Designing resilient homes
An increasingly important benefit of concrete and masonry buildings is the inherent resilience they provide to a range of environmental risks, particularly flooding and overheating. An overview of these topics and links to further information are provided below, along with information on fire, which is another resilience issue where concrete and masonry performs well. For a broad overview, the publication Building Resilience in a Changing Climate provides a range of articles on topics including: climate change; whole-life and sustainable industry performance; high-performance homes; and concrete credentials.
The occurrence of flooding in the UK has been particularly high in recent years and looks set to continue over the 21st century, with the latest predictions from the UK Climate Impacts Programme (UKCIP) suggesting a 16 percent rise in average winter rainfall for the North West, and an increase in the volume of rain on the wettest days leading to greater risk of flooding.
Concrete and masonry are flood-resilient materials, i.e. they absorb very little water, remain structurally stable (no warping/twisting) and will not rot. Their use in homes at risk of flooding provides a useful degree of adaptation to climate change, helping enhance the whole life performance of dwellings. Guidance on the use of these materials is covered in How to build flood resilient homes using concrete and masonry. Concrete can also provide a means of providing flood resilience in existing flood-prone homes, through the replacement of suspended timber ground floors with a ground-bearing concrete slab. This also offers a means of enhancing the thermal performance of the floor by eliminating draughts and incorporating insulation; typically saving around 10-15 percent in the energy needed for space heating.
BS 85500 has been published providing design guidance for buildings at risk of flooding and recommendations that highlight the flood resilience and resistance that can be achieved with concrete construction. Read more.
Overheating in homes is increasing for two key reasons:
- Summertime temperatures are gradually rising as our climate continues to warm. 2015 was the warmest year on record and the Met Office is predicting a temperature increase of around 3°C in the south of England over the 21st century.
- There is a greater tendency for modern, highly insulated and airtight homes to overheat as heat is more easily trapped.
The high level of thermal mass provided by heavyweight materials such as concrete and masonry can reduce the problem of overheating by absorbing and later releasing excess heat, with the aid of night-time ventilation. This is an increasingly useful benefit of construction materials with thermal mass which, alongside other measures such as shading, can help improve the resilience of homes to overheating. Guidance on thermal mass and how to use it can be found in Thermal Mass Explained. Technical information on Part L1A/SAP and the use of thermal mass in concrete and masonry housing is included in: Thermal Performance Part L1A 2013. Other useful publications on overheating include: Understanding Overheating - Where to Start published by the NHBC Foundation, and a broad range of guidance published by the Zero Carbon Hub, including a useful summary of design considerations called Solutions to Overheating in Homes.
Concrete and masonry materials do not burn, which reduces the risk of fire during a building’s life and also during construction. Read more.
However, fire performance can be an issue for timber structures, according to Government statistics (DCLG 2009). Improved fire safety measures during the construction of timber framed buildings are required whereas no special measures are required for masonry structures. In an open letter to the timber industry the HSE says: “All those making design and procurement decisions that significantly affect fire risk should consider and reduce the risk and consequences of fire during the construction phase through design”.
Architects and designers can reduce the risk of fire during a building's life and also during construciton, by specifying concrete and masonry solutions.
For more information on fire, download Concrete and Fire Safety.