moisture source for building envelope

See: Moisture from indoor

Moisture found in building envelope could originate from indoor, outdoor or from the materials and construction. The main indoor moisture sources for residential buildings are the occupants and their activities. Outdoor moisture sources are the precipitation and the humidity in the air. The initial moisture content of the building materials, water stored during construction, and accidental water entrances (such as flood) are also important sources.

Rising damp is a common problem in older buildings. Moisture rises up the wall by capillary action depositing salts and damaging the wall finishes. However Rising Damp is less common than commonly thought and dampness at the base of a wall may be due to other damp problems such as Penetrating Damp and Condensation."-- EBS

Excerpt of "Wall moisture problems in Alberta dwellings " by Robert W Tom (at Online source:)

Exterior Moisture: Exterior moisture, most often from direct rain penetration, was a contributing factor in 91% of problems. Most problems occurred at window and door perimeters and decks .

Interior Moisture: Condensation moisture, caused by occupants trying to maintain indoor humidity above 30% during the winter, contributed to 14% of all problems.

"Excessive moisture in buildings can result from a number of causes: (at WBDG)

• Rainwater leaks through roofs and walls;,
• Groundwater intrusion into basements and crawl spaces through walls and floors;,
• Leaking or burst water pipes;,
• Indoor moisture sources;,
• Construction moisture; and,
• Condensation of moist air.,

Also see

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A comparison of airborne ergosterol, glucan and Air-O-Cell data in relation to physical assessments of mold damage and some other parameters, by Foto, M., Vrijmoed, L. L. P., Miller, J. D., Ruest, K., Lawton, M. and Dales, R. E., 2005

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Dampness in buildings, 2nd ED, by Douglas, J. and Stirling, J. S., 1997

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ICC performance code for buildings and facilities, by ICC, 2000

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Look to interior for source of moisture that causes rot , by Gustavson, M., 2000

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Microfungal contamination of damp buildings - examples of risk constructions and risk materials, by Gravesen, S., Nielsen, P.A., Iversen, R., Nielsen, K.F, 1999

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Pioneering Building Envelope Commissioning to Prevent Moisture Intrusion, by Scott, R., Aia, N. and Macphaul, D., 2005

flood

Steady-state moisture diffusion in curved walls, in the absence of condensate flow, via the BEM: a practical Civil Engineering approach (Glaser method) , by Tadeu, A., Sim?es, N. and Branco, F., 2003

construction moisture

The appearance of moulds in buildings, by Gornes, J. A., 1995

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Two-dimensional transient heat and moisture simulations of rising damp with WUFI 2D, by Holm, A. and K¨ąnzel, H.M, 2000

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Uncertainty of hygrothermal calculations, by Holm, A.H. and H.M. K¨ąnzel, 2002

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Wall moisture problems in Alberta dwellings, by Building Envelope Engineering Inc, 2000