Reinforced Concrete

... or how we were slurry when it didn't mesh

A contractor tries to cut corners at our expense

Reinforced concrete is a universal material which is reasonably well-understood in its structure, behaviour and performance. Placing it is normally just a matter of commonsense and a bit of experience so the need for a reinforced concrete slab for our outside swimming pool did not immediately instil fear into us. Perhaps it should have done.

In the days leading up to this pour, our contractor had become more and more frantic as his cash problem increased (see other pages for more information on this). Fortunately his workforce are accustomed to his panic attacks so carried on in their preparations.

The first problem with the reinforced concrete occurred when I asked the contractor if he had sorted out which premix plant he was going to order the concrete from and also what the specification of mix was to be used. He seemed adamant that the way to do it was to mix it all in his small, electric mixer; not really a viable consideration. He said he had been quoted €120 per cubic metre by a premix company for delivering it to our site yet when my wife phoned we were quoted €75 per cubic metre for exactly the same mix specification.

He was visibly furious at the unspoken suggestion that he had grossly inflated the price to us and he attacked the concrete company's representative on his mobile telephone to such an extent that I feared both he and us would be blacklisted.

The next difficulty occurred when it came to aligning the stanchions for the swimming pool. To this day I am not sure how he proposed to get these 6 steel columns to stand in line vertically, horizontally and to be to level, too. I asked his men to lay a 50mm thick 'blinding' concrete layer so that at least they would have a clean, hard and solid surface to fix these stanchions to and not just trying to wedge them into soil.

The second problem occurred when he arrived with a load of metal 'stirrups' so-called because they loosely resemble their namesake. They are used to separate the top and bottom layers of reinforcement - both of which need at least 50mm of cover to prevent the corrosion of the steel. Unfortunately he had forgotten to take into account the blinding concrete we were going to lay so the feet of the stirrups would need to actually sit on the soil below the blinding concrete where they would immediately begin to corrode.

The ultimate fiasco was yet to happen.

Because we were concerned over the contractor's solvency, we had agreed a fixed, lump sum price with him for the slab. As a result, though, we had to relinquish control over his modus operandi. This gave him the opportunity he wanted to insist on mixing the concrete using his own labour. When I pointed out that two operatives was not enough to mix and place 18 cubic metres of concrete in one day, he assured us that more would be available on the day.

Over the next few days a large pile of cement sacks and ballast arrived ready for the scheduled pour which was due to commence at 8 am on a Saturday and continue uninterrupted until it was completely finished.

The Saturday for the reinforced concrete pour came and there was only the regular two labourers plus himself available - wholly inadequate for the task at hand. I probably should not have let them begin mixing but, in any case, within an hour of the pour beginning we had to stop it. The concrete being poured was awash with water - more of a slurry than a conglomerate. There was no way that it would have passed a slump test. On top of that, my wife had noticed that the cement being used was all past its expiry date. Finally, the cement and ballast was scarcely being 'shown' the mixer before being tipped into a barrow. Instead of 5 to 7 minutes of mixing, each batch was getting around one minute.

I was about to condemn it when our contractor produced an electric poker vibrator. I had previously emphasised how important it was to see that all the air was vibrated out of the concrete to prevent 'rats nesting' as it is called. He assured me that this rather small poker was adequate for the purpose but, in any case, it was rusted solid and refused to work. That was the final straw for me and I gave the thumbs-down to the whole venture.

With considerable cursing, the slurry was scooped up into wheelbarrows and loaded on to the lorry belonging to the contractor. The steel was lifted, too, in order to get to the underlying concrete. It was then wiped clean and set aside to be reused. Eventually the lorry drove off, dripping cement-coloured water as it did, to tip the concrete in a yard the contractor was building.

Several hours later we were left with a rather damp layer of concrete blinding instead of a rapidly hardening slab of reinforced concrete. My wife and I were furious that our contractor had tried such a blatant and almost insulting con on us. He was being paid nearly €2,000 for the supply of the concrete (just the concrete, not the reinforcement or the labour) and he had tried to rip us off with a few hundred euros worth of out of date concrete, some ballast and an excess of our own tap water.

I suppose the only thing to his credit is that he never once subsequently suggest that we owed him for it - just as well!

Click here to find out how we used premix concrete to actually get our usable slab of reinforced concrete.