REBUILDING A 17’th CENTURY FARMHOUSE An abridged copy of this article appeared in the Ecology Building Society Newsletter, November 1997, Issue Number 13, Restoring Ecologically.

For the last two and a half years, a North Yorkshire couple have been rebuilding a semi-derelict 17th century long-farmhouse. Ecology Building Society members Graham Smout and Ellie Owen were keen to repair the building and refurbish it in environmentally sound ways, incorporating energy saving insulation and recycled materials such as timber. In the beginning one half of the building was just habitable, but there was no adequate heating, a serious damp problem, prehistoric plumbing and sanitation, and some very peculiar room layouts. Until 1993, the rest of the building had been used by a farmer as his ‘shippon’ or cattle byre and hay loft. The roof of this section was near to total collapse and the walls were not much better. After moving in, we virtually ‘camped indoors’ with our two children while building work went on around us for the best part of a year and a half. (This is not an activity recommended for relaxation, but is entertaining as it involves lots of cups of tea and many packets of biscuits and plenty of conversation at early hours of the day). Restoring the house has been a huge effort, mentally, physically and financially, but the end result is a restored building which is comfortable to live in as well as making a smaller impact on the environment. For some years we had been interested in methods of environmentally sound construction and energy conservation. We were fortunate to know of Steve Brook, a Keighley builder who is a member of the AECB (ASSOCIATION OF ENVIRONMENTALLY CONCIOUS BUILDING). Steve became involved in planning the renovation with the help of David Rushworth, a retired building site foreman joiner & manager.

Problems and setbacks. We moved into the house at Easter 1995. From then until late summer, we were drawing up plans and getting them approved. There were last minute additions as the building inspectorate suddenly required U values, (heat loss ratio) for the rubble stone walls which are up to 1m thick. There are no reliable references for this kind of wall, so David Olivier of Hereford firm, Energy Advisory Associates, kindly supplied an estimate and the plans were passed. Insulation. At the outset, we decided high levels of insulation would be key factor in reconstruction. All the walls are internally insulated with a dry lining system. Two methods were used.

On the upper floor, we specified recycled timber studding lined with 15cm of mineral wool and a foil backed plaster board. The ground floor walls are mostly finished in plaster over an internal concrete block skin with an insulating sandwich of slabs of polystyrene and air gaps. Steve Brook was keen to eliminate cold bridge effects at window and door openings. Cold bridges are caused by rapid heat loss where poorer insulators such as timber, stone and glass, meet heavily insulated walls. The condensation caused by a cold bridge interface is probably the most likely cause of rot in timber framed windows. The theory is that if the cold bridge is reduced, there is no reason why timber frames in softwood should not last as long as more popular hardwood. So at the points where wall meets window frame, 3cm foil backed insulation board made by Kingspan and equivalent to 10cm of rockwool, was fitted to eliminate the cold bridge at window and door reveals. A vapour barrier and foil backed plaster board completed the wall construction. In the roof and below the floor, we included as much mineral wool insulation as could be managed, this being at least 12" in the loft space. Under the traditional stone slates, was a layer of Tyvek roof membrane which works in much the same way as the Gore-Tex material used to make outdoor gear. ( It lets out condensation, but keeps out rain)

Damp Treatment. Some of the main walls are below ground level, so venting and draining ducts were built into the insulation sandwich to deal with water penetration, while on the outside, a water proof membrane and French drain were created to divert any ground water. All walls were affected by severe rising damp but due to reservations about the long term effect of silicone based chemical injected damp proof methods, it was decided to use the Remtox mortar system. This involved drilling lots of holes at 25cm intervals in the rubble stonework then injecting a damp proofing mortar. With the thickness of the walls being more than 1m thick in places, this was a major operation. The drill holes were saturated with water then, the rapid setting damp proofing mortar followed. As it dries, various salts from the mortar migrate into the surrounding stone work creating a damp barrier.

Timber Work & Treatment. Much of the existing timber in the building was so badly attacked by woodworm that it had no structural strength left. It simply had to be taken out and burnt as fuel. To replace all this with new timber would have been both expensive and an unnecessary drain on a valuable resource. Recycled pitch pine timber from a demolition site has been used to reconstruct the main roof trusses, floor joists and wall studdings. Exposed 12" square pitch pine beams are used to support the first floor. To reduce the impact of chemicals on the environment, Boracol wood preservative from Remtox was used on all timber. This boron (borax) based substance eliminates woodworm but has no known impact on animal life in the various food chains, including mammals such as bats and birds. At £75 for 5 litres, Boracol seems pricey, but 5 litres goes a very long way, leaves no residual smell and the area treated is soon habitable again . A plain wood finish was appropriate in many places in the house but finding a suitably benign timber finish was difficult. O. S. Transparent Wood Wax finish is a completely non toxic covering.

