Progress...

Holiday Cottages Underway

So here we are starting a new and exciting adventure at East Cambusmoon. Three years ago we moved into our house, beautifully designed and immensely energy efficient, see here. We adopted a very low energy approach to the design and the construction detailing which focussed on significant levels of insulation, a high standard of air-tightness, strong passive solar design and a ground source heat pump for the heating and hot water, supported by a small PV array and mechanical heat recovery and ventilation. When we were at the design stage 4 years ago this approach was not widely taken but, even in the short time since we moved in, more people and architects are looking more broadly at how homes and buildings are managed environmentally. We joined the AECB and adopted their Silver Standard for energy use and carbon emissions. In truth the house has far out-performed this standard and even in the last particularly cold winter was warm all day every day at very low cost.

The ideal low energy house?

What we've set out to do at ECF is to build a house which will use 70% less energy than one built to current building regulations. Its timber frame construction detailing hasn't wavered too far from the 'norm' to present any major problems for a timber frame kit manufacturer, decent building contractor or building control, and the costs of going this 'extra mile' haven't been excessive to the extent that they will be paid back within a decade in terms of reduced energy costs.

Good weather = Good Progress

Wild Weather

Last night was a hideous experience. Scotland is suffering from a deep low pressure system with wild hairy winds which buffetted us yesterday evening, through the night and only this afternoon is easing. Gusts were 60-80mph and I didn't sleep more than 30 mins last night. The children did well sleeping til 3am and 5am before coming to find Mum (Dad being ensconsed in a London hotel!) We cuddled and snoozed, wondering if it could get much worse.

Saturday morning

Its just turned 9am on Saturday and we've taken a further delivery of Pavatherm Plus insulating board so the joiners can finish off the external insulation layer. There was relatively little activity on site yesterday as we were waiting for this delivery and the sliding door sets (3 off). The latter is now likely to be next week, but apparently has arrived from Penrith. I think these are around 6 weeks overdue and it's dissappointing that the windows from Norway arrived some four weeks ago and are now installed having been ordered at the same time as the patio doors! The main front door is also late and is sourced from Sweden.
The other happening this morning relates to the lame hen. Although it had a couple of better days in the past week it has now gone lame in both legs and is incapable of independent movement. So we had to wring its neck. I thought I could do this yesterday when it probably needed to be done but hen started clucking at me and I just couldn't so now that Steve has returned from working away he did the deed this morning. No, we're not eating it. There's no meat to speak of anyway but as we're not sure what's wrong with it it seems the best move....anyone with greater knowledge please advise!
We've got a fox prowling around. I need to repair/replace a bit of wire at the bottom of the gate to the hen pen before we go out this morning. There are fox prints on the top of the nesting box and on the roof of the hen house so we need to be sure to lock up quickly at dusk.I wonder if that explains the dead hares and rabbit the other week although I thought there would be more damage to the prey?
Rural living!......... we're off to Edinburgh today to see Santa, reindeer, lights, ice sculptures etc.

Wall Insulation

Thankfully we have plenty of storage space as the two main forms of wall insulation were delivered last week. The Rockwool Flexi 140mm batts are fairly standard, bulky, widely available and commonly used. The pavatex 'Pavatherm Plus' woodfibre board in the right of the picture is the non-standard element of our wall insulation. The latter is an insulating wood fibre board which is effective in reducing the U-value ie improving the thermal efficiency, in improving acoustic protection (not that we have any external noise problems!) and providing summer heat protection. It is used as an overcladding system for the timber frame in this application and will effectively 'block' most thermal through the frame and aid airtightness thus giving the best chance of this and the Rockwool insulation working at its best.

Portal frame arrives

Late afternoon yesterday saw the arrival of the prefabricated portal frames along with the brackets and bits to put them together. These are more than a week overdue and their late arrival has meant a temporary stop on site for a few days as nothing further could be done without them beyond the ground floor panels which are now in place .
However, things moved along again today as our main builder/project manager and two joiners started to the erect this steel framework into the gound floor panels. By the end of the day two of the three frames were in place and secured.
So why a portal frame? Well, this 1.5 storey house is very open plan internally with generous internal room heights (2.7m ground floor, 3.5m kitchen/diner, 2.9m first floor) such that the upper floor ceilings follow the roof line almost to the ridge, with a small loft space around 1.5m high. With this internal design it was tricky to use a (more conventional) truss system, so the portal frame is used to provide torsional stiffness to the building and carry a roof ridge beam, against which rafters will be supported for the roof. In effect, this is a contemporary take on a traditional method of roof construction.
In designing the roof we have also avoided the use of roof purlins (horizontal rafter supports) by using timber 'I-beams', each of which will span around 5m from eaves to ridge at a 45 deg. pitch and carry the weight of the slate roof supported only at either end. This not only keeps the internal structure clean and uncluttered, but their 352mm depth will be fully filled with insulation and their thin shear web minimises thermal bridging. The end result is a stiff, clean, super-insulated roof structure.
The down side to this constrcution has been additional labour/time and ultimately cost, but the end result should be worthwhile.

Wall plates installed

On Tuesday of this week the builders spent the morning fitting the wall plates (also called 'sole plates'). In timber frame construction these set out the plan of the ground floor layout and form the interface between the walls (both external and internal) and the ground floor slab/foundations.
The wall plates comprise timber of the same width dimension of the wall panels they support (ie. 140mm and 89mm), and are simply cut to length and laid on a bed of mortar (and damp proof course at the outside walls).
Whilst an apparently straightforward process, locating the wall plates in the correct positions is critical to the ultimate accuracy of the frame installation.
As an aside, this process also introduced a simple but effective airtightness detail to the building, in that the overhanging damp proof membrane (from under the slab) is folded back over the slab at the edges for later trimming and connection to the vapour membrane to be installed on the inside of the wall panels. Whilst not an essential detail (and usually omitted), this ensures an airtight and flexible linear floor/wall joint that should last through the first few years of the building 'settling' and drying out, a process often responsible for significant degradation of airtighness as cracks open between differing materials (eg wood/mortar) and thus worsening energy efficiency. Polythene membrane, being a flexible material, withstands this movement.
As an aside, airtightness is a key component to low energy building design alongside insulation, the minimisation of thermal bridges, orientation and glazing. Coupled with this it is essential to have an effective ventilation system to ensure good air quality inside - more on this and other airtighness details as the house takes shape.

End of week 3

Chooks

Our chickens have arrived! On Saturday we took ownership of 10 rescue hens from the Battery Hen Welfare Trust and they seem to be settling in well. The charity essentially comes to an arrangement with a battery egg producer to rehome hens which have reached the end of their maximum production cycle. They still have plenty of eggs to lay (the breed is Isa Brown which is a hybrid known for good egg production) and in our first 2 days we've had 10 eggs from them. Before too long we'll be selling them locally.
The hens have had 2 sunny days to get used to the big wide world, what a contrast to their previous living conditions. Some are distinctly more adventurous than others and are exploring their new environment, so far they have not ventured very far from one corner of the enclosed area. The children are throughly enjoying their new responsibilities and helping with looking after our new pets.On the building site - the men have finished laying the surface and rainwater run-offs into the lower field and the main house related activity is placing the 200mm of Jablite 70 polystyrene insulation board which is one of the key elements in keeping the house warm from the ground up. The sun is bouncing off the brilliant white polystyrene, its quite dazzling. Hopefully tomorrow the underfloor heating team arrive to attach the pipe circuits to the grid.