Interstitial Condensation In Roof

Inside the roof wall or floor elements.

Interstitial condensation in roof. Interstitial condensation is condensation which occurs between layers of the construction i e. Only through fasteners such as screws brick ties and roof screws would be at risk in such high rh environments. The incorporation of adequate insulation and ventilation in the roof void of a cold roof construction or sufficient insulation and vapour control layer in a warm roof construction will prevent the formation of interstitial condensation in the normal range of environmental conditions experienced. The moisture laden air can penetrate into hidden interstitial wall cavity through the exterior in a warm humid outdoor period and from inside the building during.

Condensation risk analysis for the glasgow school with the dew point indicated under the membrane. In addition to providing a psychometric chart this article includes dew point calculation formulas and references to dew point and psychometric chart calculations research and psychometric chart preparation or interpretation. How to find the dew point in buildings when does moisture condense on surfaces and in cavities. Interstitial condensation is different from surface condensation such as that caused by cold bridging and its occurrence within the roof or wall structure of a building is difficult to detect without investigation.

The standard of roof ventilation varies widely but the current building regulations specify that 270mm mineral wool should be used to insulate your a roof space at a minimum. The dew point defines when moisture will begin to condense on building. Interstitial condensation can create structural dampening that occurs when moist air penetrates inside the hidden space within an enclosed wall roof or floor cavity structure. It is the result of the interaction between a complex set of factors.

Interstitial condensation can occur in solid and cavity wall properties and happens when pressure and temperature differences force warm humid air through hygroscopic water absorbing materials until they reach a point cold enough for it to condense upon a surface. When that moisture laden air reaches a layer inside the interstitial structure that is at dew point temperature it condenses into liquid water on that surface. Condensation in a cold roof. Interstitial condensation can cause deterioration or even failure of the components of the assembly potentially shortening their useful lifespan.

Swimming pools may have dew points exceeding 60 f 15 c and hence would require more r value on the exterior to avoid interstitial condensation in cold climates. Moisture will condense in this zone to form interstitial condensation. Interstitial condensation is a form of structural damp that occurs when warm moist air penetrates inside a wall roof or floor structure.