Excessive Moisture in Buildings


Many owners of single family homes and other buildings are reporting problems with excess moisture, condensation and even frost in buildings and attic spaces. These problems are worse during changing seasons when heating and air conditioning units, which naturally draw moisture out of the air, are not being used. These problems are not related to the roofing but, just the same, are resulting in the rot and decay of structural lumber.


The root cause of this problem is that, with energy efficiency measures we have taken to make buildings “tighter,” we have sealed them off so that moisture cannot escape from them. Oftentimes, these problems seem to occur after an older building has been remodeled with new doors, windows, and siding. The moisture that is generated in a home from cooking, washing, showers, and even house plants cannot escape the structure and will condense on any cool surface it reaches. These cool surfaces are usually window glass and the underside of the roof decking.


This problem is from moisture which is generated inside the building. Because it often manifests itself with condensation or frost in the attic, property owners automatically assume it is a roof-related issue. Pro-active roofing contractors learn how to recognize when these problems might occur and prevent them by ensuring their jobs have adequate ventilation.


Ensuring that all areas beneath the roof deck have proper ventilation will prevent call-backs for the roofing contractor. This is easily done with conventional attic spaces but becomes more complex with cathedral ceilings and structural insulated panels. While steps can be taken to limit moisture inside the structure and to prevent its transfer into the space beneath the roof deck, those are not adequate solutions to this complex problem. The only solution is the creation of positive ventilation and airflow to maintain temperature consistency between the vented area and the outside. This allows moisture to escape rather than condense. Additional assistance can be obtained from Classic Products, Inc. or from ventilation experts.