Pouring the Floors

The monster concrete pump pouring the floor slabs for the two adjacent cottages, this covers the underfloor heating which is attached to the steel mesh. With the heating encased in the concrete slab this provides a high level of thermal mass to stabilise the internal temperature of the properties. We used the same principle on the main house which we built 3 1/2 years ago and it really works well, alongwith the high levels of insulation and air-tightness.

For the most part since commencing the build the weather in this part of the world has been unseasonly poor with twice the usual rainfall and generally lower temperatures. As the concrete was poured on a warm, sunny, breezy day the builders then had to spray water onto the surface to reduce the temperature as it set in order to avoid cracking.

Storms, the garden, the heat pump - bit of a catch up

Sunday morning was gloriously sunny so a couple of hours in the garden was fun. With work during the week and a wet n windy day on Saturday I've barely looked at the garden.
Behold - the ravaged spring greens aka caterpillar central. I've tried picking off the caterpillars and feeding them to the hens but in all honesty I don't think the hens like them; the hens easily demolish slugs and worms but perhaps these hairy black and yellow (cabbage whites) caterpillars aren't awfully tasty.


The ravages of Autumn....we've had some proper wild seasonal weather now; this is Loch Lomond on Saturday, looking more like the sea than an inland water. The changing stormy skyline looks impressive and its great having a refreshing walk by the Loch; but also nice to get home to a roaring woodburning stove and the cosiness of the house. Last night the heat pump switched itself to winter mode which essentially means its been consistently cooler outside now (ie the average outdoor temp including nighttime is below 10degC) so if the internal temp drops then the heating will come on in the house. For us we've set the internal temp to 20deg, although its usually 2 or 3 deg cooler upstairs where we have no heating.

Not sure if I'm pushing my luck by trying to sow a few seeds this late but 2 weeks ago I carved out three mini-plots with some old Aberfoyle slate and distributed spinach, sorrel and mispoona. The latter is a combination of mizuna and tatsoi; essentially an oriental style green which should work well as a salad or cooking vegetable. I tasted a few leaves today, it has a full buzzy vibrant taste like peppery rocket. So long as we get a bit more sunshine I think we'll get some pickings through October. Nothing ventured....

Other parts of the veggie garden are still in great vigour; we've just finished the courgettes and cauliflower but have recently started harvesting savoy cabbage. Brussel sprouts are forming nicely, the leeks are growing and of course the ever exuberant chard. Plenty of iron rich greens!

There's still plenty of colour in the robust calendula which seem to have survived the early Autumn storms. I do like this flower, its so simple, so happy. When I remember I pick a few heads and pluck then dry the petals; they make a good addition to a bath for relieving excema and dry skin. Even better when placed in a muslin type bag with organic porridge under a running tap - it really works.

Proof of the pudding...

It's December, and time I blogged again. The last seven months of occupancy have been intense at ECF, not only with moving in but also just catching up with 'normal' family and work life. Despite the festive season being just round the corner, we at least feel we're getting there!

On the energy front, seven months of occupancy means we've got some data on energy consumption to compare with what we specified and predicted...and the results are quite a relief!

The bottom line is that we're using 25% less energy than we expected; and that's in a house already designed to use less than a quarter of the energy of the average new housing stock. In general hot water and space heating energy use are on target, although these account for less than half of our predicted energy use. The big savings have thus been made in other energy use, namely lighting and appliances. In particular the use of LED and CFL light fittings, coupled with A and A+ energy rated kitchen appliances has paid dividends.

Whilst in most houses heating and hot water use accounts for up 80% of domestic energy demand, our experience just shows that real savings can be made with little effort by replacing lighting and appliances (when worn out of course!) with more energy efficient equivalents.

The Contura wood burning stove in place in the main sitting room. We sourced this through EcoLiving who also supplied the ground source heat pump. The photo below is of the less attractive connection through the main bedroom to the chimney but this will be boxed in when the fitting is complete. This will still be a few days as the lower section of the external chimney and roof flashing need to be replaced because they have been damaged on site and a good seal with the internal pipes can't be achieved.

