Two houses are nearing completion at a small newbuild eco village in the northwest of Scotland. Achabeag township has planning permission for 20 houses, which will be clustered together on sloping land overlooking the Sound of Mull. Of these 6 are designated as affordable housing, but with an average build cost of less than £100K none are likely to break the bank.
The first two dwellings are different in appearance but both are built to a very high standard – with exceptional levels of insulation, minimal heating requirements, met by a woodstove and off-peak electricity, heat storage in a thermal floor slab, and solar thermal panels for hot water. The full-height (single storey) internal living spaces have Douglas Fir structural frames and masses of natural light from roof glazing. Aluminium clad timber windows are virtually maintenance free.
Commenting on the decision to specify the Hembuild system, Peter Smith of Roderick James Architects said: “Hembuild ticks all of the boxes when it comes to delivering sustainable properties, and the system is ideally suitable for what are two totally different styled houses but which fulfil the requirements of a scheme where the use of natural materials and environmental sustainability are the order of the day.”
Developed to deliver highly sustainable and energy efficient buildings, the product is based around a bio-composite building material made from hemp shiv (the woody core of industrial hemp) mixed with a lime-based binder – Tradical Hemcrete. This product, when used in conjunction with equally efficient hemp fibre insulation quilt delivers a groundbreaking combination of insulation and thermal inertia.
Building using the system creates a substantial smoothing out of temperatures, thus reducing peak loads and the capital costs of an M&E system. The building fabric partially takes over the regulation of the internal conditions using the passive properties of Hemcrete, instead of using the active properties of the M&E system. This creates the potential for reducing capital and running costs.
In addition to exceeding expectations based on conventional steady state U-values and standard thermal modelling, the process also sequesters carbon. This arises due to hemp capturing carbon dioxide during its rapid growth, whilst releasing oxygen back into the atmosphere. The carbon is then locked up within the walls of the building to give a carbon negative solution