Challenges of Passivhaus in new build residential

At the recent UK Passivhaus Conference, Footprint attended a talk on new build residential projects in the UK. The talk was in three sections; planning, procurement and construction.

Gokay Deveci began by speaking about his his move towards Passivhaus design over the course of several projects during the last fifteen years.

The first project he described was the Van Midden House in Aberdeenshire, a six bedroom house completed in 1999 for £50,000. This house was his first look at minimal heating methods, just using a centrally placed Aga stove.

Gokay Devici, A'Chrannag (Crows Nest), Rothesay, Isle of Bute photo:

Moving on, he described A’Chrannag; a social housing scheme on the Isle of Bute, completed in 1994. This scheme aimed to reduce household energy bills by up to ninety percent. However, Gokay found that there were large variations in energyuse between tenants, really highlighting that it is the users of the buildings that consume energy and not necessarily the buildings themselves. It is about educating people in how they live in and use low energy buildings.

He went on to describe his Model D house in Aberdeenshire, completed in 2009. The project cost £120,000. Its focus was to achieve close to Passivhaus standards using only locally-sourced materials.

Gokay concluded with the more well known Passivhaus project, Tigh Na Claddach which can be found in the AJBL, here.

In taking us through these Scottish projects, Gokay highlighted the need to adapt designs to local climatic conditions. Aberdeen is on the same latitude as Bergen and Gothenburg, yet they follow the same regulations as England. The climate is obviously rather different. Passivhaus is a method of designing which allows for this adaptation. It can act as a good design tool for investigating how a building is suited to its surroundings and how these will affect energy use.

According to Gokay, the Passivhaus standard  makes him ‘confident that he is leaving the next generation a good building’. He described Passivhaus as more than just an energy standard but as a quality assurance standard. It is a method of building which has been tried and tested for over twenty years.

James Banner of Bailey Garner then spoke about procurement, using Sampson Close, a project of 23 new build houses and flats in Coventry for Orbit Homes, as a case study.

They decided to go for Passivhaus early in the design process. James spoke of the challenges in pricing Passivhaus projects, as many contractors do not understand the principles of Passivhaus, and therefore it is difficult to price projects on a design and build basis. Despite this, he remains hopeful for the future of Passivhaus in the UK. The homes were constructed from timber frame sourced from Germany, as there were concerns that UK companies could not guarantee the high levels of air tightness required. The German frames were air tested before they left the factory. Windows, doors, and blinds were pre-installed in the factory to guarantee the airtightness. Windows and doors were Passivhaus certified products from Internorm. Read the Footprint post on their manufacture, here.

Many of the products used in the project had to be sourced from Europe, a problem many UK projects face. James pointed out numerous issues associated with sourcing abroad:

  • exchange rates
  • translation issues
  • PI insurance
  • contract and payment terms
  • UK registration of European companies
  • issues with building regulation compliance
  • treatment of timber is not necessarily standard practice in other European countries
  • health and safety translation issues
  • replacement parts are not readily available in the UK.

This highlighted the lack of UK experience in the supply chain. In the UK, Passivhaus is in its infancy and there is currently not enough drive to catch up with the rest of Europe.

James Pickard of Cartwright Pickard complimented James Banner’s presentation by speaking  about his project, Sulgrave Gardens in LB of Hammersmith and Fulham, a mix of thirty houses and apartments for Octavia Housing Association, previously covered on Footprint here.

It began on site two months ago and is comprised of four blocks:

  • Block A - six three-storey terraced houses
  • Block B - a five-storey apartment building
  • Block C - a five-storey concrete framed apartment building
  • Block D - four three-storey mews houses.

Block A has a simple form, reflecting the Victorian architecture of the surrounding streets. The building is constructed from timber SIPs panels with brick cladding. A slate roof integrates photovoltaics and solar thermal hot water.

Block B is constructed using a concrete frame with SIPs panels. This method was chosen to achieve fire and acoustic requirements.

For Blocks C and D, they have decided not to go for Passivhaus certification. This is due to the wall to floor ratios which would make Passivhaus standards difficult to achieve. However, they still tried to design the buildings to the same standard as the other blocks, in order to achieve high levels of energy efficiency.

James said that they had found Passivhaus ‘quite challenging’, partially due to having an awkward and restrictive site, and partially due to it being their first Passivhaus project. Costs have worked out at approximately six percent higher than just designing to building regulations.

We then heard about the experience of Passivhaus from a contractors perspective, from Neil Smith, of Holbrook Timber Construction.  Neil described his work on bere:architects Larch House at Ebbw Vale.

by Laura Mark, past AJ sustainability intern

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