Dr Jonathan Evans of metal envelope supplier Ash & Lacy gives a counter view to the consensus on offsite, saying that in the push towards MMC there is a strong case for some key design elements remaining onsite
20 years ago, I gave my most unpopular talk. At an event promoting offsite construction shortly after the publication of the Egan Report, I somewhat rained on the parade by stating that it would never take off unless one or both of two things happened. Either the Government should make it mandatory, or acknowledge there wasn’t enough skilled labour to build onsite.
In general, people have massively underestimated the benefits of not having a factory, sending materials directly to where they’re finally used, and only employing workers when they’re needed. Add to that the misplaced notion that main contractors would delight in their supply chains making no mistakes whatsoever, and offsite construction was really up against it.
A previous business of mine was a specialist rollformer, and I set up a company that supplied modular and unitised solutions.
We were very excited about it, and pursued many innovations, but like many others, I closed it due to well-meaning clients procrastinating so long that we couldn’t support the factory. It was crushingly disappointing, as anybody will know who has had to look people in the eye and tell them they have lost their jobs.
Despite this experience, it’s time to try again. We are established players in the load-bearing light gauge steel market and building envelope experts, and have just announced an investment in a new framing line and are setting up a new factory to assemble frames. Why? Because something feels different this time.
The inevitability of labour shortages
The labour shortage needs to be allowed to play out. This is what offsite construction has been waiting for 20 years. There is enormous latent capacity within the industry. It’s been a constant source of surprise and disappointment to me that we haven’t had more approaches from housebuilders about the supply of 2D and 3D frames.
We’ve been making pre-assembled frames for flat-to-pitch conversions for 30 years. I think the chronic shortage of labour is now possibly irreversible, and is reminiscent of what happened about 20 years ago with blockwork infill walling. The lasting legacy of our failed offsite enterprise was a successful SFS (Steel Framing Systems) business. SFS initially struggled to gain traction for the infilling of frame bays. It was faster and tidier, but there was no shortage of blockwork installers and Building Control inspectors were unfamiliar with it, demanding calculation packs for every job. They stopped doing that over time and as the popularity grew, there were fewer blockwork installers available, and very quickly SFS became the standard method. In about five years there was a complete turnaround, and it will never go back to the way things were.
The same thing looks set to happen with brickwork. If people see the emergence of quality brick slip systems, why would they spend their apprenticeship training for what might be a dying art? We began developing our brick slip system about five years ago.
As a super-critical person myself, I didn’t want anything that could be accused of being ‘fake’; I wanted a modern interpretation of the use of clay as a robust, durable cladding material. When developing all our systems, we always have offsite compatibility in mind.
We have firm ideas about what a successful offsite construction company should do, and I think you can predict those who will fail.
For example, our envelope business has shown us that it’s not necessary to standardise the componentry. When a building is surveyed, what looks like 500 identical cladding panels can often end up being 500 unique panels with just a few millimetres of variation. The key is to have a process that can cater for this – usually a digital order-processing and manufacturing environment. Each one of our cladding systems has up to 100 pages of internal design guide documentation associated with it, covering such things as span capabilities, connection locations, stiffener locations etc.
Furthermore, I firmly believe that the final finish should be applied onsite. This deserves an article in its own right, but in summary, it allows you to disguise the fact that the building is modular – it saves space, and gets the module out of the factory quicker and it allows for a degree of refinement of the aesthetic not possible in the factory. It also allows larger modules to be transported and reduces pressure on potentially performance-damaging efforts to make the external wall slender. You also don’t have to retain the envelope installers on your payroll.
Aces in their places
Finally, I think many companies would benefit from working in partnership with specialists in two key areas – the load-bearing frame, and the building envelope. If you buy an off-the-shelf load-bearing frame, in 10 years that’s what you’ll still have. By contrast, partnering with a company that does this as a core business puts you at the forefront of product and process technology.
For building envelopes, the case is even more convincing. External walls are extremely complex and subject now to more regulatory requirements than ever, possibly including a 15-year statutory defect period. Cladding systems fail much more frequently than people think, and they’re very expensive to rectify. Designing a ventilated system without cold bridges that doesn’t result in long term moisture problems is not straightforward.
Materials and finishes are changing all the time. Economies of scale mean that envelope specialists can offer you state-of-the-art solutions at reasonable costs. The envelope is what everybody sees when the job is finished and it defines the quality perception of the project, so it’s important to investigate the best solutions.
Dr Jonathan Evans is CEO at Ash & Lacy