Tiled floors with underfloor heating: A guide to minimising and repairing cracking
BRE (Building Research Establishment) is an independent, research-based consultancy, testing and training organisation, operating in the built environment and associated industries.
On 22 May 2015, BRE published Tiled floors with underfloor heating: A guide to minimising and repairing cracking (IP 6/15), by Rupert Pool and Tony Yates.
Warm-water underfloor heating (UFH) has become more widely used in the last 10–15 years. It provides background heat in large spaces and makes tiled floors much more comfortable to walk on in houses. Compared with traditional radiators, UFH provides a number of operational benefits because of the lower temperature of the circulating water. This can improve the efficiency of the boiler supplying the heat and allows the use of renewable energy sources such as ground source heat pumps.
However, cracking, associated with underfloor heating is a common cause of problems in rigid tiled flooring. BRE has investigated many cases where stone or ceramic tiles have been laid on screed only for cracks to appear in the tiles and along grouted joints within weeks of the heating system being operated. This is almost always caused by movement of the screed at a pre-existing crack or, in some instances, a ‘day’ joint in the screed. Even though this movement is just a fraction of a millimetre, it is sufficient to crack thick granite slabs. These cracks are normally the result of a poorly-designed floor screed (ie badly coordinated movement joints) or failure to properly commission the heating system before the tiles are laid.
This 8-page information paper sets out BRE’s experience of screeds that contain warm-water underfloor heating systems and describes how the risk of cracking can be minimised and how repairs can be undertaken. It is intended for architects and specifiers.
Its contents are:
- Introduction.
- Description of underfloor heating systems.
- Screed.
- Design of screed to incorporate underfloor heating.
- Problems that can occur.
- Crack-isolation systems.
- Commissioning the heating system.
- Checking a screed before the tiles are laid.
- Conclusions.
- References.
- Further reading.
Electric ‘undertile’ heating and proprietary ‘thin-screed’ underfloor heating systems are not dealt with.
[edit] Find out more.
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Construction industry reactions to the election result
ECA, CIAT and more to come as published.
At a Crossroads; Pathways to a Net Zero Future
Background to and summary of this key Renewable UK report.
Installing solar panels on listed structures.
The current and future global market dynamics of boilers
Significant challenges but adaptation to sustain for longer.
Designing sustainability and performance into buildings
Specifying and selecting sustainable resilient timber products.
Modifying wood to improve resistance to decay and movement.
A last minute, long look for built environment professionals.
The architecture of creative reuse. Book review.
Sustainable development global goals, history in progress?
"Unless we act now, the 2030 Agenda will become an epitaph for a world that might have been."
Mike Kagioglou FCIOB named CIOB President
'Sustainable Development Goals must be focus for construction'
BSRIA training; a look at what's on offer
From energy management to compliance training.
TESP video warns to beware of rogue trainers.
Highlighting the slippery tactics of non-approved providers.
New Building Safety Wiki launched
Boosting awareness and understanding of the new fire safety regime.
New playbook on AI in construction published by CIOB
How to get to grips with, and the best from AI.
Digital Construction Report NBS
BIM, cloud, off-site, immersive tech, AI, twins and sustainability.