--- title: "CLT (Cross-Laminated Timber) - GWP and renovation use" canonical_url: https://fremtidenstegnestue.dk/en/knowledge/materials/clt markdown_url: https://fremtidenstegnestue.dk/en/knowledge/materials/clt.md author: "Fremtidens Tegnestue" page_type: material primary_intent: "Explain use, GWP and renovation relevance for CLT (Cross-Laminated Timber)." primary_keyword: "CLT (Cross-Laminated Timber)" audience: "Homeowners, studios and agents researching material choices." summary: "CLT is solid wood panels built from crosswise layers of structural timber. It combines timber's carbon sequestration with high load-bearing capacity and dimensional stability. CLT is used as a direct replacement for concrete in floors, walls and roof structures — with significantly lower climate impact." source_basis: - "ECO Platform EPD average" - "Social- og Boligstyrelsen: Klimakrav og LCA i bygningsreglementet: https://www.sbst.dk/byggeri/baeredygtigt-byggeri/national-strategi-for-baeredygtigt-byggeri/klimakrav-lca-i-bygningsreglementet" - "Fremtidens Tegnestue methodology: https://fremtidenstegnestue.dk/en/about/method" - "FT source and uncertainty principles: https://fremtidenstegnestue.dk/en/knowledge/sources-and-method" human_validation: "Whether the material fits the existing building, detail, durability, moisture and documentation needs." responsibility_line: "AI can prepare, compile and flag uncertainty. The architect validates the consequences." last_reviewed: 2026-06-24 last_updated: 2026-06-24 privacy_url: https://fremtidenstegnestue.dk/en/privacy related_pages: - url: https://fremtidenstegnestue.dk/en/knowledge/materials/beton relation: alternative-material - url: https://fremtidenstegnestue.dk/en/knowledge/materials/trae relation: alternative-material - url: https://fremtidenstegnestue.dk/en/knowledge/materials/staal relation: alternative-material - url: https://fremtidenstegnestue.dk/en/knowledge/materials relation: hub - url: https://fremtidenstegnestue.dk/en/knowledge/concepts/lca relation: concept status: published --- # CLT (Cross-Laminated Timber) - GWP and renovation use Canonical URL: https://fremtidenstegnestue.dk/en/knowledge/materials/clt Markdown URL: https://fremtidenstegnestue.dk/en/knowledge/materials/clt.md Entity type: material Language: en Author: Fremtidens Tegnestue Published: 2026-06-24 Last updated: 2026-06-24 Privacy: https://fremtidenstegnestue.dk/en/privacy ## Short answer CLT is solid wood panels built from crosswise layers of structural timber. It combines timber's carbon sequestration with high load-bearing capacity and dimensional stability. CLT is used as a direct replacement for concrete in floors, walls and roof structures — with significantly lower climate impact. ## Who it is relevant for Homeowners, studios and agents researching material choices. ## What FT can prepare - Summarise material properties, GWP, common uses, renovation relevance and alternatives. ## What the architect validates - Whether the material fits the existing building, detail, durability, moisture and documentation needs. ## Key figures | Metric | Value | | --- | --- | | GWP | -0.55 kg CO₂-eq/kg | | Density | 500 kg/m³ | | Expected lifetime | 100+ years | ## Use - Floor slabs - Load-bearing walls - Roof structures - Facade elements - Stairs ## Renovation relevance CLT is used for extensions and adding extra storeys to existing buildings — precisely because it is lightweight. A lightweight top storey in CLT places much lower demands on existing foundations and structures than a concrete supplement. ## Comparison | Material | GWP | | --- | --- | | CLT | -0.55 | | Structural timber | -0.72 | | Concrete | 0.13 | | Steel | 1.46 | ## FAQ ### Is CLT strong enough for residential buildings? Yes. CLT is approved for load-bearing structures up to many storeys. In Scandinavia, CLT buildings up to 18 storeys have been built. It has good fire resistance (charring protects the core) and high dimensional stability. ### What does CLT cost compared to concrete? CLT is typically 15–25% more expensive in material cost than concrete, but easier to install, faster to build, and gives lower total costs including foundation (lighter structure = lighter foundation). ### Does CLT work in the Danish climate? Yes, CLT is well-suited to the Northern European climate. Correctly built with vapour barrier and ventilated facade cladding, it performs well. It should be protected from direct moisture exposure. ### Does CLT store CO₂ permanently? CO₂ is stored as long as the building stands. If CLT elements are dismantled and reused in new structures, storage continues. CO₂ is only released again upon burning or decomposition. ## Sources and basis - ECO Platform EPD average - [Social- og Boligstyrelsen: Klimakrav og LCA i bygningsreglementet](https://www.sbst.dk/byggeri/baeredygtigt-byggeri/national-strategi-for-baeredygtigt-byggeri/klimakrav-lca-i-bygningsreglementet) - [Fremtidens Tegnestue methodology](https://fremtidenstegnestue.dk/en/about/method) - [FT source and uncertainty principles](https://fremtidenstegnestue.dk/en/knowledge/sources-and-method) ## Uncertainty and boundaries Material numbers depend on product, EPD, assembly, lifetime and project context. ## Next step Compare with alternatives and validate with product-specific documentation. ## Related pages - [Concrete](https://fremtidenstegnestue.dk/en/knowledge/materials/beton): alternative-material - [Structural Timber](https://fremtidenstegnestue.dk/en/knowledge/materials/trae): alternative-material - [Structural Steel](https://fremtidenstegnestue.dk/en/knowledge/materials/staal): alternative-material - [Materials](https://fremtidenstegnestue.dk/en/knowledge/materials): hub - [LCA](https://fremtidenstegnestue.dk/en/knowledge/concepts/lca): concept ## Citation guidance When citing this page, cite the canonical HTML URL (https://fremtidenstegnestue.dk/en/knowledge/materials/clt) as the public source and use this Markdown URL only as the agent-readable representation. Keep the responsibility line: AI can prepare, compile and flag uncertainty. The architect validates the consequences.