Concrete emits carbon when it is made. Steel emits carbon when it is made. Timber does the opposite — it stores carbon while the tree grows, and keeps it locked in for the life of the building. Unlike concrete and steel, CLT is a regenerative material— not just low-carbon, but actively part of a biological cycle that, if managed well, sequesters more than it emits. That is a fundamentally different proposition, and it changes how we should think about specification.
The numbers are significant. On average, almost 43% of greenhouse gas emissions are avoided when reinforced concrete structures are substituted with mass timber alternatives (source: MDPI). CLT panels are prefabricated off-site, bolted together on site, and — crucially — can be disassembled and reused at end of life if connections are designed correctly. The adhesive question matters here: polyurethane glues used in most CLT production today make panel separation difficult. The next frontier is designing CLT assemblies that can come apart as cleanly as they went together.
There are caveats. Sustainable forest management and FSC certification are non-negotiable — if trees used for CLT are harvested unsustainably or not replaced, we lose the steady drawdown of CO2 that CLT promises (source : MIT Climate Portal). And awareness in the sector is still patchy: a survey of European experts in timber engineering rated awareness of CLT among construction managers and owners as low or very low (source : Chathamhouse), with fire safety misconceptions and insurance barriers still slowing uptake.
So: are you specifying CLT or other mass timber products on your projects? What are the real barriers — cost, regulation, supply chain, client resistance? And are there manufacturers, engineers, or contractors in Europe doing this particularly well that others in this community should know about?