Leeds Sustainability Institute

Building Fabric Performance



Build Process

New Build

Modern Methods of Construction


Under-Construction Testing

Post-Construction Testing

Forensic Performance Investigation

In-use Energy Consumption

Post-Occupancy Evaluation

Party Wall Bypass

Control Systems



Climate, Environment, Buildings & Energy

Joseph Rowntree Foundation Project Ref No. 805319

Final technical report
This technical report summarises the results and monitoring data from the Elm Tree Mews Field Trial carried out by the Centre for the Built Environment at Leeds Metropolitan University on behalf of the Joseph Rowntree Foundation (JRF) and Joseph Rowntree Housing Trust (JRHT). The Elm Tree Mews Field Trial research programme was funded under JRF project No. 805319. This report details the technical data from fabric performance tests carried out on the completed dwellings, site observations and photographic records of the construction process and an analysis of available site documentation and drawings. Performance testing included pressure tests, a coheating test, thermal imaging, temperature and air flow measurements and heat flux measurements. A design retrospective of those aspects of the design and construction process was undertaken by an assessment of available documentation and through a series of semi-structured interviews with key individuals involved with the development. The report also contains the results of 12 months in-use monitoring of the occupied dwellings and data on the performance of the communal heat pump system. This report should be read in conjunction with the main final policy report for the Elm Tree Mews project which is published by the Joseph Rowntree Foundation (Bell, Wingfield, Miles-Shenton & Seavers, 2010 - see http://www.jrf.org.uk/publications/low-carbon-housing-elm-tree-mews) The final policy report contains all the discussions, conclusions, recommendations and policy implications arising from the project.

Elm Tree Mews

This project sets out to provide a robust approach to the evaluation and monitoring of the Elm Tree Mews sustainable housing development in York. The development is being undertaken by the Joseph Rowntree Housing Trust, supported by the Joseph Rowntree Foundation and is intended to address the issues involved in creating low carbon, sustainable housing. The scheme makes use of a number of innovative features such as panelised I-beam wall construction, a communal ground source heat pump linked to an under-floor heat distribution system and solar thermal panels supplying some of the hot water demand. It is hoped that the development will have relevance for the design and construction of all housing schemes, including those undertaken by volume house-builders, and it is anticipated that the lessons learned will be fed back to the industry at large.

The scheme represents a modest step towards the UK government’s ambitious target for regulatory standards designed to achieve zero carbon new housing by 2016. Despite the general recognition that solutions exist for the construction of very low and zero carbon housing, there is considerable concern that many are untried and untested within the context of mainstream housing production in the UK. It is also clear that many schemes do not undergo comprehensive monitoring and evaluation. The research project is designed to ensure that as much as possible is learned about the approaches and systems used so that future schemes are able to benefit from the results.

The research project will consist of a retrospective evaluation of the design and construction process, performance measurements of the dwellings as constructed (compared with design expectations) and the monitoring of energy and other performance characteristics of the dwellings in use. The in-use monitoring will be conducted over a 12 month period and include the measurement of energy flows for heating and hot water together with the monitoring of electricity consumption for lights and appliances. Other data will be gathered on such things as internal temperatures, humidity, carbon dioxide levels and hot water consumption. The occupants of the houses will be given the opportunity to express their views and opinions on thermal comfort and other issues such ease of use of the heating systems.

Project Aims & Objectives

The broad aim of the proposed research project is to evaluate the extent to which the performance of low energy housing such as that at Elm Tree Mews meets that specified in the brief and as predicted at the design stage. This aim will be pursued through the monitoring of physical performance, review of design and construction records and the experiences of the dwelling occupants. As such, the project is an exploratory case study and although the normal limitations of such an approach will apply there are no real alternatives capable of delivering the level of understanding that is required. In the long to medium term the study will make a significant contribution to the cannon of low carbon housing field trial case studies that will both chart the progress towards low carbon housing and point the way to the next level. In meeting this general aim the project has the following principal objectives:

Objective 1: To evaluate predicted performance and the information and models used by the design and construction teams. To a limited extent this will include an analysis of the principle design and construction decisions and any site observations that are available.

Objective 2: To monitor the actual performance of the dwellings and their systems both as built/installed and in occupation.

Project Partners

Joseph Rowntree Foundation

Joseph Rowntree Housing Trust