New Eco Dwelling, Harrowbarrow

This scheme has aimed to utilize SIP (Structural Insulated Panel) construction, structurally insulated panels contribute to code for sustainable homes through excellent thermal performance, air tightness and limited cold bridging. The idea of a sedum roof has been consistent throughout the scheme. Initially solar panels were going to be incorporated within the scheme but due to the roof type (green roof) along with the orientation and nearby trees the site would not have suitable conditions for the solar PV panels to perform.

The successful layout of this project has been quite challenging due to various restrictions. As there is already an existing access onto the site it would be pointless creating another fenestration in a different location. This left the entrance fixed with the development boundary not encompassing the entire site the space for development was limited.

As the site is located over 30m from the nearest mains drain, a non-mains drainage strategy was required. The client has opted for a composting toilet which separates out the solids and liquids. To deal with the solid waste a hot bin composter will be utilized and liquids/greywater are going to be treated in the WHALE system (Water from Households Above-ground Living Eco system) which works in a similar way to a reed bed system. The WHALE system is designed to clean and purify greywater, which comes from sinks, Dishwashers, washing machines and showers etc… in a typical household situation. It uses specially selected plants to organically remove the micro-organisms and pollution from the waste water to supply clean non-potable water for use in watering plants and washing cars, clothes and dishes. Once the greywater is purified, the collection tank will hold up to 180 litres in a greenwater tank with the overflow from this connecting to the soakaway.

The dwelling is to utilize passive slab foundations(Insulated Foundations), SIP construction, Sedum roof, non-mains gas, composting toilet, WHALE greywater treatment system, Rainwater harvesting, Heat Recovery Ventilation (breather window) and a wood burner.

The dwelling is a single storey and with a roof pitch of 9 degrees retains a low ridge height (3.3m). The hedges surrounding the site are high and well established almost completely hiding the new development.

Oak sleepers are being used around the site to create retaining walls. Three sides of the dwelling are to be clad in vertical, board on board green oak. The remaining side, to the rear of the property, will be in a fire resistant material and finished in undulating, free form render.

The dwelling is using a green roof and with an offset ridge, the offset ridge has mainly been utilized for construction purposes aligning with internal walls to decrease the span of the ridge beam.

Building Type

Eco and ContemporaryHousing

Services Provided



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