J&P; Home and Environmental Inspections LLC
/2.jpg  
J&P; Home and Environmental Inspections LLC



John Prohaska
P.O.Box 36143
Des Moines, IA. 50320
United States
515-240-5672

 






Attention Remediators

J&P; Inspections is qualified
to perform Mold Clearance
on foreclosed homes across
the state of Iowa. Call us
today for more information.

 



BBB


Mold inspection payment



    Causes of Mold

    Mold and mildew issues are generally related to three conditions; 1) the indoor temperature and humidity, 2) the climate, and 3) the type of construction details used in assembly of the building envelope. The table below correlates the type of problem with the main cause identified. For example, mold and mildew on inside surfaces occur where high relative humidity levels are found indoors, and the prevailing climate includes cold weather or driving rain coupled with little sunshine. The cause may also have been the construction details used; that is, there may have been a thermal short-circuit or a thermal bridge or insufficient insulation in the region of the mold and mildew problem.

    Considering the indoor conditions associated with all of these different problems, high indoor relative humidity is present in all cases and the interior air pressure of the house at the ceiling level was often higher than the outside (80% of the houses that reported problems were electrically heated and did not have active flues). Poor airtightness can also be associated with most of the problems reported.

    The indoor conditions and the climate continually stress the house envelope. This stress is aggravated further if the region lacks a good drying season. Keeping this in mind, we can improve the performance of houses, with regards to moisture damage, by controlling some of the moisture sources, ventilating, and improving the design and construction of the building envelope.

    Reduction of the amount of moisture generated will lower the level of humidity within the unit. The less moisture generated, the less there is to condense or to migrate into cavities.

    Ventilation can remove the moisture that has been generated and create a favorable (negative) pressure difference across the outside walls and ceiling.

      CAUSES
     
    PROBLEMS INDOOR CONDITIONS CLIMATE CONSTRUCTION

    Mold and mildew on inside surfaces of exterior walls
    • High relative humidity levels
    • Cold weather
    • Driving rain/little sunshine
    • Cold interior wall surfaces due to missing insulation or thermal short circuits

    Window condensation
    • High relative humidity levels
    • Cold Weather
    • Thermal resistance of glazing too low

    Basement and crawlspace condensation
    • High relative humidity levels
    • Cold weather
    • High water table
    • Rain
    • Poor drainage
    • Faulty air barrier
    • Faulty vapour barrier
    • Improper flashings
    • Cracked foundation
    • Blocked drain tile

    Attic condensation
    • High relative humidity levels
    • Pressurized interior
    • Mild weather/high outside relative humidity /little sunshine
      OR
    • Very cold climate
    • Poor attic ventilation
    • Faulty air barrier
    • Faulty vapour barrier
    • Increased insulation

    Moisture in wall cavities
    • High relative humidity levels
    • Pressurized interior
    • Cold weather
      OR
    • Driving rain/little sunshine
    • Faulty air barrier
    • Faulty vapour barrier

    Siding damage
    • High relative humidity levels
    • Pressurized interior
    • Cold weather during spring
    • Driving rain/little sunshine
    • Faulty air barrier
    • Faulty vapour barrier
      AND/OR
    • Faulty rain screen

    This article was excerpted with permission from the technical documentation produced for Building Science Insight '83, "Humidity, Condensation and Ventilation in Houses", a series of seminars presented in major cities across Canada in 1983. All rights reserved.
















Moisture causes mold & mildew. Mold testing pinpoints the cause
of mold issues in your home.

/17.jpg







Infrared technology helps to identify moisture and structural
issues in your home.

/10.jpg










Home Inspection Web Site design and hosting by Grassfrog Technologies, LLC. Copyright © 2008-09, all rights reserved.