We have piles!

Last week, we took our boat up to Crick for the annual show there.  Whilst we were away, we got a message from our site manager explaining that he had a surprise for us when we returned.  He appeared to be alluding to something positive which is quite unusual when house-building, so we were intrigued to say the least.  After a few more days cruising, we returned to find that the scaffolding had now been removed from the south side of the house.  This was expected, so this couldn't possibly be what the surprise was.  All became clear when we walked up to the site office and found that the builders had borrowed some of our topsoil and created a small garden in front of the site office.  In the centre, a small white board stands proud, waiting for the house name to be emblazoned upon it.  Well, I suppose we have to start somewhere!

Our 'surprise'

This week, the main focus of work has shifted outside.  It is a condition of planning that in order to protect the roots of nearby trees, the garage foundations for the garage must be based on piles rather than the more traditional (and cheaper) trenches.  A piling contractor was commissioned to install the required 5 piles.  This is done using a large auger which although is not a quiet operation, it is significantly more neighbour-friendly than hammering columns into the ground.  The auger drills a 300mm diameter hole which in our case has to be 10m deep, or until solid rock is encountered.  The hole is then filled with a steel cage and filled with grout.  A 'ring beam' is then fitted to the top of the piles and the garage is constructed on top of that.

 

Steel cages ready to be lowered into the holes

The drilling rig is not quite the size you might expect to see in the North Sea, but the operating principle is the same.  The bit is drilled into the hole, and then another section of drill bit is hoisted up and connected to it, before drilling further down.  In order to get to 10m, up to 10 one-metre sections are needed.  A mini-excavator is needed to move the spoil away from the hole.

The Drilling Rig is hidden behind the excavator.

The following video shows one of the drill bit sections doing its stuff.  Initially progress was good, but as the ground got tougher, progress slowed considerably.

At the end of day one, 3 of the 5 piles have been created.  Tomorrow, the remaining two will be put in place.  We then need to wait 4 or 5 days for them to cure, at which point the piling contractor will return and test the strength of each pile.  Hopefully, then construction of the garage can commence.