Could lightweight steel now offer a serious challenge to timber frame?

A look at Barbour ABI’s Panelised Modular Building Systems Market Report UK 2025–2029, stated that the total sector was worth a massive £1.26 billion in 2024, with timber frame accounting for around 70%. Light gauge steel framing (LGSF), by comparison, represented just 14%, with precast concrete accounting for a further 8%.

“That means timber currently has roughly five times the market share of LGSF within the UK panelised construction market, but rather than demonstrating that steel has failed to gain ground, the figures point to a potentially significant opportunity,” said Graham Dutt, Managing Director at Build with Steel, part of the well-established Forts Group.

Timber has already proved that developers and contractors are prepared to move away from traditional construction and embrace factory-manufactured structural systems. The question now is whether LGSF can persuade the market that steel offers advantages in areas such as precision, dimensional stability, durability and repeatability and whether those benefits can enable it to capture a larger share of a market that is already moving towards off-site construction.

The comparison becomes more interesting when the two materials are considered at a practical level. Timber frame has clear advantages, because it is familiar to the industry, supported by an established supply chain and understood by designers, contractors and installers. It has also benefited from decades of development in off-site manufacturing. For LGSF to take a greater share of the market, it therefore needs to offer more than an alternative material. It needs to demonstrate where steel can provide a better answer.

One of the most obvious differences is dimensional stability. Steel does not absorb moisture in the same way as timber, meaning correctly designed and protected steel framing is not subject to the same swelling, shrinkage, twisting or warping associated with changes in timber moisture content. For factory manufacturing, where components need to be produced accurately and then assembled to tight tolerances, that consistency can become particularly valuable.

There is also the question of durability. Galvanised steel framing is not susceptible to rot or insect attack, removing some of the biological risks associated with timber. That does not make steel maintenance-free, nor does it remove the need for correct detailing and protection, but it does provide a different set of characteristics for developers considering the long-term performance of a building.

Then there is the way the material behaves during manufacture. LGSF components can be produced to precise dimensions and formed into panels before reaching site. That means less cutting and modification is required during installation, while more of the work can take place in a controlled factory environment. For contractors dealing with increasingly tight sites and shortages of skilled labour, moving work away from the construction site can have practical as well as programme benefits.

However, the biggest difference is that steel can offer designers another level of flexibility. Build With Steel does not work exclusively with light gauge steel. Its approach combines cold-rolled LGSF, hot-rolled steel and hybrid systems, allowing different forms of steel construction to be used where they are most appropriate. That creates the possibility of designing a structural solution around the building rather than forcing the building to conform to a single construction system.

For example, where lightweight framing provides an efficient solution for the majority of a building, hot-rolled steel can potentially be introduced where greater spans, loads or structural requirements demand it. The two approaches can therefore work together rather than being viewed as competing systems.

This is important because the future of off-site construction is unlikely to be about finding one material that replaces everything else. It is more likely to be about selecting the right combination of materials and manufacturing techniques for each project.

That also changes the role of the company supplying the system. If design, engineering, manufacturing and installation are treated as separate activities, there is always the possibility that a problem identified at one stage will arrive at the next stage as someone else’s problem. A design may work structurally, but prove difficult to manufacture. A component may be straightforward to manufacture, but awkward to transport or install. A system may be fast to erect, but require extensive modification on site.

Build With Steel has based its model around connecting those stages, bringing design and engineering, manufacturing and installation together. The potential advantage is not just greater control over the steel frame itself. It is the opportunity to consider how the building will actually be made from the beginning.

“That is where the debate between timber and steel becomes much more interesting,” added Graham Dutt. “The question is not whether timber frame is a successful construction method. The market figures demonstrate that it is. The question is whether the next stage of off-site construction will see developers and contractors looking more closely at the characteristics of the materials being manufactured in those factories.”

“Timber has established the market and we recognise why. The opportunity for steel is to demonstrate where its own characteristics can deliver something different, whether that’s dimensional accuracy, durability, structural flexibility or the ability to combine different steel systems within the same building.

“We’re not asking developers and contractors to abandon a construction method that works. We’re asking them to look at the project and consider whether another approach could work better.”

With timber currently accounting for around 70% of the UK’s panelised modular construction market, steel has a considerable distance to travel, but it also has a clearly defined market to challenge and a growing set of reasons why developers and contractors might be prepared to take a closer look.