BUILDING STARTS!

Following a weekend site visit by our foundation engineer, we were advised of the steel reinforcing, and concrete strength and dimensions required for the strip foundations. The steel was ordered on Monday and delivered on site Tuesday 6 December 2011. Our builder, Pieter Olyn, made quick work of cutting and tying the steel rebar, and placing it in the foundation trenches.

Steel reinforcing, consisting of 4 rows of 12mm rebar tied at 750mm intervals with 10mm rebar

The first of 3 batches of readymix concrete was delivered on site Wednesday 7 December 2011. This was a 6cu.m batch of 15Mpa concrete for the boundary wall foundations. We are using a local company called Ciolli Brothers. They have a stone quarry and concrete plant just a few kilometers from the site. The cement specified in the mix is 40% slag [ground granulated blastfurnace slag or GGBS - an effective cement substitute], a waste material collected from iron smelters. This is sometimes mixed with cement in varying proportions and sold as Eco-Cement by some companies. As it is a by-product or waste material, it has a significantly reduced carbon footprint compared to regular virgin cement. This fact, together with the close proximity of the quarry and concrete plant to the site, makes the concrete as environmentally sound as is reasonably possible on a tight budget. Our concrete supplier does not even market his concrete as an environmental choice, and it did undercut the quoted price from large multinational suppliers. My advice, do research on your suppliers and educate yourself about the options, as environmentally responsible materials are not always the more expensive option.

Pouring a section for the front boundary wall foundation

OOPS! Partial collapse of the house foundation trench, cause by the heavy truck

 The concrete pour started with 2 cu.m for the front boundary walls, easily accessed from the road. Getting the concrete to the rear boundary wall trench was a little bit more tricky though. The driver had to manoeuvre the truck down the narrower south side of the site, as the sand on the wider north side was too loose to drive on. After a few tries over this still loose sand, he managed to get through, despite a heart stopping moment of soil collapse into the house foundation trench. The remaining 4 cu.m were poured at the rear boundary, and he went on his way within the allotted 45 minutes.

Pouring concrete in the rear boundary wall foundation trench