August/September 2009

A Basement Is Born

With the outer basement walls complete, and the shuttering removed, the block workers came in to build the internal walls.
The insulated cavity is 300mm wide – three times the width of the cavity in a conventional house. The uninsulated section,
nearest the camera, will be a storage area below the conservatory.

It was intriguing to see these walls being formed, as they will actually be the inside of our finished basement.
Along the top is a row of special load-bearing insulated blocks, which will prevent heat from the ground floor slab
above being conducted down into the basement walls.

On closer inspection it's easy to see the multitude of air bubbles which give these blocks
their insulating properties. Like a brick Aero bar, in a way.

Once the internal work had been completed, back-filling began around the basement,
which slowly began to disappear into the ground.

For environmental reasons we used crushed demolition waste instead of the usual freshly quarried aggregate.
This provides drainage, preventing pools of water forming outside the basement walls. The white polystyrene layer
protects the waterproofing material from the jagged edges of the rubble.

Now was the time to begin installing the 'ground tube' for the ventilation system. Fresh air is drawn into the house through
this tube, buried 3 metres underground where the temperature is relatively constant all year round. This means the air
is warmed in winter, and cooled in summer, helping to keep the internal temperature stable, but with no energy use at all.
On site to see their system being installed were Steve Richmond from Rehau UK, and visiting from Rehau USA, John Kimball.

Andrew and Sean from the groundworks team prepare the laser levelling device which helps them to install the
ground tube at the correct gradient..... aligning the beam with a sight placed at the far end of each length of pipe.

The trench is then carefully back-filled, one section at a time.

Honorary site manager Max, now fully health and safety compliant in his smart new high-visibility jacket,
checks the quality of the work.....

.....and issues instructions to an incredulous Sean.

Following the ground tube installation, back-filling continued, almost up to the final ground level.

Here's the basement, now very much in the ground, with construction underway on the structure which will support
the massive reinforced concrete ground floor slab, to be poured in-situ. More on this in the next update....