The slate tiles in the hallway will receive another coat of seal this weekend.

Just a short while left in our temporary home - we moved in here in mid June 07 and we're moving out next week. Its been pretty hard work at times and I can still feel the cold of the week before Christmas but being on site while the house has been built has been fun and essential.

Hello again after another week has passed in a flurry of activity. The weather has changed significantly for the better and it has been dry for nearly a week which is quite remarkable after at least a month of driving storms. We spent a lot of time outside at the weekend, I was planting bulbs and Steve was building the climbing frame. With the advent of fine weather after such a long spell of hibernation it seemed that many of our local friends were out for walks and cycle rides so popped by for a viewing and it was a real pleasure to have so much progress to show people.
The big event of last Thursday was the switch on of the heating system and by Friday the builders were over warm and had all the windows open. We were mightily relieved and feel quite chuffed that it is already performing so well - partly because some observers are unsure of our reliance on renewable energy so its good to have an early positive response and mainly because we're desperately looking forward to living in the house. The system is being commissioned tomorrow. It will be interesting over the course of the first full year in the house to see how the comfort levels change and what running costs we encounter.
We need to have paint colours decided and bathroom tiles purchased by the end of this week for the upper floor so feel slightly under pressure. The bath and washbasin are fixed in the family bathroom and most of the other goods are in our en-suite if not actually plumbed in. I'm collecting an alternative shower tray tomorrow whilst on the way to order the kitchen and utility room cabinets.
Externally the brickwork is complete and I think the rendering commences next week. There appears to have been a change from the early days when Steve and I thought we were getting a smooth white render and the current drawings specify wet dash. I think this is being resolved but to be honest I can't remember where we're at with this..........just about sums things up as we juggle house building needs with the business and family. Plenty of evenings of work for us and lots of scraps of paper and lists here and there.

Heat pump installation

Work started on installing our heat pump last week. We have specified a Nibe 1240-5kW - the smallest capacity they make - with integral 'tank-in-tank' hot water cylinder. It 's a very neat unit, being the same size as a 1.9m tall fridge freezer. The pipework next to it will be ultimately enclosed in a cupboard which will still have some storage space at the front, whilst allowing access to the pipes at the back if need be.

Specifying a heat pump uses the opposite logic to specifiying a combustion boiler, as it must be just undersized to operate at its most efficient when taking into account the building's heat loss and anticipated peak heat requirement. The reason for this is that heat pumps dislike being 'cycled' - switched on and off - and actually benefit from running for longer periods at a time than conventional boilers. In extreme circumstances where, say, there is significant heat and hot water demand (eg. Christmas with visitors!) then the heat pump employs an electrical element to supplement itself, but the trick is to set things up so this hardly needs to be used at all, electricity being a relatively high-carbon form of energy.

The unit is being installed in our utility room where all the pipes from the ground loop, hot and cold water, underfloor heating and 1st floor radiators/towel radiators terminate. The guys are making a neat job of connecting this spaghetti together and hopefully by late next week we should be in good shape to switch on and get some heat into the 40 tonnes or so of concrete which forms the floor slab.

As it happens one of the founders of the heat pump supply company - Ecoliving - popped round yesterday to look at our windows (he's building an extension to his own house!) and he told me that the heat pump even had a setting to dry the floor slab out over a four day cycle, this will be important before we fit engineered board flooring.

Anderson Floor Warming of Glasgow are doing all of the plumbing in the house using a German plastic/aluminium pipe system. Hot and cold feeds are fed to manifolds from which each tap is fed, thus reducing pipe runs. Also the hot water feed is circulated from and back to the hot water tank at peak use periods (controlled by a timer) such that when a hot tap is switched on, hot water appears almost instantly.

Apart from the plumbers, the rest of the guys on site have never built a house with a heat pump in it and we are all waiting in anticipation for switch on!

Lots of trades on site.

