Author: Shaun

Date:21/02/2016 18:33

We started building the back wall of the swimming lane today! We managed to
do 43 blocks with 3 mixer loads of mortar before it got dark. Each row of
the wall contains 50 blocks and we are doing 5 rows at this stage.

It was quite difficult in keeping consistent with the mortar gap between the
concrete blocks and not let it “run” ahead! We had to keep it down to 10mm
or less because we got our steel rods going up through the hollow cores,
meaning keeping the rods fairly clear of the edges of the blocks.

And the other discovery we learnt, is the sloppiness of the mortar mix. Each
concrete block are much heavier than house bricks so they press down with
27kg of force, on their narrow edges, which means they squeezed out the
mortar if it is too sloppy.

We make a strong mortar mix using 1 bucket of sharp sand with 2 buckets of
soft sand (a “Builder’s” bucket is about 13litres) which gives a total of
40litres of sand, together with a 10litre bucket of cement (a complete 25kg
bag fills just about 2 10litre buckets).

Currently, we are working with 4litres of water (plus 100ml of plasticiser)
and this produces a slightly sticky and sloppy mix which just about holds up
the block.

It takes a little while for our electric mixer to produce the “flop”
consistency, and it seems that the plasticiser then starts creating
microscopic air bubbles which makes the mix even more sloppy after another
couple of minutes. We think we will reduce the plasticiser down to 50ml in
our next mix.

We will inspect our build in the morning to judge the quality of our current
mortar mix!!

Only 207 blocks to go!!

First-42-Blocks-placed

We moved all the 120 concrete blocks over to the slab, spread out along the
whole length (22.5metres), ready to build up 2 layers of the back wall, and
the extras at the beginning, ready for the end section of the swimming lane,
and the first few blocks on the front wall.

We used our new purposed built trolley to move 10 blocks at a time, weighing
in at least 250kg in total, pushing and pulling the load over the slightly
soggy ground (we had a recent rain fall!) and rather bumpy at times too.
Hard Work!

First-two-rows-opf-blocks-ready-for-building

We also removed the shuttering framework that was wrapping around the
foundation slab. The 89mm CLS timber, all 10 lengths of them, are now piled
up on the side, ready for the next shuttering job of the main house’s
foundations.

Three pallets of concrete (215mm x 215mm x 440mm ) blocks, a pallet of Blue
Circle cement bags and a ton of soft sand arrives today.

It is our first delivery of many, many pallets of concrete blocks to come!

It was amazing to see how far the Jewson’s delivery lorry managed to lift
each pallet over from our Loke, over the top of the stack of OSB sheets and
put them down actually in our “hole”! Wow!

After two days of rest to recover from the hectic episode of getting the
ready-mixed concrete in, we today, went out to cut slots in the slab to
“guide” cracks caused by the contraction of the drying and curing concrete.

The basic formula is 30mm for every 1mm thickness of the slab, which in our
case, the slab being 100mm thick, means that a series of slots is needed
every 3metres, so we cut 8 slots in total. We used a diamond coated cutting
disc (250mm diameter) in an angle grinder machine and cut 25mm deep slots.

Then we dismantled the framework that was holding the reinforcing rods in
place and put bright “lime” green domes on the ends of the sticking up steel
rods to protect us from potential accidents of falling over and piercing our
bodies right through, nasty or what!!

We now have an “avenue” of green “flowers” on steel stalks!!

Our ready mixed concrete duly arrived this morning, 8am sharp! We managed to
get our little extension chute installed on the dumper truck in time and
park it over by the Loke.

But when the concrete lorry arrived, he had only one extension chute himself
and wouldn’t or couldn’t reach our dumper truck. So we had to drive the
truck up onto the upper level, and only just managed to get their chute to
go into our skip!!

Anyway, it went reasonably smoothly after that, went back and forth a half
dozen times, distributing the concrete all the way along our trench. That
phase took 45minutes to empty his lorry load of concrete!

It then took us a further 7 hours to push and shove the piles of wet gravel
concrete into all the corners and in and around the re-bars, then chump it
down, level it off, and get a fairly flat finish. We couldn’t use the float
at the end as the mix had already set too hard by then.

Concrete poured and compacted

We stumbled and staggered back in doors after cleaning the dumper and
wheelbarrow plus tools with the garden hose, washed our gloves and overalls
of the worse of the cement. We had put on latex gloves underneath our tough
rubber coated gloves to protect our hands from the alkaline burns. Thanks
goodness!!

So at last, the swimming lane, currently 22.75metres long, now has a
foundation formed and it is now curing and hardening. All the reinforcing
rods are sticking out of the concrete, ready for the hollow concrete blocks
and we can then rebuild the ground up behind the soon to be new wall and
rebuild the fence again!!

The last 3 or 4 days has been very, very hectic getting everything ready!!
Phew! We will have a day or two off now to recover!!

The framework for holding the reinforcing bars in the correct positions, has
been constructed using our pile of 63mm CLS timber. We drove in pegs and
posts to hold the framework together and get the straight lines. this was done yesterday and Friday.

We then spent today (Sunday) mounting the re-bars themselves onto the “rails”,
positioned at every 225mm, which is the repeat distance between the holes in
the hollow concrete blocks.

And we used broken pieces of 50mm concrete paving slabs to stabilised the
steel rods in the bottom of the trench.

we didn’t finish this job until 10pm tonight!! we had to get this done before tomorrow and the arrival of the ready mixed concrete!! Phew!

Rebar Framing Ready

Rebar in Place

We have ordered 4 cubic metres of ready mixed concrete for Monday 8am! The
price has gone up since 5 years ago and now is £425 for this load!! Yes, it
is not a full load of 6 cubic metres and therefore we must pay an ?empty?
charge to cover the cost of the driver and equipment but still, the price is
a shock!

Today, we started on the job of slicing up 55 6metres steel bars into 105
lengths of 2metres, and 100 lengths of 1metre.

Then all were bent right angles, so that it would be buried in the concrete
slab and provide vertical reinforcing rods for the hollow blocks.

Pile of cut and Bent Re-Bar

Tomorrow, we will create the wooden framework to hold these rods in their
correct position.