The CLT System
Mass timber construction for mid-rise, commercial, and architecturally ambitious projects — with the structural depth to go where SIP cannot.
Cross-Laminated Timber (CLT) is an engineered mass timber panel that delivers structural performance comparable to concrete and steel, with a dramatically lower carbon footprint. Panel Haus offers CLT as a complementary system for projects requiring greater spans, exposed timber aesthetics, or multi-storey structural flexibility — with integrated insulation options for complete performance assemblies.
average embodied carbon reduction vs. steel & concrete
[1] Younis et al. systematic review (27 studies)
m² of CLT installable per day
[2] Structurlam / Sustainable Lumber Co.
projected global CLT market by 2033
[3] IMARC Group, 2024
global CLT market CAGR 2025–2033
[3] IMARC Group, 2024
What is CLT?
Cross-Laminated Timber is manufactured by stacking layers of solid-sawn lumber boards in alternating perpendicular directions — typically at 90-degree angles — bonded with structural adhesives to form a rigid, load-bearing panel. This cross-wise arrangement significantly enhances strength, rigidity, and dimensional stability in both axes of the panel.[4]
The result is a structural material with a strength-to-weight ratio that rivals concrete and steel. One cubic metre of CLT weighs approximately 400 kg — compared with 2,700 kg for an equivalent volume of concrete — while delivering the same structural resistance.[5] This reduced dead load translates directly into lighter foundations, lower structural material quantities, and faster installation.
CLT panels are prefabricated to project specifications using CNC machinery accurate to ±0.2 mm,[6] with all openings, services penetrations, and connection details pre-cut before delivery to site. The panels arrive ready to assemble — like, as one structural engineer described it, “giant Lego blocks.”[2]
CLT buildings can presently reach up to 18 storeys — as demonstrated by the UBC Brock Commons tower in Vancouver, completed in less than 70 days[7] — with regulatory pathways now permitting CLT structures up to 18 storeys under the 2021 International Building Code and equivalent national codes.[8]
Why SIP vs. traditional construction?
SIP construction offers measurable, independently verified advantages over conventional timber framing — across build time, labour, energy performance, and lifecycle cost.
Mineral wool batts or semi-rigid boards bonded or friction-fitted to the CLT panel. Recommended for projects with elevated fire performance requirements, high acoustic targets, or mixed-use typologies where sound transmission between tenancies is a compliance consideration.
Thermal conductivity
~0.033–0.040 W/m·K
Fire classification
Non-combustible (Euroclass A1)
Sound absorption
NRC up to 1.00
Moisture resistance
High — dimensionally stable when wet
Best for
Multi-storey, commercial, mixed-use
Natural wood fibre boards or batts providing a fully timber-based, breathable wall assembly. Ideal for projects targeting low embodied carbon, Passive House performance, biophilic design, or sustainability certifications that reward bio-based material content.
Thermal conductivity
~0.036–0.050 W/m·K
Vapour permeability
High — breathable, moisture-buffering
Embodied carbon
Negative (biogenic carbon stored)
Thermal mass bonus
High — reduces peak temperature swings
Best for
Residential, Passive House, NCC 7-star+
Why CLT vs. concrete and steel?
CLT is increasingly positioned not as a niche alternative, but as the primary structural material of choice for projects where carbon performance, installation speed, biophilic design, or seismic response are decisive factors. A systematic review of 27 peer-reviewed life cycle assessment studies concluded that CLT can reduce the carbon emissions of large buildings by approximately 40% compared with traditional materials.[1]
Lower embodied GHG emissions vs. reinforced concrete
A review of 62 peer-reviewed LCA articles found that, on average, nearly 43% of GHG emissions are avoided when reinforced concrete structures are substituted with mass timber alternatives. Individual project comparisons show reductions ranging from 20–70% depending on design and biogenic carbon accounting.
