Vapour Barrier.
The vapour barrier has a small CO₂ footprint relative to the overall building structure, but its correct installation is crucial for the building's long-term climate performance.
- Carbon Footprint (GWP)
- 2 kg CO₂-eq/kg
- Density
- 0,1–0,5 kg/m² (afhænger af tykkelse)
- Expected Lifespan
- 50+ år (i beskyttet position)
Source: estimat baseret på EN 15804 gennemsnit
What is vapour barrier?
A vapour barrier is a tight plastic film that prevents moisture diffusion into insulation and structure. It is crucial for avoiding mould and structural damage in insulated buildings. Correctly installed vapour barrier with tight joints and penetrations is the foundation of sound building physics.
Carbon Footprint Compared
Negative carbon footprint (green) indicates carbon storage. Data based on EPD averages from ECO Platform and estimates per EN 15804.
Typical Applications
- check_circle Roof and ceiling (interior side of insulation)
- check_circle Exterior wall (interior side in lightweight construction)
- check_circle Floor against soil (under ground slab)
- check_circle Crawl spaces
In Renovation
The vapour barrier is the most underrated element in energy renovation. A leaking vapour barrier can destroy even the best insulated structure. Always prioritise airtightness during installation.
Questions about vapour barrier
Is a vapour barrier the same as a windproof membrane?
No. The vapour barrier is on the warm side (interior) of insulation and is tight (sd-value > 50 m). The windproof membrane is on the cold side (exterior) and is diffusion-open but windtight (sd < 0.5 m).
What happens if the vapour barrier has holes?
Moisture from the indoor climate penetrates the insulation and condenses on cold surfaces. This causes moisture accumulation, mould, and possible rot in timber structures. Airtightness is paramount.
Can the vapour barrier be perforated by electrical installations?
Yes — all penetrations (pipes, electrical cables, ventilation ducts) require careful sealing with vapour barrier sleeves. Place electrical conduits and pipes on the warm side of the vapour barrier.
Are there alternatives to plastic vapour barriers?
Yes — intelligent vapour barriers (variable sd-value) can open in summer and close in winter, giving better drying potential and reducing mould risk. They are more expensive but more fault-tolerant.
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