---
title: "Pressure-Treated Timber - GWP and renovation use"
canonical_url: https://fremtidenstegnestue.dk/en/knowledge/materials/trykimpraegneret-trae
markdown_url: https://fremtidenstegnestue.dk/en/knowledge/materials/trykimpraegneret-trae.md
author: "Fremtidens Tegnestue"
page_type: material
primary_intent: "Explain use, GWP and renovation relevance for Pressure-Treated Timber."
primary_keyword: "Pressure-Treated Timber"
audience: "Homeowners, studios and agents researching material choices."
summary: "Pressure-treated timber is structural timber treated with protective chemicals under pressure to resist rot, fungi, and insects. Used for decking, carports, fencing, and structures in moist environments. Modern preservatives (CCA-free) are far less toxic than older chromium-copper-arsenic (CCA) treatments."
source_basis:
  - "estimatee based on the EN 15804 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/trae
    relation: alternative-material
  -
    url: https://fremtidenstegnestue.dk/en/knowledge/materials/clt
    relation: alternative-material
  -
    url: https://fremtidenstegnestue.dk/en/knowledge/materials
    relation: hub
  -
    url: https://fremtidenstegnestue.dk/en/knowledge/concepts/lca
    relation: concept
status: published
---
# Pressure-Treated Timber - GWP and renovation use
Canonical URL: https://fremtidenstegnestue.dk/en/knowledge/materials/trykimpraegneret-trae
Markdown URL: https://fremtidenstegnestue.dk/en/knowledge/materials/trykimpraegneret-trae.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
Pressure-treated timber is structural timber treated with protective chemicals under pressure to resist rot, fungi, and insects. Used for decking, carports, fencing, and structures in moist environments. Modern preservatives (CCA-free) are far less toxic than older chromium-copper-arsenic (CCA) treatments.
## 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 | 0.5 kg CO₂-eq/kg |
| Density | 550 kg/m³ |
| Expected lifetime | 25–40 years (in outdoor use), 40–60 years (with minimal moisture exposure) |
## Use

- Decking and terraces
- Fences and picket fences
- Carports and sheds
- Structures in soil and water (piles, foundations)
## Renovation relevance
Pressure-treated timber is used in renovation for new decking, fences, and carports. Consider thermally modified wood or larch as alternatives that give a more natural appearance and are easier to dispose of.
## Comparison

| Material | GWP |
| --- | --- |
| Structural timber (untreated) | -0.72 |
| Thermally modified timber | -0.5 |
| Pressure-treated timber | 0.5 |
| Composite decking | 2.1 |
## FAQ
### Is pressure-treated timber safe?
Modern pressure treatment without CCA (typically copper-azole or copper-quat) is classified as safe for normal construction and decking use. Old CCA-treated materials should be handled with care and delivered to hazardous waste.
### Can pressure-treated timber be painted?
Yes, but the timber must be dry (typically 3–6 months after treatment). Use diffusion-open paint that allows the timber to breathe. Green freshly treated timber should not be painted immediately.
### Are there alternatives to pressure-treated timber for decking?
Yes — thermally modified wood, Siberian larch, African hardwood (teak, merbau), and composite decking boards are alternatives. Thermally modified wood and larch are most sustainable. Tropical timber requires FSC certification.
### Can pressure-treated timber be recycled?
Pressure-treated timber is hazardous waste and must NOT be burned in normal wood stoves or delivered as normal firewood. It must go to specialist chemical waste handling or is only suitable for landfill.
## Sources and basis
- estimatee based on the EN 15804 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
- [Structural Timber](https://fremtidenstegnestue.dk/en/knowledge/materials/trae): alternative-material
- [CLT (Cross-Laminated Timber)](https://fremtidenstegnestue.dk/en/knowledge/materials/clt): 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/trykimpraegneret-trae) 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.