CLT CL24h
Grade · default condition
ASTM ANSI/APA PRG 320 · EN 16351
CL24h = spruce CLT, homogeneous C24 lamellas
European default: PEFC/FSC spruce-fir lamellas graded C24, PUR-bonded, for floors, walls and roofs.
Values for the CL24h condition
Other CLT tempers and conditions
CLT is listed in 5 conditions; see the grade overview at CLT.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
PRG 320 Grade E1 | North American stock layup: machine-stress-rated Spruce-Pine-Fir, widest availability from US/Canadian plants. | — | 15 | 0.8 | — | 0.12 W/m·K |
PRG 320 Grade V2 | Choose where higher density, better rolling shear and screw/connector capacity are needed (heavy floors, connections). | — | 15 | 0.9 | — | 0.13 W/m·K |
CL24hDefaultThis page Spruce CLT, homogeneous C24 lamellas | European default: PEFC/FSC spruce-fir lamellas graded C24, PUR-bonded, for floors, walls and roofs. | — | 16 | 0.9 | — | 0.12 W/m·K |
Spruce CLT, homogeneous C30/C32 lamellas | Pick when spans or wall loads govern and machine-graded high-stiffness lamellas justify the price premium. | — | 20 | 0.9 | — | 0.12 W/m·K |
Hardwood CLT | Specialty high-capacity panels for slender slabs, exposed architectural use or heavy point loads; costlier and heavier. | — | 25 | 1.1 | — | 0.17 W/m·K |
What is CLT CL24h?
CLT CL24h is CLT in the CL24h grade — european default: PEFC/FSC spruce-fir lamellas graded C24, PUR-bonded, for floors, walls and roofs. CLT CL24h has a tensile strength of 16 MPa (2.32 ksi), weaker than 61% of natural material grades. Elongation at break is 0.9% and the elastic modulus is 11 GPa (1.6 Msi). CLT CL24h has a density of 0.47 g/cm³ (0.017 lb/in³), lighter than 80% of natural material grades.
Advantages
- Easy to machine — 92/100, better than 97% of natural material grades
- Lightweight — 0.47 g/cm³ (0.017 lb/in³), better than 80% of natural material grades
Limitations
- Limited service temperature — 55°C (131 °F), worse than 96% of natural material grades
- Low fracture toughness — 0.4 MPa·√m (0.364 ksi·√in), worse than 86% of natural material grades
CLT CL24h properties
Typical room-temperature values for CLT CL24h; 13 are specific to this condition. Other listed values are CLT reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
CLT CL24h has a density of 0.47 g/cm³ (0.017 lb/in³), lighter than 80% of natural material grades.
Mechanical9
CLT CL24h has a tensile strength of 16 MPa (2.32 ksi), weaker than 61% of natural material grades. Elongation at break is 0.9% and the elastic modulus is 11 GPa (1.6 Msi).
Thermal5
CLT CL24h is rated for continuous service to 55°C (131 °F). It conducts heat at 0.12 W/m·K (0.0693 BTU/hr·ft·°F), worse than 70% of natural material grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical2
CLT CL24h is an electrical insulator with a dielectric strength of 4 kV/mm (101.6 V/mil) and a resistivity of 1×10⁸ Ω·m.
Chemical & Environmental1
Corrosion resistance is fair (45/100), better than 53% of natural material grades.
Sustainability3
Producing a kilogram of CLT CL24h takes about 9 MJ of energy and emits 0.42 kg of CO₂ — less than 65% of natural material grades. Typical recycled content is 2%.
Manufacturability2
CLT CL24h's machinability is excellent (92/100, better than 97% of natural material grades).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CLT CL24h
Is CLT easy to machine?
CNC-routed and drilled easily with carbide spiral tooling and strong dust extraction; openings, service chases and connector pockets are cut in the plant to ±1–2 mm.
Can CLT be welded?
Not weldable — panels are joined by self-tapping screws, splines/half-lap panel joints, glued-in rods and steel brackets.
Can CLT be formed, bent or molded?
Formed only during production by cold-pressing crossed lamella layers (0.6–1.0 MPa, PUR); curved panels need pre-bent lamellas, no post-forming.
What surface finishes work on CLT?
Sand/plane for visual-quality faces, then UV/water-based clear coat, stain or fire-retardant coating; end grain and exposed faces must be sealed against moisture and detailed for service class 1–2.
CLT chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| cellulosesoftwood lamella, oven-dry basis | 40 – 45 | 42 |
| hemicellulose | 24 – 30 | 27 |
| lignin | 25 – 31 | 28 |
| extractives + ashresins, terpenes, minerals | 1 – 4 | 2.5 |
| structural adhesive (PUR or MUF)EN 15425 / EN 301 bond lines | 0.3 – 1.5 | 0.6 |
| moisture (as delivered)12 ± 3 % MC per EN 16351 | 9 – 15 | 12 |
CLT CL24h — frequently asked
What is CLT CL24h used for?
CLT CL24h is typically used for mass timber walls/floors, multi-story buildings, prefabricated modules, roof panels and bridges. In short: two-way mass-timber plate; highest panel machinability rating; prefabricated to millimetre tolerance.
What is the tensile strength of CLT CL24h?
CLT CL24h has a typical tensile strength of 16 MPa (2.32 ksi) — weaker than 61% of natural material grades. Strength varies by condition: see the 5 listed tempers.
Is CLT CL24h easy to machine?
Yes — machinability is rated excellent (92/100, better than 97% of natural material grades). CNC-routed and drilled easily with carbide spiral tooling and strong dust extraction; openings, service chases and connector pockets are cut in the plant to ±1–2 mm.
Can CLT CL24h be welded?
Not weldable — panels are joined by self-tapping screws, splines/half-lap panel joints, glued-in rods and steel brackets.
What surface finishes work on CLT CL24h?
Sand/plane for visual-quality faces, then UV/water-based clear coat, stain or fire-retardant coating; end grain and exposed faces must be sealed against moisture and detailed for service class 1–2.
Can CLT CL24h be formed, bent or molded?
Formed only during production by cold-pressing crossed lamella layers (0.6–1.0 MPa, PUR); curved panels need pre-bent lamellas, no post-forming.
What is the maximum service temperature of CLT CL24h?
CLT CL24h is rated for continuous use to about 55°C (131 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 16351 Timber structures — Cross laminated timber — Requirements — CEN (2021)
- ANSI/APA PRG 320 Standard for Performance-Rated Cross-Laminated Timber — APA – The Engineered Wood Association (2019)
- EN 338 Structural timber — Strength classes — CEN (2016)
- Wood Handbook — Wood as an Engineering Material (FPL-GTR-190) — USDA Forest Products Laboratory (2010)
- CLT Handbook (US Edition) — FPInnovations / Binational Softwood Lumber Council (2013)
- CLT panel technical data / ETA declarations (KLH, Stora Enso, Binderholz) — producers (2023)
- Inventory of Carbon & Energy (ICE) v3 — cross laminated timber — Circular Ecology (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.