The Hillsley Road site is directly adjacent to a motorway, which results in high levels of background noise which is in excess of the maximum standards set by the World Health Organisation. This is despite thick embankment tree planting. This problem is further exacerbated by the prevailing winds, which carry the sound from the motorway.

The design solution has included:

• Locating the buildings as far from the motorway as possible, along the north and east side of the site.
• Sealing the buildings as tightly as possible, negating the need for background trickle ventilation.
• Using heavy masonry construction to further dampen noise intrusion.
• Using conservatories to buffer sound from habitable rooms.
• Using warm roof construction in conjunction with additional layers of sound-bloc plasterboard in the upper floor bedrooms.
• Using high performance glazing with a larger air gap and laminated glass.

Consulting Engineers, Arup Environmental, have carried out an air quality survey on the site and predicted the future levels of pollution using computer modelling. The results helped to generate the site ‘contouring’ which enables the houses to be located on the least affected parts of the site and leaving the most affected spaces for access roads and parking etc.

In order to provide a clean and comfortable built environment, mechanical ventilation with heat recovery and filters have been incorporated and large internal recreation spaces are provided to compensate for the lack of usable external space. Here the project has utilised experience from the EU-Joule project “PV-VENT” and experience from this project has been incorporated in some of the used technical solutions.

The environmental aspects of this project are particularly relevant as Portsmouth City Council is one of 12 U.K. councils who are partners in a programme monitoring pollution levels aimed at achieving compliance with standards set out in the European Clean Air Act which comes into force in 2005.

Arup Environmental has prepared a separate report regarding air pollution from the M27 motorway that passes by the site. The study concludes that all of the dwellings will fall within the relevant UK and European air quality standards.

To reduce the noise level from the motorway the buildings have been sealed as tightly as possible, and this has been commissioned by blower door tests. Furthermore the heavy construction materials like bricks and concrete together with triple glazed windows have increased the sound protection.