The underfloor heating folk have been here today. We are not having any heating upstairs except for underfloor heating in the 2 bathrooms. This will be served by the ground source heat pump as per the ground floor, albeit in trays rather than embedded in the concrete as they are on the ground floor. As the first floor is laid the guys have to work from the underside of that floor, I can't imagine that's easy but they seem to be managing just fine.

The 6 joiners who are here are covering various tasks - the exciting one for us is seeing the main first floor picture window being framed out. A number of adjustments have been made to this but it is now looking good. Inside the first stages of first floor interior walls are being established; the children have already decided which 'bedroom' is theirs by virtue of which windows they have adopted.

There are lots of issues we are trying to resolve - the wrong cladding being one. More on that later...

Weather report - its positively balmy here today. I think we are becoming so hardy and acclimitised that we don't realise its December.

Heat Pump: Part 1 - ground loop

As previously mentioned we have opted to use a ground source heat pump to provide both space and hot water heating. With no mains gas, an adjacent field and the opportunity to design a well insulated house from scratch with underfloor heating, the heat pump was the lowest carbon and lowest running cost option for East Cambusmoon.

For anyone considering a heat pump for their own house there aren't that many situations where it is the most cost effective and efficient choice, and certainly if you have the luxury of a mains gas supply a high efficiency gas boiler, coupled with say solar thermal panels will likely be a lower capital cost and running cost option than a heat pump doing both. If not on mains gas, then the costs need to be compared to LPG or oil and the decision will largely depend on the type of heating distribution system you already have, ie. radiators or underfloor heating. For the same heat input to a room, radiators need to be run at a higher temperature than underfloor heating simply because the heat emitter is concentrated into a relatively small wall hung panel, rather than the entire surface area of the floor. The problem with heat pumps is that their efficiency rapidly decreases in proportion to the heating medium temperature, such that running small radiaors from a heat pump is a bad idea. This can be alleviated to a certain extend by increasing the size of radiators so they can be run at a lower temperature.

Then there's the heat collection system, in our case this being a 300m length of 40mm diameter pipe buried 1.4m underground. This particular aspect of our build was a separate 'client item' from the main build contract so Debs, me, Stewart the digger driver and £60k's worth of band new JCB set to for four days of hard graft to get this pipe buried in the ground to in such a way as to absolutely maximise every joule of energy that could be sucked out of it .....which of course would be continuously be replenished by the sun. In effect, a huge solar panel!

In designing the collector system, we followed the heat pump manufacturer's (http://www.nibe.com/) advice on pipe depth, separaton and layout. Our supplier (http://www.ecoliving.info/) also offered advice on site and once certain of our plan, we got cracking! We ended up digging three 40m trenches, each 2m wide and 1.5m deep at 4m centres. We also imported 35 tonnes of sand to cover the pipe below and above to avoid the possiblity of damage from sharp rocks when backfilling and to ensure good contact with the ground. Bfore covering and backfilling, the pipe was pressure tsted and to finish off, fed into the house via the 'slow bend' duct pipes already built in to the floor slab.

All quiet on site...

It's now two weeks since the floor slab was poured with most of the ground floor plumbing and underfloor heating pipes in-situ. The planning and preparation work appears to have paid off as overnight rain reveals little ponding of water indicating we have a flat and level slab within the specified tolerance. All services are also now in place within the slab, having been 'introduced' to the inside of the building via pipework and ducts, with just the soil pipes to be revealed by tapping away the few mm of concrete over their sealing caps.

Little has happened since on site with the exception of the delivery of the timber frame sole plate material to be fitted in readiness for the main house frame, this being schduled for delivery w/c 29th October, although there has been much 'to-ing' and 'fro-ing' between frame supplier, builder, architect and client (us!) over minor changes to dimensions of components and materials.

In the meantime, we've put some more effort into landscaping works and have started to plant up behind the drystone faced retaining wall, this being almost complete bar coping stones (proving quite hard to come by!).

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.