Residential and Sustainable Design

Private Client - Harpenden

Deep retrofit of a 1960s detached house in Harpenden and the addition of a small rear extension.

This project is aiming to meet the EnerPHit Plus (Passivhaus) retrofit criteria as well as going 'gas free' by using an air source heat pump and harnessing renewable energy with an entire roof pitch dedicated to solar pv. 

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The existing brickwork walls will be externally insulated using wood fibreboard which will be finished with a painted lime render and the curtain walls will be removed and replaced with new highly insulated timber I beam walls with cellulose insulation and clad in western red cedar or grey tiles to match the rear roof slope. The rear single storey extension will also be constructed in this way and finished with either render or timber cladding. The existing ground floor is also being removed and replaced with a new highly insulated slab with underfloor heating.