Interstitial condensation typically occurs when warm, moist air from inside a building penetrates into the built fabric and meets a cold surface causing the air to cool, lowering its capacity to carry moisture, and resulting in condensation on the cold surface. This typically takes place in the refurbishment of existing buildings where insulation is applied to exterior walls, roof or floor construction.
In accordance with the EnerPHit standard you may need to have your construction details assessed for condensation prior to building certification. Please contact firstname.lastname@example.org for further information.
BRE use WUFI-2D to analyse and quantify heat and moisture through construction materials which also assess water penetration into walls/roof from the exterior surface due to rain and wind as sometimes it can lead to significant water accumulation in the construction.
The vapor transport mechanisms included in WUFI are:
The liquid transport mechanisms taken into account are:
Fiqure 1: Typical WUFI output