[9] Younis et al. (2023), systematic LCA review, Buildings (MDPI)
Cost savings vs. steel and concrete
A case study analysis by Waugh Thistleton — architects of the world’s first tall CLT building — found overall project savings of approximately 15% by switching from conventional materials to CLT. A separate US performing arts centre comparison found CLT to be 21.7% more economical than the steel and concrete alternative.
[10] USDA Forest Service citing Waugh Thistleton; [11] Laguarda Mallo & Espinoza (2016), ResearchGate
Installation speed
More than 1,394 m² of CLT can be installed per day. In real-world terms, UBC Brock Commons — an 18-storey hybrid mass timber tower — was structurally complete in less than 70 days, with zero safety incidents recorded during the entire mass timber installation phase.
[2] Structurlam; [7] NC State University College of Natural Resources (2022)
Seismic and structural resilience
A seven-storey CLT building was tested on the world’s largest shake table in Japan and survived 14 consecutive earthquake simulations with almost no structural damage — including simulated forces equivalent to the 1995 Kobe earthquake, which destroyed more than 50,000 buildings. The IBC now permits CLT buildings up to 18 storeys.
[7] NC State CNR (2022); [8] International Building Code 2021 (Types IV-A, IV-B, IV-C)
Carbon sequestration in structure
CLT panels actively store biogenic carbon captured during the tree’s growth — approximately 1 tonne of CO₂ equivalent per cubic metre of timber. In a documented CLT housing project in New Haven, CT, the timber structure stored around 2,757 tonnes of CO₂eq — partially or fully offsetting the building’s construction-stage emissions.
[12] Hemmati et al. (2025), Sustainability (MDPI) — 340+ Dixwell CLT housing case study
Adoption in eco-building projects
Reports indicate that nearly 52% of eco-friendly building projects now incorporate CLT in their structures, driven by green building certification requirements, government incentives for sustainable construction, and the material’s dual role as both structure and exposed interior finish.
[13] Reanin Research (2024), Cross Laminated Timber Market Report
The carbon case for mass timber.
The building sector was responsible for 37% of global final energy-related CO₂ emissions in 2022.[14] Embodied carbon — the emissions locked into a building’s materials before it is ever occupied — is increasingly the primary target for regulatory and voluntary carbon reduction programmes. CLT addresses this directly.
"Mass timber buildings demonstrated a GWP reduction in the range of 39–51% compared to functionally equivalent reinforced concrete buildings — even without biogenic carbon sequestration benefit included."
When biogenic carbon sequestered in the timber is accounted for under recognised LCA methodology, the reductions are substantially larger — up to 69.5% lower embodied carbon emissions than equivalent reinforced concrete, and in some whole-building scenarios, net-negative embodied carbon at the construction stage.[16]
Source: Hemmati et al. (2025), MDPI Sustainability; Younis et al. (2023) systematic review [9][12]. Values are indicative ranges across reviewed case studies. Individual project outcomes will vary.
As a note of integrity: the carbon benefits of CLT depend on sustainably managed forest supply chains. Panel Haus sources CLT from certified suppliers where harvested forests are replanted, maintaining the circular carbon cycle that underpins CLT’s climate value. FSC or PEFC certification is standard in Panel Haus supply chain specifications.[17]
Where CLT is the right system.
CLT is the preferred Panel Haus system for projects that require greater structural span, multi-storey height, exposed timber aesthetics, or institutional/commercial grade performance. It complements — rather than competes with — the SIP system, and Panel Haus projects can combine both systems within a single building envelope.
Multi-storey residential
4–18 storey apartment, build-to-rent, and social housing projects where carbon targets, NCC compliance, and build speed are all decision criteria.
Commercial & office
Exposed CLT ceilings and structure are increasingly specified for tenant attraction, NABERS/WELL ratings, and corporate ESG commitments.
Education & civic
Schools, libraries, and community buildings where biophilic environments, fast delivery during school holidays, and long design life are requirements.
