Last month, I explained how my wife Linda and I had received planning approval for our house designs for the two adjacent plots of land in Berry Hill in the Forest of Dean, Gloucestershire — one house for us, and the second for Bruce Bendall, my builder friend from the area, and his wife Kathy, who we sold the second plot to. In return, Bruce agreed to sign a contract to build our new home, contiguously with his own.
With approval granted, we began clearing the site, carving out the driveway and creating the level plinths for the two houses ready for the foundations.
Starting the Foundations
Why does it always rain when one digs foundations? I have lost count of the number of foundations that I have been involved in, and I simply can’t remember a trench that wasn’t filled full of water.
The actual dig went fine and Simon Drake, our building inspector, came out to see the trenches and both he and the inspecting architect were satisfied. However, later that evening it started to rain and by the next morning there was water sitting in the bottom of the trenches and several of the sides had fallen in.
The day cheered up though, giving Bruce and his two sons time to clear the trenches out and get ready for the concrete lorries, which duly began to arrive by mid morning. Bruce had opted not to use a pump, so the lorries backed up the drive and deposited the concrete straight into both sets of the foundations. It had to be a pretty wet mix, and by heaving it around with rakes both foundations were concreted by the end of the day. My foundations took a total of 19m³ of concrete.
There’s almost an audible sigh of relief when the concrete is in for the foundations. It’s a major hurdle. Despite all of the planning and all of the investigation, one doesn’t completely know what you’re going to come across until it’s all dug out. Fortunately all proved fine on our plots. From now on we’d be building up and not down and that’s a great feeling.
Bricklayers Tom and Sam, who’d worked on our previous two homes, joined us the following day. Unfortunately, the block company let us down and Bruce had to spend much of his time running backwards and forwards to Jewson picking up packs of blocks, which they let us have at almost the same rate as the full load that turned up a day later.
Within two days, both sites were up to damp-proof course level, ready for oversite.
Building the Oversite
We’d opted for a concrete oversite rather than a beam and block floor — the reason being that we’d carved out level plinths into a substrate mixture of sand, clay and stone that compacted beautifully and, when damped, set almost like concrete itself. Bruce built up the levels before blinding with sand.
We then had another departure from the norm. Both Bruce and I have had problems in the past with self-levelling screeds and difficulty in getting floor tiles to stick to them. So we decided that we’d do away with the need for a screed and that the concrete oversite itself would be our finished floor.
It’s controversial, I admit. A good number of people reckon that the underfloor heating won’t be as responsive buried in the solid slab as it would be within a lightweight screed. Others, including myself and Bruce, think that underfloor heating relies on the slow release of heat from a thermal mass and that, while it may not be as responsive, that’s the whole point: it’s what makes it different to the on/off instantaneous heat of radiator systems.
The consolidated and blinded oversite was overlaid with a membrane and then 100mm solid slab flooring insulation laid. Reinforcement mesh was then placed and the underfloor heating loops were wired to it. We were ready for oversite and, this time, Bruce had opted to use a pump.
Came the day for concreting and everything was ready. Six men, plus me in a purely management capacity, were all geared up for it. We had a roller tamper hired in and ready, and a machine to float and polish the concrete to create a finished surface. We waited for the pump to arrive with constant calls going back and forth from the concrete suppliers.
That afternoon, the pump turned up and shortly after the driver had set it up and primed it, the first concrete lorries started to arrive. I always liken the pump to an elephant with a bad cold, but it certainly is an efficient way to get concrete to exactly where you want it. Additionally, the action of standing on the mesh ensured that it ended up centrally in the mix, together with the underfloor heating pipes.
My house took just 6m³ of concrete and Bruce’s took a little more as he opted to put in the foundations and oversite for a conservatory. In any event, it was late evening before both oversites were tamped level and, as one is supposed to leave up to seven hours before using the power float machine, it meant that this would have to wait until morning. In fact, Bruce got there at 5am the following day and tried to use the machine, but by then the concrete had gone off too much.
Although we had level oversites, they were not quite the polished glass-like finish that we’d been hoping for. Never mind, we will have to use a levelling compound before we lay the tiles and timber flooring that we’re both planning to use.
There’s nothing more depressing than a building site that’s empty in the daytime. But equally, at the end of a busy day, when everybody’s gone home, I find it a magical place. That evening I sat on a pile of blocks and looked out from the site. The birds were singing, the sun was shining and my oversite lay there waiting for the activity of the next day.
“I have waited all my life to live here,” I thought. “Everything we have done before has led up to this point.”
A concrete pump may seem a large and unnecessary expense, but I think it is really worthwhile. Ours cost £408 for the day. The driver pitched in and helped with directing the nozzle and the concrete lorries came in quick succession. It allowed us to place the concrete where we needed it and it effectively vibrated it to fill every void.
If it had come earlier in the day, as we’d planned, it would have given us the time to deal with and properly float finish the oversites.