Week 51-52 - Pouring New Concrete Slab

We are pouring a new concrete slab over the entire split bottom floor of the building. These areas do already have a concrete floor but it is no more than I thin skin over the hard-core foundations at points, extremely uneven, cracked and in multiple sections. All in all no good and more importantly we need the floor to be water proof for our new flood defense plans, so we are pouring a new waterproof concrete slab at a minimum of 10 cm thick over the whole floor. Unfortunately the old floor is so un-level, to get our 10cm thickness in the highest corner we are actually pouring 28cm in the lowest. All in all we have poured 24m3 which is well over 50 tonnes of new concrete. Now this stuff doesn’t grow on trees (I assume mainly for gravitational reasons) and this has been quite depressingly expensive… ‘yay new concrete floor!’ doesn’t quite have the same ring as ‘yay new motorbike!’ does it.

Having said that…… look how smooooth it is…

We poured the two different levels of the floor on two separate days, the first being the lower river side. It was just Graeme and I there to do the leveling, solely and completely due to this comment made by the concrete sales rep:

“This is self-leveling, free-flow concrete, we’ll pour it in through the window gap at the far end and it will pretty much spread itself out on its own: you’ll barely have to do anything.”

This was the biggest lie I have heard since this blond toff drove round in a bus telling us that leaving the EU would save £3 million a week. While it may have been ’more’ free flowing than your average concrete, it is in no way self-leveling over that distance. It quickly turned into one hardest days’ work of my life.

Concrete being pouring through window reveal

Trying to spread out and level the never ending supply of concrete pouring through the window. Five of the big spinning/wurly lorries we had in total. (and yes my inner 5 year old still thought they were super cool!)

Power floating the drying concrete...

The second pour on the higher ground floor area required a far bit more prep than the lower, as we had to build some fairly robust shuttering to hold the concrete where we wanted it while it set. This also involved creating a small ramp across the front doors of the building to the new floor height and a much larger ramp between the two floors.

The two old steps between the two levels before we started...

Steps taken out and floor above taken backwards to allow for a shallow ramp

Starting the ramp shuttering. Also you can see the re-bar been added to the stone wall to strengthen the new concrete retaining wall.

Finished shuttering from lower and upper level

Shuttering was then loaded with lots of ballast to help it stand up to the weight of the concrete 

I wasn’t going to be fooled by the reps marketing talk this time – I needed more man power for this pour. So once again I found myself, NOT stuck up a fell with a broken ankle – but I called Keswick mountain rescue anyway!

A huge thank you to Richard, Grahame and Big Chris for their help, especially as (and im being honest here – I could easily of left this part of the saga out!) my shuttering sprung a leak! I’ll use the saying ‘all’s well that ends well’, as this did end well. But I could have easily turned into a major disaster with all the wet concrete above pouring down over the new set concrete of the lower slab. We managed to find where it was getting through (at the bottom of the ramp shuttering) block it up and get all the escaped cement back up to the higher slab before it started to go off, or worse still give way completely.

The aftermath of the leak around the ramp

Finished ramp and retaining wall between the two levels

 Graeme trying to 'kick' the wet concrete out across the space! I mocked, but actually turned out to be a effective method.