Here's How We're Doing

A flurry of snow, beautifully clear skies, sunshine and a hurricane all in 24 hours. Work on site with the two holiday cottages has progressed well and we're pleased to dust off the blog to show you some updated photos.
The view here of the cottages from the east shows the two bedroomed stone building on the left of the photo and the four bedroomed one on the right. The larger cottage is finished partly in white render and will also have larch clad areas on the unfinished section you can see. The brown material visible is Pavatherm which is a compressed wood fibre board used as an external insulation material. That area will be larch clad which will age fairly quickly to a mellow silvery grey. The materials used fit very well with the local vernacular and have also been used on our own house. The red sandstone is well over 150 years old and is typically 2feet thick. The official naming of the two bedroomed cottage...

We commissioned a name stone which is placed high on the west gable of the cottage. I'm really pleased with the way the whole building looks now, the cleaned up stone is looking all the more splendid in the winter sunshine. For a quick reminder of how it looked check here.

Both cottages have access ramps and at grade entrances for wheelchair users. They also have plenty of big windows to maximise those views of our beautiful surroundings, being strong on energy conservation the windows are Argon filled double glazed with sustainable timber frames.The interior of The Old Dairy. The living space is a full height room with high level windows as well as ground floor sliding doors to the patio. You can just see the pipe which will serve the wood burning stove on the left.
The living space of the larger cottage is impressively large and, again, has big windows for big views.

The view below is of the Campsies (to the south-east) from one of the bedrooms.

One kitchen....

Solar thermal panels on the south facing roof....

and photovoltaic nicely generating electricity to serve both cottages.

Progress...

... has been fairly rapid during the long days of a Scottish summer. Since pouring the floor slabs the timber frame has gone up in a matter of weeks, with work now starting on building up the old dairy's stone walls another 400mm to roof eaves level so our guests will have plenty of headroom upstairs!

Construction design is similar to the house, using an insulated timber frame clad with woodfibre board on the outside for extra insulation and to reduce thermal bridging. This keeps the wind out and, with the help of fancy tapes and membranes on the inside, the heat in. Heating is to be from a ground source heat pump and solar thermal panels, with solar PV offsetting electricity use. Inside we just have underfloor heating on the ground floor which will keep things cosy during the chilly winter months!

Over the next couple of months we should see the roof windows in and the roofs slated, then hopefully, the windows and doors will have have arrive so the cottages can be wind and watertight before the cooler and wetter months...roll on Autumn!

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 main difference between the projects are that the house was a new build and the holiday cottages are a conversion of two very tired farm buildings. Notwithstanding our intentions to replicate some of the approaches we took with a brand new building we are very aware that we are renovating an old dairy and byre and will certainly be retaining the architectural features the buildings; the red sandstone which was quarried locally, the arch over the doorway and the window recess with wooden lintel. Here we are creating two adjoining holiday cottages, one of two bedrooms, one of four. As we are in Loch Lomond & Trossachs National Park we hope that some of the year-round visitors to this stunningly scenic area might like to come and stay in the cosy warm luxury of our holiday cottages. As you can see we're just starting the conversion works and we'll do our best to record the journey on this blog.

The building story so far has been one of rapid change. The roofs have fallen in and the rubble cleared out; in the stone building (which will have two bedrooms) the 'hole' for the sliding patio doors has been punched through and the stone stockpiled for reuse; in the larger unit, which was brick built in the 1950s, the walls collapsed so extra blockwork and labour will be required; floor levels were equalised as existing floors sloped. Then we get into the first stage of serious insulation - the floor. So much heat is lost through the floor, don't waste it!

In the past week 200mm of polystyrene and polyeurathane insulation boards have been laid throughout the buildings and on top of this will float 30 tonnes of steel and concrete in the 4 bedroom unit and 15 tonnes of the same in the two bedroom unit. Before the concrete is poured the underfloor heating pipes are installed; this is done by fixing the pipework (large diameter polythene pipe ideal for use with heat pumps) to the steel reinforcement mesh with tie-wraps. This approach works well with ground source heat pumps which have lower operating temperatures than the more frequently used shallow tray form of underfloor heating. The concrete provides the thermal mass necessary to stabilise the temperature and keep those cottages lovely and warm when needed.We're using Anderson Floorwarming for the underfloor heating, hot and cold water systems, installation of the ground source heat pump and solar. We are happily working with the same builder, subcontractors and architect as we did on the house so its nice to see familiar faces back on site.

