I had to make 3 trips to the local B&Q today to load up on all-in ballast. Â This I’m not too bothered with, but I did get looks from the same bloke who served me each time. Â Maybe he thought I liked the way he grunted his thanks at me each time I paid for more ballast, perhaps he became confused and thought he was having some sort of Groundhog day. Â I like to think that several people made many return trips to the store today, and fused the checkout boysÂ cerebralÂ cortex as he wondered if deja vu wasn’t actually a small village near Brittany.
Yesterday, we poured up to the top of the damp proof membrane, today we have to pour to the top of the formwork, and level off.
Once we’d poured plenty of concrete so that we were around 2 inches into the formwork, we positioned a sheet of steel reinforcement mesh. Â Again, if you’re doing this, make sure that the ends of the mesh have a decent amount of clearance to the edge of the slab, so as to reduce the chance of moisture attacking the steel.
Taking care to tamp the fresh concrete over the steel mesh, several mixer loads later, and we’d pretty much reached the top of the formwork. Â Psychologically, this was a good moment – it meant we could switch the mixer off, not have to open any more ballast and cement, and get on with levelling out.
Again, my IT desk job has done nothing to prepare me for estimating this task. Â 5 minutes? Â nearer and hour – we found that sliding the board back and forth was sometimes leaving small holes in the surface, which meant patching up, and then re-levelling bits that had already done. Â 6 inches from the end, disappointment (I’m sure I’m not the first person either, to beÂ disappointedÂ by 6 inches). Â We had to mix up a small amount of concrete to ensure we had a decent fill.
Finally we finished – we both felt pretty good, it looked great, and we were knackered. Â It was also well into Sunday evening, and whilst I don’t tune into Songs of Praise, I did want to go in for the night, and my Mum probably wanted my Dad to go home as he’d spent 3 days helping me out. Â I had planned to use an arris edge trowel, and then a float over the top for a smooth professional finish. Â In the end, I bottled it, as I knew I’d just cock it up, and we’d have to mix more concrete, re-level, and then run away from one irate parent (whom I could not have done any of this without)
So, this slab, with 300mm footings on clay (slightly deeper in parts) and a 5 inch slab (mixing my measurement units, the surveyor in me hangs my head in shame), this bit of the project used a 5:1 concrete mix, which used 46 25kg bags of all in ballast, 11 bags of cement, 12mm rebar, reinforcement mesh, and a rocking lunch one day made by Mrs Barrelvaultoven – Sausage rolls, gala pie, scotch egg, crisps. Â I had a bloody good weekend, and if you’re considering a project like this, I think this will be the most intense part, but well worth going through