Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 222222
Loughborough University

Centre for Innovative and Collaborative Construction Engineering


Eirini Mantesi


Developing a new evidence base for high thermal mass buildings


Aggregate Industries, PS Sustainability Ltd & Dr Jeremy Harrall


Professor Jacqui Glass
Prof Malcolm Cook
Dr Christina Hopfe

Dr V Smedley
Dr J Harrall

Director of Research
Professor Stephen Ison

Research Period

2014 - 2018

Developing a new evidence base for high thermal mass buildings

Company Background:

Aggregate Industries provide overall leadership for this EngD project and host the Research Engineer at Bardon in Leicestershire, within its Sustainability Team. Aggregate Industries is a leading construction materials supplier in the UK with a turnover in excess of £1 bn. It supplies a range of aggregates, asphalt, ready-mixed concrete, precast concrete and contracting services. Innovation, research and development are core to its approach for delivering more sustainable products and services. www.aggregate.com

Current state-of-the-art:

There is a significant R&D opportunity around the role of materials in contributing to energy demand reduction in buildings, principally through the effective deployment of thermal mass. There is also an important research agenda around low carbon construction and decarbonising the whole built environment.

While the phenomenon of thermal mass and hence the contribution of heavyweight materials to overall building energy performance and comfort levels is thought to be reasonably well understood, a trend towards super airtight and lightweight building construction appears to be leading to increased instances of problems of poor indoor air quality and overheating. This is particularly the case in buildings with extended occupancy patterns such as domestic and residential properties, many of which are occupied by people from low income and/or vulnerable groups. The rising cost of energy and the low rate of renewal of old, inefficient building stock in the UK is also exacerbating a growing problem of fuel poverty.

Designers of low carbon, passively designed buildings maintain that good ventilation combined with sufficient thermal mass is important to reducing energy consumption and maintaining comfortable conditions. Hence, building performance research should be focusing on these types of solutions to ensure that end users have access to the best quality living environments, but a number of developments warrant specific attention.

New evidence from extensively monitored building projects designed by SEArch Architects suggests that very high thermal mass structures actually behave differently to design predictions and can offer substantial energy savings in practice. In the absence of mechanical means for heating and ventilation, SEArch’s buildings are sustaining narrow internal ambient air temperature ranges of eight degrees Celsius with a small additional supplementary heat load of 9kWh/m2. However, these datasets require more intensive analysis to really understand this phenomenon and be able to generalise to other settings or building typologies.

There is also new evidence that the thermal mass in insulating concrete forms (ICF) walls does in fact have a much more significant effect on indoor temperatures and comfort conditions than is commonly expected. Building performance monitoring of the SHINE-ZC project in Derby has indicated that the concrete core of the ICF wall is not as thermally isolated as might be conventionally expected. This is a very important phenomenon to investigate because it means that standard calculations and building design modelling software are based on a faulty premise and buildings may be over or under designed as a result. Also at the SHINE-ZC project, a pilot seasonal thermal storage solution is producing intriguing data that suggests that seasonal storage has a role to play in managing comfort levels and can improve the overall effectiveness of renewable heating solutions, but this requires substantial further analysis and testing.

Furthermore, no research to date has explored the role of changes in moisture levels over time on the thermal mass properties of any type of construction. This is particularly relevant in heavyweight construction, as a concrete or masonry wall could experience both wetting and drying cycles over its lifetime. Hence, there is a refreshed need to investigate the physical behaviour of high thermal mass and derive lessons from these new datasets and hence create an evidence base of validated and robust information on low energy, high mass structures.

Aim and Objectives:

The aim of this project is to create and exploit a new evidence base for high thermal mass construction.

The objectives of the project include:

  • To critically review existing knowledge of the physics of thermal mass in buildings and the design and construction ‘performance gap’
  • To examine and quantify the monitored performance of high mass buildings
  • To derive new interpretations about the behaviour of thermal mass elements
  • To produce valid and robust results that can be applied in practice to help reduce energy consumption in buildings
  • To deliver recommendations to Aggregate Industries that inform its R&D and product development programmes.

Proposed Research Design and Methods:

This project is grounded in fundamental building physics and building engineering and will focus on building typologies with extended occupancy patterns, such as domestic, multi-household residential and commercial office properties. As such, it requires a programme of research that entails extensive data analysis, modelling, some physical testing and validation.

  • A literature review on the physics of thermal mass will be carried out alongside site visits to a series of high mass, low energy building projects to familiarise the researcher with the subject area.
  • This will set the context for a major phase of analysis of building performance data that has been logged and captured within those projects.
  • The Research Engineer will be required to analyse parameters such as heat flux, temperature differences and core temperatures from high thermal mass structures, using dynamic thermal simulation software, such as IES, ESP-r or TRNSYS.
  • Mathematical modelling and building simulation will permit greater analysis of these datasets than has previously been possible and should create new understandings of the monitored data, particularly in respect of their transferability to other building typologies.
  • Emergent findings would need to be validated and therefore some physical modelling and testing would be anticipated, to be carried out in the building energy research laboratory of the School of Civil and Building Engineering. This may include direct comparisons with lightweight envelopes.
  • Derive recommendations for new product development and ways in which further research might unfold, e.g. through investigation of design implications and prototyping of control systems.

It is expected that outcomes from the research will result in high quality published journal papers (e.g. Proc. Institution of Civil Engineers (ICE); Energy and Buildings) and conference papers (e.g. International Conference on System Simulation in Buildings; CIBSE and ASHRAE events) and would also inform on-going building projects being undertaken by the sponsoring companies.

The Research Engineer would work alongside another based at Aggregate Industries, Aaron Lang, who is working on the socio-technical and commercial aspects of high mass building solutions. The two projects are expected to work in collaboration to ensure that the business obtains scientifically valid and commercially competitive outcomes. The Research Engineer would also be expected to participate in presentations about his/her research to academic, commercial and other audiences.

Expected Benefits and Outcomes:

Participating and supporting this EngD will help Aggregate Industries to access new data and ultimately develop new value-added products and services to help reduce energy consumption in buildings. It will create:

  • Valid and robust data analyses that can underpin the commercial proposition for new high mass products and construction methods.
  • New understandings about the behaviour of high thermal mass that can inform building design and thereby improve comfort and reduce energy bills for occupants.
  • Published analyses of previously unexploited datasets that can inform subsequent research in the area.
  • New construction techniques, building methodologies and/or new product development ideas to achieve guaranteed levels of performance, e.g. i.e. ‘no overheating assured’.



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The Centre Administrator
Loughborough University
LE11 3TU

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