Windows and treatments. All the original windows had been attacked by wet rot. The building specification did not allow the use of either tropical hardwood or Upvc frames. As the problem of cold bridging had been tackled, it was considered frames in softwood would be acceptable and last longer than frequently predicted. To reduce costs, the frames used were supplied straight from a local joinery in Keighley.

Glazing To reduce heat losses via glazing, it was decided to use Pilkington ‘K’ glass specification or better, as it reflects back more heat back into the rooms than traditional double glazing. Windows and doors were painted with the O.S. system of natural oil based, non toxic, low odour paint. Some very exposed exterior surfaces were finished using a microporous system and internal surfaces with water based acrylic paint. Energy consumption. The house is in a high position but there is some shelter from the hillside to the North. An unusual feature of the building is a 1metre thick weather wall to the West. Perhaps this was an addition to the original house to try and reduce the impact of the prevailing westerly winds. Our choice of heating system was a dilemma, but in the end we opted for an automatic oil fired central heating boiler for space heating and hot water. Research showed the preferred alternative, LPG gas to be far more expensive to purchase and run as mains gas is not available. Oil fired boilers of the balanced flue type are fast approaching gas in levels of combustion efficiency. The option of fitting solar panels has been left till a later date. The insulated areas of the house require minimal input from the oil powered boiler and radiators with thermostatic shut off valves are almost always off. As one of the aims of the project was to reduce energy consumption, electric lighting at the farm uses 95% low energy bulbs. Ironically, we have discovered that in the 1940’s, a local engineer built and erected a wind generator on the Western gable of the thick weather wall, the remains of which were clearly visible during restoration of the roof. It is long term aim is to generate electric power again. Any one with ideas or experience in power generation is welcome to contact us via the EBS.

Water Supply During the summer of 1995, the spring supply to the house failed. Analysis showed the water to be heavily contaminated with surface water containing sheep dip residues and E-coli. A new pure underground spring source about 300 metres from the house was discovered, and a storage tank and automatic pump installed. This gives us independence from mains treatments and charges and a reliable supply in all weather conditions. We have also provided for grey waste and rain water to be diverted for garden use in the event of another dry spell. The original sanitation was completely inadequate consisting of a tiny septic tank connected to the house by leaking pipework. When the inevitable system overload happened, we rapidly had to decide on a larger septic tank and drain system. The outfall from this is planted with a reed bed to help absorb toxic products.

Completion. At the time of writing, the renovation is virtually finished barring a few cosmetic details. It is a comfortable and warm building with lower than average running costs, despite being in a remote location. There are many people, firms and individuals, whose help has enabled us to complete a successful project, including the EBS. Thanks to them all.

Product listing. Insulation. Roof space; 35cm mineral wool. Tyvek roofing membrane. Floor void ; 15cm mineral wool. Wall void; 15cm mineral wool. Window reveals ; 3cm Kingspan Board. Linked wall dry lining systems; Foil backed plaster board, 15cm mineral wool, vapour barrier. 20cm thermalite block, polystyrene /air gap 15cm sandwich. Timber treatment. ‘Boracol’ boron based fluid for woodworm by Remtox. O & S oil based paint. O& S Wood wax finish. Leyland Acrylic Paint Leyland Micropourous system Timber Supply: Recycled pitch pine beams, sorted and sawn to appropriate sizes in roof trusses, floor joists, wall studding and decorative features. New timber used for floor boarding and roof spars. Damp treatment: Remtox mortar injection system. Solid Building Materials: Wherever possible, recycled stone has been used for wall, window and roof construction. Concrete has been used for foundations and structural work. Concrete blocks are used in interior walls and concrete lintols bridge doorways and windows. All solid materials were sourced close to our location to avoid excessive transport costs & energy consumption. Plastics: These were not used unless alternatives could not be found, e.g. in electric cables and waste pipework. There is still an issue to be addressed here. Graham Smout & Ellie Owen.

CONTACTS ECOLOGY BUILDING SOCIETY 18, Station Road, Cross Hills, Keighley. UK Tel; 0345 697758 email info@ecology.co.uk ASSOCIATION OF ENVIRONMENTALLY CONCIOUS BUILDING, Windlake House, The Pump Field, Coaley, Gloucestershire, GL11 5DX. United Kingdom telephone: 01453 890757 WORLD WIDE WEB Site; http://members.aol.com/buildgreen/index.htm STEVE BROOK; BUILDER (member of AECB), 56, Manville Road, Keighley. Telephone; 01535 662294

White House Farm; Graham Smout & Elaine Owen; email- gpsmout@nildram.co.uk

Last updated on 8th July 1998