The Lancaster Cohousing group is situated near Halton on the River Lune near Lancaster. They have recently completed 41 custom build certified Passivhauses including flats and houses, and a communal building along with lots of communal facilities. There are some existing industrial buildings on the site which have been improved and converted.
This is an example of communal custom build with extremely high ecological standards. Apart from being certified PassivhausSee more on the Passivhaus standard. The PassivHaus Institute has pioneered a standard for low energy buildings. It includes very low energy usage and ways of achieving this. The word is derived from the idea of buildings which are fundamentally low energy and passive solar heated rather than using extra gadgets to heat them. See Passivhaus for the UK branch of the organisation. it attains the (now defunct) CSHCode for Sustainable Homes. A delightful tool for assessing how green a home is. Unfortunately now withdrawn (2015) by this short sighted government. level 6 standard and Lifetime Homes"Lifetime Homes make life as easy as possible for as long as possible because they are thoughtfully designed. They provide accessible and adaptable accommodation for everyone, from young families to older people and individuals with a temporary or permanent physical impairment". See the Lifetime Homes page and the Lifetime Homes Foundation web site.
The site is long and narrow, running alongside the river, and quite steeply sloping and south facing. This resulted in several terraces with walkways between. It also meant that solar energy was viable.
transport and buildable area
Because the residents wanted to cut down on car usage there are very few roads or parking spaces. An agreement was reached with the planners that only six cars would be owned by the members of the group and this led to more space being allowed for building on rather than parking. Half a dozen of the residents own cars and parking spaces out of necessity but otherwise cars are shared, including an electric one which derives its energy from solar.
Included in this planning agreement was that residents could not park their cars within a couple of kilometers of the development. (Planners are keen to avoid the situation where a developer might try to provide too little parking space resulting in residents parking on the highway).
There is a cycle route between the cohousing and Lancaster and there are excellent facilities for storing and working on bikes (along with quite a few canoes).
energy production and saving
While Passivhaus design aims for extremely low energy use, a small amount still needs to be supplied to each house and Lancaster Cohousing has utilised both solar (thermal and 89kW pvPhoto Voltaic. referring to the generation of electricity from sunlight) and biomass (woodchip boiler) so far and is in the process of constructing a 150kW hydro power generator which will be powered by the river Lune.
The woodchip boiler is situated in one of the existing old industrial buildings which were present on the site when the group bought it.
The woodchip fuel is sourced locally and supplied by the company which installed the boiler. (It is important that wood chip fuel is of the correct grade and moisture content. There have been several cases in the past where damp wood chip has caused considerable problems by jamming in the supply auger).
Solar energy from rooftop pv panels is partly used to power the group’s electric car.
The hydro electric turbine installation is being constructed further upstream on the river Lune
Each house/flat has a single radiator which is sufficient for a high degree of comfort due to the huge amount of insulation. Ventilation is by means of heat recovery units which bring in a constant flow of fresh air which is heated from the warm outgoing air (MVHRMechanical Ventilation with Heat Recovery. This is usually a double fan arrangement which extracts stale air from the house and sucks in fresh air at the same time. As the warm stale air is blown out, heat is extracted from it and passed over to the cool incoming air by means of a heat exchanger. With the latest technology, over 90% of the heat can be recovered. (see Passivhaus standard) )
design and construction
A handful of original members bought the site from a building company which had gone bust and then the design of the whole site was worked out with the architect. The construction is mainly concrete blockwork with OSBOriented Strand Board based internal linings although the south facing walls with the large windows were constructed as a timber frame. To keep withing budget there is a good deal of repetition in the house designs and to make the best use of the rather difficult sloping site a considerable amount of leveling of land had to be done using gabionsThese are wire cages (often about a meter cube) filled with stones. You see them protecting river banks, acting as retaining walls and, more recently as walls in buildings.
Detailing is to quite a high standard and of course windows are triple glazed and doors and windows extremely well insulated and well sealed. Window frames are PVC which may be controversial to those who would like to see oil production phased out. Rain water goods are galvanised steel.
In line with the cohousing ethos, the houses themselves are slightly smaller in size than might normally be the case because things like spare bedrooms, washing machines, storage areas etc. are provided in the shared areas.
Apart from the shared communal area there is a workshop, a children’s inside play area, an area to store bulk purchased food, a cycle store, a laundry, an office and post area (individual letter boxes in house doors are generally so drafty that they would spoil the high levels of air tightnessA measure of how leaky a building is to air. In other words, how draughty it might be. There are now standard fan pressure tests to check how air tight a house is and the Building Regulations have minimum standards for all new houses (L1A – Conservation of fuel and power in new dwellings (England)). A much higher degree of air tightness is covered by the Passivhaus standard required for the passivhaus standard). Also shared guest bedrooms.
Architects are ecoarc
There is a Guardian blog
The two main books on cohousing are both excellent and well worth reading partly because of the range of examples they give on the continent and the US.
The other book
covers what is something of a relatively recent departure from the central idea of cohousing, (which was a fairly balanced community in terms of age range).