The climate is changing and buildings must change too if they are to withstand the weather of the future. Dr Stephen Garvin reports on the design, construction and maintenance issues that housing providers must consider – and budget for.
Hotter, drier summers, wetter winters, rising sea levels, higher winds, increased UV radiation. For housing providers, climate change means one thing – increased costs. Even if efforts to mitigate climate change are successful, there will still be significant effects on the built environment because it takes many years for some greenhouse gases to be removed from the atmosphere by natural processes.

The impact on construction is hard to quantify, but there will be significant costs if nothing is done. It will be harder to keep the elements out of homes, to stop them sinking into less stable ground and to protect them from flooding and storm damage.

The rising cost of maintenance may not be covered by insurers, though social landlords could reduce their premiums by improving building design. The consequences of not changing design standards will be expensive and wasteful, given that domestic projects typically have a 60-year intended service life – over the period in which significant changes to the climate are expected.

The process of revising standards and Building Regulations and issuing technical guidance is only now being addressed. But it is possible to reduce the risk and severity of future impacts by:

  • estimating future exposure to climate, based on current scenarios from the UK Climate Impacts Programme
  • making provision for the easier reinstatement of building fabric after flooding or gales
  • improving foundations in areas susceptible to subsidence
  • considering good design using thermal mass and natural ventilation to help control the overheating of buildings in the summer.

Walls

Walls must be constructed to withstand increased cracking and higher exposure to driving rain. Existing properties could be rendered to cut water penetration. Wider cavities in new buildings could also help insulation from the elements, while treating damp in existing properties could reduce heating needs in winter

Health and safety

Changes in winds, temperature and rainfall will mean increased hazards for builders working on homes. More working days could be lost to weather, although drier summers could compensate for wetter winters

Ventilation and heating

Hotter summers will mean more air-conditioning and, potentially, higher energy use. To reduce this, homes will need better natural ventilation and designed-in shading, such as trees. Designers should consider specifying denser materials to insulate houses from heat and cold, and should use more efficient and sustainable heating methods

Construction materials

Products may need to be adapted to new site conditions. For example, special additives could be added to concrete or mortar to counteract quicker drying-out in warmer temperatures. Storing and transporting materials could become more difficult and spoilage on site is likely to be more of a problem because of increased UV radiation, rainfall and wind speeds. Better facilities and processes will be required

Floodproofing

Increased winter rainfall and construction on flood plains could mean even more damage and disruption from flooding. In vulnerable locations, housing should be designed to accommodate more water ingress. They will also need to be more resilient, for example with water-resistant plasterwork, higher floor levels and no underfloor wiring. By the 2080s, the costs for all buildings will increase by more than £200m if nothing is done

Foundations

Wetter winters and drier summers will mean greater movement of soils and damage to foundations. Existing properties may have to be underpinned and for new build on clay soil, foundations should be 50cm deeper. Building work will have to take account of more mobile soil contaminants and ground gases at certain times of the year, and site preparation may take longer. If no action is taken, the cost of maintaining housing may rise by £200m-400m a year by the 2080s

Roofs

Increased wind speeds and rainfall mean roof tiles will have to take 5-10% higher loads. Meanwhile, eaves that overhang more could help protect from rain and wind. By the 2080s, the costs of repairing storm damage to buildings may have increased by £1.2bn per gale

Windows and doors

Plastics and timber joinery will not last as long, and glass will need better UV resistance. Windows and doors could be recessed with the detailing around them improved for better watertightness and insulation. If increases in temperature and UV radiation reduce the service life of PVCu windows from 20 to 19 years, the cost of replacement would rise by £2.4bn a year

Source

Housing Today

Postscript

Dr Stephen Garvin is director of BRE Scotland