---
title: "Radon Membrane - GWP and renovation use"
canonical_url: https://fremtidenstegnestue.dk/en/knowledge/materials/radon-membran
markdown_url: https://fremtidenstegnestue.dk/en/knowledge/materials/radon-membran.md
author: "Fremtidens Tegnestue"
page_type: material
primary_intent: "Explain use, GWP and renovation relevance for Radon Membrane."
primary_keyword: "Radon Membrane"
audience: "Homeowners, studios and agents researching material choices."
summary: "The radon membrane is a thick, diffusion-tight plastic film placed under the ground slab to prevent radon gas from penetrating from the subsoil. Radon is a natural radioactive gas formed by the decay of radium in soil and bedrock. It is the second-largest cause of lung cancer in Denmark after smoking."
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/dampspaerre
    relation: alternative-material
  -
    url: https://fremtidenstegnestue.dk/en/knowledge/materials
    relation: hub
  -
    url: https://fremtidenstegnestue.dk/en/knowledge/concepts/lca
    relation: concept
status: published
---
# Radon Membrane - GWP and renovation use
Canonical URL: https://fremtidenstegnestue.dk/en/knowledge/materials/radon-membran
Markdown URL: https://fremtidenstegnestue.dk/en/knowledge/materials/radon-membran.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
The radon membrane is a thick, diffusion-tight plastic film placed under the ground slab to prevent radon gas from penetrating from the subsoil. Radon is a natural radioactive gas formed by the decay of radium in soil and bedrock. It is the second-largest cause of lung cancer in Denmark after smoking.
## 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 | 2.2 kg CO₂-eq/kg |
| Density | 0.5–1.5 kg/m² (depends on thickness) |
| Expected lifetime | 100+ years (in a protected position beneath concrete) |
## Use

- Under ground slabs in new homes
- Renovation of existing ground slabs
- Basements and crawl spaces
- Radon-exposed areas in Denmark
## Renovation relevance
Radon membrane can be installed under new floor coverings when renovating ground floors. In existing houses without radon membrane, however, the most effective solution is mechanical radon suction below the concrete slab.
## Comparison

| Material | GWP |
| --- | --- |
| Vapour barrier (PE) | 2 |
| Radon membrane | 2.2 |
| PVC pipes | 2.41 |
| Roofing membrane | 2.5 |
## FAQ
### Is radon a problem in all parts of Denmark?
Radon is a particular problem on Bornholm (granite) and certain Jutland areas with uranium-bearing soil. Check the radon map on the GEUS website to see if your plot is in a risk zone.
### When is a radon membrane mandatory?
BR18 requires radon measures in all new homes in Denmark. In high-risk areas, requirements are tightened. It is always recommended to carry out a radon measurement before construction begins.
### Can radon problems be solved in existing houses?
Yes — ventilation systems with under-pressure (radon sump) under the concrete floor are the most effective solution. Alternatively, you can improve ventilation of crawl spaces and seal cracks and penetrations.
### What is the acceptable radon concentration?
WHO recommends below 100 Bq/m³. BR18 requires below 100 Bq/m³ in new homes. The EU radiation protection directive sets 300 Bq/m³ as a reference level for existing homes.
## 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
- [Vapour Barrier](https://fremtidenstegnestue.dk/en/knowledge/materials/dampspaerre): 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/radon-membran) 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.