make a 150mm
thick wall from the bottom of the mass wall and swimming lane wall and the
gravel board of the fence, some 1450mm high and 600mm wide, with a slight L
shaped extension to the mass wall (this runs along and under the fence and
right across the back of the garage).

It will make a neat vertical wall, flush with the end of the swimming lane
and allow us to control what we want to install in that location without
worrying about the motions of rain soaked mud!!

The back wall is now completed with the 6th row of blocks laid today. we had
to do another 31 blocks to finish it off and 1 around the corner on the end
wall.

We continued along the front of the swimming lane to start the 1st row and
we did 12 blocks. It took longer to do those as we were being careful and
getting them level and at the right height so that the subsequence rows on
top come out neat and tidy.

Back-Wall-Complete

Start-of-Front-Wall

The back wall is done for now until the soil behind the wall has settled
down and compacted with future rain falls. It is likely to be several years
before we get back to doing the next task, the return channel feature of
the swimming lane.

The back wall is now doing the job of holding back the soil and water from
the higher grounds of our neighbours and we can hopefully forget about that
issue for now.

Today, after a couple of weeks delay while we waited for the concrete in the
back “retaining” wall, to cure and gain proficient strength, we released the
shored up soil of the land stretching across to our neighbours (the workshop
and a row of houses).

We inserted a sheet of DPM plastic to minimise the chances of wet dirty soil
from getting through our back wall and creating problems in the future,
hidden behind the fibre glass resin coating.

All the diagonal struts were proven to done a good job, because as we
removed them, the boards and posts leaned over under the weight of the soil
behind them. But we had mostly filled the gap between the concrete wall and
the OSB boards so the whole thing wouldn’t suddenly collapse and potentially
disturb the neighbour’s fence posts and panels!!

But we had problems removing the OSB sheets as they were too firmly held in.
We tried pulling them out using the mini-digger and rope, but the rope
sliced it way through the OSB! Wow! So we decided to leave them there as
mementoes and for ‘Timeteam’ to discover in some future archaeological dig!

Dpm-in-Place-and-Mostly-Filled-e1461138200943

Now we can finish off the 6th row and put on an end cap at the mass wall to
retain the soil from spilling out near the garage.

WOW! We finished it all today, even though we started much later at 11:30am
(due to having had an appointment in the morning). We did 38 columns using
9½ bags of cement!

We changed our jobs around so I could do the making and mixing the concrete
and Stephen took the wheelbarrows loaded with the concrete over and up to
the wall to pour in and vibrated each column down firmly. It was much more
efficient!! But Oh Boy .. We Are Knackered!!

Today, another 33 columns were filled!!

We decided that it would make sense to split the mixing load in half and do
only a half a bag of cement and 3 buckets of ballast. It works so much
better this way that we hardly need to fiddle with the cement mixer, just
put in 6 litres of water, half a bag of cement, mix this up for a second or
so, and then chuck in the 3 buckets of ballast .. and that’s it!! it is
virtually mixed all together as soon as the last bucket goes in. We do add a
quick spray of water to loosen the mixture up a bit and it then pours out of
the barrows and straight into the hollow columns.

So today, the columns were 6 blocks high, hence why we did only (huh!) 33
for the 9 bags, whereas yesterday we did 31 columns for 8 bags. But
yesterday, we were doing just 5 blocks high columns!! That makes it a rate
of three and two thirds columns per bag today, against three and seven
eighths columns per bag yesterday, if you are interested in the maths!

Saturday-33-Columns-Filled-1

Saturday-33-Columns-Filled-2

Today, we managed to fill a further 31 hollow columns in our retaining back
wall. This is 8 bags of cement, mixing each bag with 6 builders bucket of
ballast.

We found that putting in slightly more water in the mix, helps with the
pouring the concrete down into the hole and the vibrator thingy is very good
at knocking down the mixture. Very glad to have bought one off the web!

Friday-28-x-5-Block-Columns-Filled-2

Friday-28-x-5-Block-Columns-Filled-1

Friday-4-x-6-Block-Columns-Filled

We found that putting the water in first and 1 bucket of ballast, mixed up
before then adding the bag of cement. This creates a very wet and slurry
mixture to help distribute throughout the further 5 buckets we then put in
all at once and while the machine is stopped. Cannot add them while it is
going because the slurry will get pushed out of the drum!! We are using
about 12litres of water to bring up the resultant concrete to a good
“flowing” consistency.

So in summary, the concrete we are making is:
1 bag of cement
12 litres of water
6 large builders bucket (3 gallon / 13.5 litre capacity) of a mixture of
small stones crushed up to pea sized (10mm) and sharp sand.