Designing for the Future: Moisture, Mass Timber, and Smarter Buildings

Nick Clifford: Moisture-Proofing Timber from the Start

🎙️ Principal Technical Consultant at TSUK | Former Timber Consultant at BM TRADA

Nick Clifford opened the discussion with a deep dive into moisture mitigation for mass timber projects, specifically CLT (Cross-Laminated Timber). As someone who spends much of his time investigating moisture damage in timber buildings, Nick brought technical clarity and urgency to the topic.

“CLT’s many sustainability benefits do come at a cost. We have to pay a bit of extra attention to these wood-based products to make sure that we avoid risks associated with moisture exposure.”

Nick emphasised that effective moisture risk management isn’t a task for the construction site alone; it begins at the design stage, continues through construction, and must be accounted for during building operation.

Key Moisture Risk Areas:

• Flat CLT Roofs

“If your project has a large flat roof in CLT, I might ask you: whose design guidance are you following? Because Stora Enso and others don’t support flat CLT roofs—it’s all shallow pitches.”

• Rainwater Outlets & Wet Rooms
  “A rainwater outlet leak rotted panels down through several storeys. A metre away? Bone dry. That’s why sensor placement needs to be targeted.”
  

• Sensor Strategy
  Nick urged teams to design with sensor access in mind, ensure they are not “value-engineered out,” and include an alert protocol that is handed over with the building.

“You need to include a moisture alert response procedure. What happens if you get a ping from a moisture sensor? Building users need to know. Otherwise, what’s the point?”

From upstands to sloped roofs and embedded sensors, Nick’s message was clear: early design decisions dramatically reduce downstream risks and costly repairs.

Mark Tant: Quality Assurance from the Contractor’s Perspective

🎙️ Construction Consultant | Former Managing Director, Wates Construction

Next, Mark Tant tackled the issue from the contractor’s lens, focusing on why moisture management is so often overlooked and how it can be incorporated into better construction practices.

“The truth is, the industry lives under a series of guidelines. Very little is actually mandated.”

While standards exist for fire and structural safety, moisture management hasn’t received the same regulatory attention, despite being a leading cause of post-completion issues. Why? According to Mark, it often comes down to culture, cost, and short-term thinking.

“Quality often falls down the agenda. We perform during the job, but forget the legacy of what we leave behind.”

Eye-Opening Data from the Field:

• 99% of timber buildings show moisture during construction
  
  
• 9 out of 10 flat roofs leak before completion
  
  
• 60% of those leaks persist after handover
  
  

These stats aren’t from theory; they come from real-time monitoring, including data collected by Tector.

“What if you could prove your roof didn’t leak? Moisture sensors let us do that. That’s real quality assurance.”

Visuals vs Data: A Real-World Leak Story

Mark shared a compelling example: a moisture sensor detected a spike on December 15. Visual inspections followed. Contractors claimed it was fixed. Yet every time it rained, the sensor showed moisture spiking again until three months later, when a proper fix finally resolved the issue.

“We rely on visual inspection and believe the leak is fixed. The data tells a different story. That’s the power of real-time moisture intelligence.”

His conclusion? If we can demonstrate that we’ve built dry, we don’t just reduce rework and cost, we improve reputation, client satisfaction, and long-term performance.

Dominic Lion ACII: Moisture Risk from an Insurance Perspective

🎙️ Executive Director & Sustainability Champion at Gallagher

Closing out the session, Dominic Lyon shifted the focus to how insurers perceive moisture risks and how those perceptions shape premiums, coverage, and even project viability.

“Water damage—not fire—is the #1 cause of insurance claims in buildings. But fire gets all the headlines.”

With deep experience in complex construction risk and as chair of the UK Government’s Timber in Construction Insurance Working Group, Dominic offered a sobering view: insurers are only just catching up on how we build today.

“Grenfell was the moment insurers realised they didn’t understand how we’ve been building buildings for the last 10–15 years.”

Insurers are now paying close attention to how clients manage risk, especially for innovative methods like mass timber. The good news? That scrutiny opens the door for smart design teams to stand out.

How Moisture Management Impacts Insurance:

• Buildings with leak detection systems often receive better terms.
• Real-time sensor data improves claim defensibility.
• Proactive moisture management helps achieve insurability for mass timber, which remains a sticking point for many carriers.

“It’s not just about reducing loss. It’s about showing that you understand your risk and have systems in place to manage it.”

Dominic also connected moisture control to broader ESG goals, noting that well-monitored timber buildings support sustainability commitments and signal seriousness to investors, insurers, and regulators alike.

From Blind Spots to Best Practice

Moisture risk isn’t a niche concern. It’s not “just a timber issue.” It’s something that affects everyone across the built environment—from architects and engineers to contractors, developers, asset managers, and insurers.

And the truth is: we know better now.

We know where the weak points are. We know that most leaks start during construction. We know that digital tools exist to spot problems early, to improve quality, and to build trust.

The challenge now is cultural, not technical.

It's about moving from "we hope it's dry" to "we know it is."

So, whether you're breaking ground on your next project or reviewing performance on your last, the question isn’t just "Did we meet spec?"
It’s: "Are we doing the right thing for the long-term durability of this building?"

If the answer isn’t clear, now’s the time to rethink how we design, build, and care for the structures we leave behind.

Moisture may be silent, but when we ignore it, the damage speaks volumes.

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