After getting the all clear from building control, it’s time to fill the foundations of Ian Rock’s 100m2 extension project.
“It’s like pouring money into the ground,” said Godfrey the builder as we stood watching gallons of ready mix concrete swirl around the foundation trenches. It was a particularly poignant observation because the money at stake was mine, as I’d opted to fund all the materials directly.
This was the fifth and final truckload, totalling an impressive 28m3 — sufficient for a sizeable self build house. Luckily, Godfrey managed to call in a few favours with the concrete supplier and negotiate a significantly lower price per m3 (£79 + VAT) than I’d been quoted.
Ready for Inspection
I was mightily relieved to have reached the concreting stage without any major setbacks. Things hadn’t looked so rosy the day before as our freshly dug trenches began to rapidly fill with water a couple of hours before building control were due to carry out their first inspection.
There was just enough time to race over to the nearest tool-hire store and grab an industrial-sized pump, sufficient to suck a 2ft depth of water out of harm’s way. As Andrew, the local authority building control officer, arrived on site, the trench bottoms appeared pleasingly smooth, level and innocent of all but the faintest sheen of moisture, flanked by sufficiently firm sides ruling out the need for temporary shoring.
After 15 minutes of questions, Andrew seemed generally satisfied (save for commenting on the lack of hi-vis jackets on site), casually announcing: “You’re OK to carry on.” This was music to our ears.
Before drawing a line under a successful inspection, it’s advisable to check when building control want to visit next — in this case, at the beam and block floor stage the following week. I made a note to call them in good time.
Pouring the Concrete
Ordering concrete before you’ve got the all-clear from building control is risky — quantities may need to be changed or foundation designs radically modified at the last minute. But it’s even more risky leaving freshly excavated trenches exposed for too long without support from timber shoring.
This was particularly the case on our site as clay is prone to rapid drying, shrinking and cracking with a consequent risk of collapse. (Serious injuries from trench implosion, even fatalities, still unfortunately occur on poorly managed sites.)
This is where a little local influence can come in handy, and as a long-established building contractor Godfrey managed to pull a few strings to get a convoy of concrete wagons mobilised the following afternoon, rather than the more usual three to five days’ notice.
I needed to start placing orders for building materials, allowing a couple of days’ notice for deliveries of Portland cement, soft building sand (seven tonnes) plus packs of engineering bricks and blocks for the lower walls, not forgetting to chase up the ground floor beams on order.