Radical overhaul of construction industry needed if UK to have any chance, according to new research.

As I entered the construction site in England a decade ago, I was filled with excitement. This was a new state-of-the-art housing development. I was there to provide independent evidence as to whether the development stood up to its claims of superior energy performance: the construction company promised that the finished buildings would consume far less energy than the norm. As I put my high visibility jacket and helmet on, I noticed a TV crew unloading their equipment. This was clearly a high-profile site.

The site manager took me to the first house, where I was going to set up equipment for an air tightness test. I would use a large fan to create negative pressure in the building by extracting air from it, then use a pressure difference instrument to measure air flow through gaps and cracks in the building. A site operative with a mastic sealant gun told me: “I made it ready for you, mate.” The TV crew was right behind me – they were going to film me doing the test.

But as I started a routine visual inspection of the house, I noticed a pea-sized hole in one of the window frames – it turned out that the operative hadn’t done a very good job after all. As a result, the air tightness test had to be postponed and the TV crew got an extended coffee break until we found the man with the mastic gun. 

This incident is representative of my career. I’ve very rarely come across a building that actually lives up to its claims.

Now, my new research reveals that even the best aspects of the UK’s current building plans don’t go nearly far enough. We have found that due to embodied carbon emissions – the emissions that derive from making building materials and constructing houses, rather than heating and powering them – only building all new housing using naturally grown materials with negative embodied carbon will allow the UK housing industry to be net zero by 2050.

Numerous UK local authorities have declared a climate emergency and are committed to constructing buildings to net zero carbon emissions, in many cases aiming to reach this by 2030. But the current UK building regulations do not even require new buildings to achieve operational zero emissions – that is, emissions from building use. Embodied emissions – emissions from making and using building materials – are not even on the radar of the local authorities. 

The problem is that there isn’t enough joined-up thinking. Builders are trained how to build, but are not trained to know how their work affects building energy performance. Government initiatives are introduced by one department to reduce energy consumption and discontinued by another department to enable enough houses to be built cheaply, with no consideration for unintended consequences. Building standards are not ambitious enough and take years to change. Developers do not want to exceed these standards, as this would increase their costs and reduce profits. The industry is fragmented and operates in silos. 

Quality of workmanship

Even when intentions are good and houses are designed to the best specifications, lack of training standards in construction mean they often aren’t built properly.

I started working in the construction industry while doing my PhD on the energy performance of a new ‘solar village’ in Bournville, Birmingham. The houses in this new village were what we call ‘passive solar’: they had been extremely well insulated and were designed to admit heat from the sun through large, south-facing glazing, and to retain warmth within the concrete floor slab and the dense concrete blocks in the walls. This heat, slowly emitted, warmed the houses, reducing the need for a central heating system much of the time.

As the desired effect is only achieved in an airtight building – so that heat cannot escape the house – my team tested the air tightness of a demonstration house. We were surprised to find that the test instruments were telling us that the building was not airtight at all – there was a significant air leak. The search for the air leak took us to the attic space, where we found that heating pipes running from the solar hot-water system on the roof into the house were routed through unnecessarily large and unsealed holes. We sealed the holes and carried out a successful air tightness test. The year was 1985.

This has happened to me many times over the years. Buildings are rarely as airtight as construction companies claim them to be. This is often due to large holes drilled for small electricity cables; window frames peppered with holes; air leaks through loft hatches and door thresholds; air leaks through electrical sockets in walls and through holes for pipes in the floors.

Big house builders consider that it’s too onerous to improve air tightness and some argue that this may be why the regulations haven’t changed for years.

Meaningless assessments

Carbon dioxide emissions came on the horizon in the first decade of this century as something that needed to be better controlled in buildings.