Hospitality & mixed-use
Hotels and mixed-use towers where exposed timber aesthetics differentiate the project and CLT’s acoustic mass addresses floor-to-floor sound transmission.
Industrial & warehousing
The largest industrial mass timber structure in North America — a 41,800 m² facility — used CLT, establishing precedent for industrial-scale applications.
Hybrid CLT + SIP
CLT primary structure with SIP infill panels for walls and roofs — combining CLT’s span capacity with SIP’s airtight, insulated envelope performance in a single build system.
CLT vs. SIP: choosing the right Panel Haus system.
Panel Haus offers both systems because no single engineered panel is the right answer for every project. Use this guide as a starting point — your Panel Haus specification team will advise on the optimal configuration, including hybrid approaches.
Mid-rise, commercial & long-span
- Project is 4+ storeys or has large structural spans
- Exposed timber interior finish is part of the design intent
- Carbon reporting or NABERS/LEED embodied carbon credits are required
- Acoustic performance between floors and tenancies is a compliance target
- Seismic design category requires additional lateral performance data
- Project is institutional, commercial, or civic with long design life
- Insulation strategy needs to be customised (rockwool vs. wood fibre)
Residential & light commercial
- Project is 1–3 storeys: residential, light commercial, or industrial
- Maximum thermal envelope performance is the primary driver
- Fastest possible structural framing cycle is required
- Site labour availability or cost is a key constraint
- Budget is tightly managed and cost-per-m² is the lead metric
- NCC energy compliance pathway with minimum complexity is needed
- Project does not require exposed structural timber aesthetics
How CLT installation works.
CLT construction follows a design-led prefabrication sequence. Because all panel dimensions, openings, services penetrations, and connection details are resolved digitally before manufacturing commences, the on-site phase is an assembly exercise — not a construction exercise. This distinction is at the root of CLT’s speed and safety advantages.
01
BIM design and structural engineering
Project drawings are developed into full BIM models. Every CLT panel, connection, and service penetration is resolved in the digital model — including insulation configuration — before a single piece of timber is cut. Integration of Building Information Modelling with CNC fabrication achieves panel accuracy to ±0.2 mm.[6]
02
Factory fabrication with insulation integration
CLT panels are manufactured and — where the project specifies rockwool or wood fibre configurations — insulation is bonded or fitted at the factory. Panels are labelled and sequenced for installation order. CNC cutting of openings and steel connector plates occurs at this stage, eliminating on-site cutting waste.
03
Site preparation and foundation
Because CLT structures are approximately one-sixth the weight of equivalent reinforced concrete per m², foundation systems are typically smaller, faster to construct, and require less material. The structural tolerance of the foundation must be precise — millimetric variations in the slab can create coordination issues during panel assembly.[5]
04
Crane-assisted panel assembly
Panels are crane-lifted and secured with steel connectors. More than 1,394 m² can be installed per day by a team of 6 technicians.[2] Because the structure is stable and load-bearing as soon as panels are placed, following trades can begin work floor-by-floor without waiting for the full structure to reach roof level — compressing the overall programme.
05
Building envelope and fit-out
Once the CLT structure is assembled, cladding systems, glazing, and MEP services are installed. Where exposed CLT ceilings and walls form part of the interior finish, no further structural surface treatment is required — reducing material and labour in the fit-out phase and contributing to the biophilic interior environments that CLT buildings are architecturally known for.
A rapidly scaling global technology.
