End of week 3

The lack of a posting for the last six days hasn't been because a lack of activity at ECF - far from it...! Building works on the house have continued on apace, whilst the hens and windfarm development have provided a welcome diversion from a busy site!

After the 200mm floor insulation was laid on Monday the damp proof membrane went down and the reinforcement mesh was cut and laid on top, supported on 40mm spacers to set them at the required depth within the slab. On Tuesday the heating contractors arrrived to tie the pipes to the mesh, but on investigating what seemed a minor query by the builder in respect of the structural drawings at the end of the day it was clear that we had a problem.

With about 70% of the heating pipes laid, it turned out that the reinforcement mesh to which they were tied had been laid incorrectly and needed to be rotated by 90 deg. in plan. The floor slab was designed to use a 'uni-directional' mesh which is stronger in tension in one direction than the other - and guess what....! To be fair to builder and architect, it simply wasn't obvious from the structural drawings and on Wednesday everyone simply got on with dealing with the problem and close of play saw the project at a similar stage as 24hrs earlier - albeit with the mesh now correctly orientated. It was a gloomy day however, as whilst there was little material wastage, all of the underfloorheating pipes had to be pulled off and re-tied along with all the mesh which had to be removed and re-cut.

By Friday everyone had moved on and at 0745 a large crew had gathered on site awaiting the first of three deliveries of concrete, which subsequelty arrived at 0800 - bang on schedule. With expansion strips fitted to the inside edge of the slab 'form' and a top layer of reinforcement placed over supporting wall points, the resident digger started to scoop the concrete onto the previous three weeks work. A 'bunyan striker' bar (a huge rotating roller) was used to level/vibrate/compact this sloppy mix into the mesh/pipes. By late morning th whole lot was poured and levelled and the crew got on with finishing off the rest of ground works. The afternoon was spent further levelling the concrete by hand and by 5pm the job was done.

In all 21 cu.m of concrete was used, 95% of which is supported on packing foam! This will add 'thermal mass' to the building and help to ensure a stable, comfortable internal temperature.

Day 11...

Since Debs' post this morning, by the time the crew left at the end of the working day the hardcore and type 1 material was in with sand blinding on top ready for the insulation to be installed. This point marks the first departure from conventionality, as the next stage is to install 200mm of polystyrene insulation ready for the 20 tonnes of concrete slab to be poured on top of it.
Usual practice is to pour the slab at this stage, then insulate it and pour 50-70mm of screed on top within which the underfloor heating pipes are installed. We're cutting out the screed and going for a single pour of 150mm, which will will also contain the underfloor heating pipes within this massive slab.

The theory behind this is that we will be using a lightweight (timber frame) structure to build the house, this being common practice in Scotland and fairly standard in Scandinavian countries and North America. Whilst there are many advantages of timber frame construction over heavyweight masonry, well insulated timber buildings can be liable to overheating in summer and internal temperature/comfort levels can be difficult to stabilise. Introducing 'thermal mass' elements into the structure compensate for this...which is where the heavyweight floor slab comes in. In addition we have specified high density wood fibre and mineral wool insulation for the walls and roof which will also add to the thermal mass of the building as a whole.

Drainage

Work today is concentrating on getting the drainage in place, notably for surface and rain water as the foul drainage is already in place from the edge of the previous house to the septic tank.

Its currently very sunny but also very chilly and we're expecting the first frost of the season tonight. As a family of 4 we are living in a large caravan on site - this is generally pretty comfortable but the cold mornings are not that pleasant....and its only September. The house is expected to be complete around March 08.

Day 3

With concrete founds set and sight lines re-established, work starts on the dwarf walls which will support the slab. We had good dry weather today and good progress was made.

At the same wok continues apace made on the retaining wall opposite the house. The soil behind this used to be retained by the wall of a cow shed which was demolished to allow more light to the house and improve its setting. The new wall is constructed fom 150mm dense concrete block and then faced in sandstone (laid dry) reclaimed form the original farmhouse.