Self Build BlogFoundation reinforcing steel cage ready for pouring concrete
Apparently it's strong enough to build a block of flats onto!
It's only taken a few days - once the foundation trench excavation was done - to build the reinforcing steel cage, which will strengthen the house foundations and retaining wall structure.
This part of the build is more of an engineering project than a house build, as so much time, effort and materials are going into making the combined retaining wall & house foundations strong enough.
When the concrete is set, this solid mass will support both the house and the retaining wall at the back of the plot. It has to be strong enough to prevent any movement (rotation) caused by the pressure from the earth being held up - this also includes road and all the traffic which runs along it (although it's only a suburban through-road, rather than a main road as such). Plus the back of the house itself shares this foundation, so it's a much more complex construction that a normal house build.
The reinforcing steel cage is made up of steel mesh (pre-welded steel bars to form a grid) and lots of individual steel bars (straight and pre-formed corners). Everything is hammered into the ground and tied together with wire.
In the photos you can see various single vertical steel rods placed all around the dug trenches. On the top of each there is a painted yellow marker. These have been hammered into the ground at exact heights, so that when the concrete is poured they know exactly what levels it needs to come up to. Simple but clever.
We should have been at this stage a couple of months ago - and on a normal build (without digging into a hillside) we would have been at this stage after about a month I reckon. But obviously there have been numerous issues and delays... and some things have had to of been done in a different order (like building the external boundary first). It's a relief to be finally come up out of the ground for a change.