The global CLT market was valued at USD 1.74 billion in 2024 and is projected to reach USD 3.85 billion by 2033, reflecting a 9.2% CAGR.[3] Europe currently accounts for approximately 45% of global market share, supported by strict environmental regulations and decades of timber building tradition. North America is experiencing the fastest growth, driven by rising mass timber adoption in sustainable housing and commercial projects and supportive updates to the International Building Code.[18]
Australia is an emerging CLT market with strong growth fundamentals — an acute housing shortage, tightening NCC energy performance requirements, and state and federal commitments to embodied carbon reduction. Research by Dylan Cazemier at the University of New South Wales conducted a direct financial comparison of a CLT apartment building versus a concrete and steel equivalent constructed in Australia, providing an early evidence base for the material’s commercial viability in the local market.[19]
Europe’s share of global CLT market in 2024 — the established benchmark
[18] Market Data Forecast (2024)
Global CLT market CAGR 2025–2033 — among the fastest in construction materials
[3] IMARC Group (2024)
North America CLT CAGR 2025–2034 — the fastest-growing regional market globally
[20] Expert Market Research (2024)
The US Army Corps of Engineers has mandated the evaluation of mass timber structural options during the design phase of all vertical construction projects,[20] signalling institutional-level adoption that is typically a leading indicator of broader market normalisation. The IBC 2021 now permits CLT in building Types IV-A, IV-B, and IV-C — up to 18 storeys.[8]
Specify mass timber
with confidence.
Explore Panel Haus CLT configurations — structural panels, insulation options, and hybrid SIP+CLT assemblies — for your next project.
[1] Younis, A. et al. (2023). Buildings, MDPI. Review of 27 LCA studies. ~40% average carbon reduction vs. traditional materials. · [2] Structurlam / Sustainable Lumber Co. (April 2024). sustainablelumberco.com. 1,394+ m² installable per day by 6 technicians. · [3] IMARC Group (2024). imarcgroup.com. CLT market USD 1.74B (2024) → USD 3.85B (2033), CAGR 9.2%. · [4] MarketsandMarkets (2024). marketsandmarkets.com. Adhesive-bonded CLT; ±0.2 mm CNC tolerances. · [5] Calderón, J. / ArchDaily (2025). archdaily.com. CLT: 400 kg/m³ vs. concrete: 2,700 kg/m³; same structural resistance. · [6] MarketDataForecast (2025). marketdataforecast.com. CNC precision ±0.2 mm for BIM-driven CLT construction. · [7] NC State University CNR (August 2022). cnr.ncsu.edu. UBC Brock Commons: 18 storeys in <70 days; 7-storey CLT survived 14 seismic simulations incl. Kobe-equivalent forces. · [8] International Building Code (IBC) 2021. Types IV-A, IV-B, IV-C — up to 18 storeys. iccsafe.org · [9] Younis, A. et al. (62-article LCA review). Cited in Hemmati et al. (2024), MDPI Buildings. 43% GHG avoided when RC substituted with mass timber. · [10] USDA Forest Service. usda.gov. Waugh Thistleton: 15% overall savings vs. conventional. · [11] Laguarda Mallo & Espinoza (2016). ResearchGate. CLT 21.7% more economical than steel/concrete for performing arts centre. · [12] Hemmati, M. et al. (June 2025). Sustainability, 17(12), 5602. MDPI. doi:10.3390/su17125602. 2,757 tonnes CO₂eq stored; 198 vs. 243 kg CO₂eq/m² (CLT vs. steel). · [13] Reanin Research (2024). reanin.com. 52% of eco-building projects incorporate CLT. · [14] UNEP / Global Alliance for Buildings (2022). 37% of global energy-related CO₂ from buildings. · [15] ScienceDirect (January 2024). Applied Energy. Mass timber GWP reduction: 39–51% vs. RC excl. biogenic carbon. · [16] Chen, X. et al. (cited in Hemmati 2024). Portland, OR CLT vs. RC: 69.5% lower embodied carbon incl. biogenic. · [17] MIT Climate Portal. climate.mit.edu. CLT carbon benefits contingent on sustainably managed forest supply chains. · [18] MarketDataForecast (2025). Europe: 45.3% global share. marketdataforecast.com · [19] Cazemier, D.S. (2017). UNSW Faculty of Built Environment. journalofindustrializedconstruction.com · [20] Expert Market Research (2024). expertmarketresearch.com. North America CAGR 29.6%; US Army Corps of Engineers mandated mass timber evaluation.