October 2009

Moving On Up

Following the construction of the basement walls, building work continued on the elaborate structure
that would support the massive concrete ground-floor slab until it hardened.

Getting everything level is important.

With the scaffolding and shuttering in place, work started on the labyrinthine framework
of steel reinforcements which will give the floor its strength.

An almost unbelievable 17,000 joints had to be made to tie it all together, so work went on for several days.

A floor this massive wouldn't be out of place in a multi-storey car park, but this structure, weighing around 50 tons,
will be a critical component in the thermal mass of the building – storing heat in the daytime and giving it back at night.
All this mass will also help to keep the house cool during hot weather.

Andrew LeBrun provides the on-site entertainment by getting his boot stuck in the steelwork....

......while site manager Max helps Tim check that the joints are in order.
The earthenware pots set into the steel will create holes in the poured concrete for cables and pipework. The two larger ones,
nearest the camera, are for the toilet chutes to pass through into the composting chamber in the basement.

Project manager Mike Neate and his business partner Graham (left) check all the dimensions are correct.

And finally the pouring can begin.

Most of the concreting so far has coincided with heavy rain.....

.....so it was good to have fine weather this time, meaning the entire operation went very smoothly.

With six full days needed until the ground floor slab was fully hardened, our groundworks team moved on to the
soakaway, which will receive grey water from the house, and also rainwater, should the tanks in the basement
ever fill to overflowing. The soakaway is formed from three huge concrete rings.......

......one of which was already in the ground, being prepared for the next two to be lowered in.

Slowly and carefully does it.....

Finally, a concrete lid is lowered on. A small inspection cover is all that will be visible in the garden once this is completed.

The drain-runs to the soakaway are being laid in traditional clayware pipes. We're trying to use as little PVC as possible
in the construction of the house, as significant amounts of toxic chemicals are produced during its manufacture.
Unfortunately, practical and cost considerations have meant we can't eliminate it entirely.

Benched concrete inspection chambers are something of a rarity now that PVC is so widely used under ground.

Here Tim's getting on with the blockwork for the front porch foundations. No door into the main part of the house
opens directly to the outside – there's always an 'air lock', to help keep the interior temperature stable.

Because it will carry part of the weight of the main roof, the porch foundations are the same depth as the main house,
so there are more than 3 metres of concrete below these foundation blocks.

With ground work progressing rapidly, our rainwater tanks arrived. These 1500 Litre 'Rotoplas' tanks are used to import
concentrated fruit juices, but after just one journey they're effectively scrap, so we're going to use them in our rainwater
harvesting system. They came direct from Britvic Soft Drinks, still containing some rather nasty stale orangey gunge.
Much to everyone's amusement, Mike got a good soaking every time he lifted one off the lorry.

Strange that no one else volunteered to carry the top end.

Eight unloaded – four more to go. Over 16 tons of water storage – but then we're not connecting to the mains water supply.

Before we can carry the tanks down into the basement, we'll need some kind of staircase,
so why not build one out of old scaffolding planks?

With the ground floor slab finally hardened, the block layers arrived to start building the internal leaf of the ground floor walls.

Like the floor slabs, these 140mm dense concrete block walls form part of the thermal mass of the building.

'There's mortar this than meets the eye'. Brickies' assistant Alice contemplates the business of block building.

Cutting these high density blocks is dusty work.

Because we need the house to be as airtight as possible – think extreme draught-proofing – the blocks
need to be laid accurately, so that there are no gaps in the mortar......

..although the final airtight 'seal' will be provided when the walls are plastered on the inside.
On the outside there will eventually be 375mm of insulation, plus the outer skin.

As the walls continued to go up, Mike put the finishing touches to the temporary basement staircase.
A smarter wooden stair will eventually replace it, but we don't want it to be damaged during the building work,
so this one will remain in place until all work down below has been completed.

With the temporary stairs carefully lowered into position.....

.....we were able to visit our brand new basement – looking very wet at the moment. We're going to have
to get down here and pump out this water as soon as possible.

So we're now well on the way to seeing how the ground floor will actually look. Soon the scaffolding will arrive,
so that the blockwork can be continued up to first floor level. At that point, preparations
will begin to construct the second and final massive reinforced concrete floor slab.

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