Chris Stanley, housing manager at Modern Masonry, says overheating and emissions are as important to consider as fire protection in homes post-Grenfell.
The Hackitt report, published on 17 May following the Grenfell tragedy, has rightly filled many column centimetres already; here are a few more. It discusses the concept of layers of protection, particularly noting how “the use of non-combustible materials throughout the building” provides inherently higher levels of protection. While the scope of the report was limited to a focus on high-rise residential buildings (10 storeys and above), Dame Judith Hackitt made clear the intention was that recommendations could and should be more widely applied.
On 1 October, the government announced a ban on combustibles in the external walls of residential type buildings 18m and above, already widening the initial remit of the report. The implications of the ban are clear: structural elements that are within or form parts of external walls must be rated A1 or A2, the highest levels of non-combustibility. The ban begs the question: if a material presents a fire risk for buildings higher than 18m, why would it be safe for, say, 17.9m or 9.9m?
“If a material presents a fire risk for buildings higher than 18m, why would it be safe for 17.9m?”
Will potential buyers and investors be aware of risks or simply trust the regulations? Perhaps developers will judge it in their interest to go beyond minimum requirements and apply best practice across the board and not just to buildings taller than 18m? This may be a case of the market responding to what has long been seen in official statistics.
A second report that is shaping what we build is Heatwaves: adapting to climate change, by the Environment Audit Commission, published in July 2018. As a general point it raises awareness of how the problem of overheating will shape design in terms of ventilation and shading, but it goes further.
The commission expresses concern specifically about overheating and modular homes, and calls for government not to fund this type of construction. It is argued this is because modular homes tend to be lightweight, lacking the thermal mass that helps to protect them from overheating.
If the result is substandard living conditions, using lightweight offsite construction for social housing amounts to storing up problems for the future. On the open market, having to retrofit air conditioning in housing like this would be probable. The shape of what we build now should be informed by the need for good ventilation, shading and thermal mass to minimise likelihood of future overheating.
Development of a new standard from Europe on measuring carbon footprints has bust the myth that building in timber can help meet CO2 targets. The new rules for determining carbon footprint and environmental declarations of materials (BS EN 15804) will require manufacturers to declare what happens at end of life. During its growth, timber absorbs CO2 and stores carbon, but at the end of life this carbon is released as CO2 or in the form of methane, a more powerful greenhouse gas. The timber industry will have to declare the emissions which occur when timber products reach the end of its life.
While we seek to increase housing start numbers, what we build will be shaped by the need to build housing that is resilient to fire, reduces likelihood of overheating and meets the sustainability agenda without greenwash.