Lexden Gardens - Ealing Council large-scale Passivhaus

An 8 storey 71-apartment project targeting Passivhaus certification is currently underway for the London Borough of Ealing. Members of the Passivhaus Trust team had the chance to visit Block B of the Lexden Gardens project whilst under construction. Block B, designed for over 55s, is part of a larger 188 home development, comprising 3 blocks, delivering a mix of social housing and affordable homes.

Lexden Gardens - Passivhaus Trust visit June 2025

A constrained London site, the project has had to overcome a number of challenges, unconnected to it being a Passivhaus, from tree retention to underground cabling and services. For a number of reasons the larger Block A is not being built to the Passivhaus standard, and so will offer useful data with which to compare building performance with the Passivhaus Block.

The London Borough of Ealing is committed to delivering exemplar new affordable homes, which tackle the climate crisis. The 71 new Passivhaus dwellings on the site are part of a programme of energy efficient new build homes which will introduce significant energy savings for residents, by maintaining a comfortable temperature all year round, in addition to providing an improved level of air quality. We look forward to the positive impact the new homes will have on residents’ lives when the new homes are completed next year.

Emma Osmundsen, Assistant Director, Housing Regeneration, London Borough of Ealing & Chair, Pasivhaus Trust

Lexden Gardens - Passivhaus Trust visit June 2025

The project is an early exemplar of the London Borough of Ealing's recent commitment to the Passivhaus standard for new buildings: "Ealing Council is committed to becoming a zero-carbon borough by 2030 (with new homes having to be zero-carbon by 2022). To achieve this target and ensure a baseline standard, Passivhaus certification is the baseline standard for all new buildings being designed in Ealing"

PHT members Beyond Carbon Associates are the Passivhaus Consultants and QODA Consulting is the Certifier on the project. It is the first Passivhaus project for contractor McLaren Consuuction.and architects KCA.

Lexden Gardens - Passivhaus Trust visit June 2025

It was really inspiring to see such a huge Passivhaus scheme underway on what is a challenging, tight site. And also to see the professionalism and enthusiasm of everybody working to deliver a high quality project. It really reminds us about why we do what we do!

Jon Bootland CEO, Passivhaus Trust

Key stats

Construction: Concrete frame with SFS infill
Number of homes: 71 2-bed apartments
TFA: 4454 m²
Start date: 2024
Expected completion: 2026
Certification: Aiming for Passivhaus

Lexden Gardens - Passivhaus Trust visit June 2025

For us at McLaren it has been a learning curve, but one that we have not shied away from. Changing our practice on site to Passivhaus has involved introducing 100 marginal gains rather than one major one.

Carl Adams, Operations Director, McLaren Construction

Construction

Lexden Gardens - Passivhaus Trust visit June 2025

The 8-storey block is being built in concrete frame, with SFS (steelframe system) infill from the first floor upwards.

Differences: Compared to the non-Passivhaus block A, the construction team has noted that Passivhaus Block B has required different detailing around the windows and greater attention to thermal bridges and penetrations.

Training: As it is the contractor's first Passivhaus, training has been central to delivering the project. Kick-off induction meetings are delivered to all subcontractors working on site, three weeks before commencing on site and then just before beginning on site. The initial training is delivered by Beyond Carbon and includes a presentation with photographic examples of good and bad practice on site. A significant proportion of the contractor's staff have also undertaken Passivhaus Tradesperson training with Coaction.

New air testing technology: Ongoing air testing has helped de-risk the process. Beyond Carbon has introduced an ultrasonic testing device that has been developed from systems used on leak detection on ships.

Data collection for certification: Quality assurance protocols have been stepped up to ensure data collection is undertaken consistently for Passivhaus certification.