EASTRIP LANE
A contemporary, energy efficient home in Wiltshire
"The trust we put in Greenheart has paid off and we have a building that not only meets our desire for the performance standards associated with Passivhaus, but actually exceeds them.
The actual living experience in the house has also exceeded our expectations."
The Site was on a significant slope, something we have grown quite used to, but which does tend to mean more concrete or cement based building materials than we would ideally want. That said we were mindful of embodied C02 and worked hard to keep that as low as possible.
It may seem logical on a number of levels to avoid any timber below ground level. We opted to use a structural timber frame right down to lower ground floor set against a cast concrete retaining wall/ delta cavity membrane drained via gravity through the ground slab. Careful detailing and WUFI modelling showed acceptable condensation/dampness risk. This was a lower embodied C02 alternative to the multiple skins of masonry cavity and tanking. Maybe a small saving in relative terms but it all counts!
The term ‘passive’ or ‘near passive’ is commonly used - often without real understanding of what it actually means. When we use the term, the heat demand, over-heating risk and primary energy consumption have been modelled (most often by Piers Sadler) using the PHPP package. The envelope design has been reviewed in relation to junctions, cold bridging and continuity of airtightness and insulation, and the levels required to meet Passivhaus standards have been broadly achieved. The provision of evidence, inspection during construction and involved process of certification have been avoided due to cost.
The client is an experienced self-builder with a healthy knowledge of the kind of techniques we have been honing over our 20-odd years in the industry. We love our clients to be engaged and interested and are always happy to learn from them, and vice versa. The client has been carefully monitoring this building since it was completed (see data below) and the outcome is in fact better than Passivhaus performance. A testament to our rigorous working methods across all projects. The PV array originally planned was omitted as it was considered a low priority - had it been installed, we would be looking at Passivhaus Plus performance.
It may seem logical on a number of levels to avoid any timber below ground level. We opted to use a structural timber frame right down to lower ground floor set against a cast concrete retaining wall/ delta cavity membrane drained via gravity through the ground slab. Careful detailing and WUFI modelling showed acceptable condensation/dampness risk. This was a lower embodied C02 alternative to the multiple skins of masonry cavity and tanking. Maybe a small saving in relative terms but it all counts!
The term ‘passive’ or ‘near passive’ is commonly used - often without real understanding of what it actually means. When we use the term, the heat demand, over-heating risk and primary energy consumption have been modelled (most often by Piers Sadler) using the PHPP package. The envelope design has been reviewed in relation to junctions, cold bridging and continuity of airtightness and insulation, and the levels required to meet Passivhaus standards have been broadly achieved. The provision of evidence, inspection during construction and involved process of certification have been avoided due to cost.
The client is an experienced self-builder with a healthy knowledge of the kind of techniques we have been honing over our 20-odd years in the industry. We love our clients to be engaged and interested and are always happy to learn from them, and vice versa. The client has been carefully monitoring this building since it was completed (see data below) and the outcome is in fact better than Passivhaus performance. A testament to our rigorous working methods across all projects. The PV array originally planned was omitted as it was considered a low priority - had it been installed, we would be looking at Passivhaus Plus performance.
Credits
Concept/planning design - s2 architects for Greenheart
Technical design - Greenheart
Structural design - Element Structures
Energy Consultancy/modelling - Piers Sadler
Concept/planning design - s2 architects for Greenheart
Technical design - Greenheart
Structural design - Element Structures
Energy Consultancy/modelling - Piers Sadler
Stats
Heat demand/heat load (modelled) – 15.6 kwh/m2/yr
Airtightness - 0.33 m3/h/m3
U-values (average W/m2k):
Wall 0.11
Floor 0.06
Roof 0.12
Openings 0.69
Heat demand/heat load (modelled) – 15.6 kwh/m2/yr
Airtightness - 0.33 m3/h/m3
U-values (average W/m2k):
Wall 0.11
Floor 0.06
Roof 0.12
Openings 0.69