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.

In essence, we have built to a standard which is accessable now by most contractors and self builders which is around 5-6 yrs before its time if the UK Government is to fully implement its Code for Sustainable Homes (CSH) strategy, on which this building should come in at around 3-4 on a scale of 1-6. There is clearly some distance to go from this to 'zero carbon', so what represents the 'optimum' for 'Level 6 living', the magical zero carbon level required by 2016 for all new homes?


Well, the same principles apply, namely...

• building orientation to maximise solar gain in winter, spring and autumn whilst avoiding overheating in summer


• high levels of insulation around the entire building envelope


• high levels of airtightness coupled with heat recovery ventilation


• highly insulated and well sealed doors and windows

...but for CSH level 6 the wall insulation would need to be increased to >300mm (from our 200mm), roof insulation to >450mm (from our 350mm) and windows to be triple glazed krypton filled units with insulated frames and glazing spacers (vs. our argon filled double glazed units). This would result in a building which could feasibly rely on the heat given off by its occupants and collected though its windows to keep it at a comfortable temperature without having to introduce a heating system. Construction might rely on internal masonry/concrete walls to store heat and keep a steady internal temperature, with the insulation fixed to the outside of this.

On the face of it quite simple, but a seriously long way from what the UK housebuilding industry is used to. Roll on 2016.....there is a lot of catching up to do and mindsets to be re-programmed.

Good weather = Good Progress

Afterwhat has seemed a long spell of dreich weather, the sun finally came out today and the slaters made significant progress on the roof, now about 75% slated. Inside the joiners completed the poythen vapour membrane work on the 1st floor such that we now have a near airtight house.

As I have mentioned before airtightness is an essential element in low energy housing; it allows the insulation to work properly, prevents draughts and ensures that ventilation can be properly controlled. The old adage 'insulate tight - ventilate right' has to be the watchword for the eco-selfbuilder, and if planned and implemented properly, will go a long way to achieving significant savings in energy even before considering renewable energy systems and high efficiency boilers.

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.





As daylight arrived there was debris all over the place but no obvious significant damage. The house has little building paper remaining and the roof sheets were off which means water penetration yet again but these are remediable. A friend phoned to see if we needed rescuing which was very thoughtful. The notable shock was that the hen house was on its side about 4metres from its previous position. I opened the door with trepidation expecting some unpleasant scene and can thankfully report no casualties. Poor devils must have got a bit of a shock. We've put the house back on its feet and replaced the bits and bobs.



This afternoon the storm has abated but there are some very active clouds with an awful lot of wind still blasting around. If it gets worse then we're staying at a friend's house tonight!

After refixing some of the building paper the joiners were inside today continuing with the roof insulation. The barn load delivered the other week is rapidly disappearing and the house is getting 'cosy'.

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.



Today in the glorious sunshine the joiners made a start on the south gable. Also the suppliers of the Pavatherm board visited to discuss the product and its installation with the guys on site as well as Steve and I. Last winter when we were looking at specification/design issues for the house (that seems such a long long time ago!!!!!!) we had concern about it being an appropriate material in the wet West of Scotland as the insulation should be fixed dry but we were reassured by architects who had used it on self-builds in Scotland. The AECB also provided contacts through their forum which was beneficial in this sort of decision. The joiner had not used the product before but by the end of a very productive day he rated it very highly and enjoyed working with it.




On other matters the larch cladding arrived this afternoon but the timber frame manufacturer has sent the wrong profile so that will need to be replaced. Hopefully they will do this quickly. Also or architect has sent through revised details for the porch so that can go ahead now.



Slates have also arrived. The electrician and the chimney man are due tomorrow. Bathrooms and the 3 really large fixed and sliding windows are due on Wednesday. Bathrooms should have arrived last week but didn't...more chasing!

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

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.

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.