Four Point Inspector
Four Point Inspector

Moisture Intrusion Inspection

Here are a few key highlights of what can be going on in and around your home

How does moisture get into the house?

Moisture or water vapor moves into a house in ways of air infiltration. Air movement accounts for more than 98% of all water vapor movement in building cavities. Air naturally moves from high-pressure areas to lower ones by the easiest path possible, such as a hole or crack in the building envelope.

Moisture transfer by air currents is very fast (in the range of several hundred cubic feet of air per minute). Replacement air will infiltrate through the building envelope unless unintended air paths are carefully and permanently sealed by diffusion through building material. Most building materials are slow moisture diffusion and to large of a degree to handle, although they never stop it completely from leaks that come from the roof, plumbing leaks and flooding which can be caused by seepage from runoff or rising groundwater can be catastrophic. 

Climate Zones

In the northern U.S., moisture vapor problems are driven primarily by high indoor relative humidity levels, combined with low outdoor temperatures during the winter. In the southern U.S. (especially the southeast), the problem is largely driven by high outdoor humidity and low indoor temperatures during summer months. Mixed climates are exposed to both conditions and can experience both types of problems. Humid climates, in general, will be more of a problem than dry climates. Wind-driven rain is the main cause of leaks through the building envelope.


A roof leak may lead to the growth of visible mold colonies in the attic that can grow unnoticed. Roof penetrations increase the likelihood of water leaks due to failed gaskets, sealants and flashing. The number of roof penetrations may be reduced by a variety of technologies and strategies, including consolidation of vent stacks below the roof, making sure the exhaust fan caps routed through walls instead of the roof high-efficiency combustion appliances, which can be sidewall-vented electrically powered HVAC equipment and hot water heaters that do not require flue. Oftentimes, inspectors discover missing, incorrectly installed or corroded flashing pipes.


Distribution pipes and plumbing fixtures can be the source of large amounts of moisture intrusion. If the floor is moist and/or discolored, then moisture damage is already in progress. Most plumbing is hidden in the walls, so serious problems can begin unnoticed.

One of the most important means of moisture management in the bathroom is the exhaust fan. A non-functioning exhaust fan overloads the bathroom with damp air. The fan should vent into the exterior, not into the attic.

Utility Room

In the water heater tank should be clean and rust-free, the area around the water softener tank should be clean and dry. Make sure that all through-the-wall penetrations for fuel lines, ducts, and electrical systems of heating system are well-sealed and all ducts should be clean and dust-free. Inspect the air supply registers in the house for dust accumulation, filters, supply lines, exterior wall penetrations, vents, ductwork and drainage of the cooling system must all be in good working order to avoid moisture problems in order to prevent any other types damages to your home.


Identifying areas for stains or discolorations at all roof penetrations, chimneys, plumbing vents and skylight wells are common places where moisture may pass through the roof. Any such locations must be inspected for wetness, a musty smell and/or visible signs of mold.

Are there areas of the insulation that appear unusually thin? Rust or corrosion around recessed lights are signs of a potential electrical hazard.


Moisture can enter a building in a number of different ways. High levels of moisture can cause building defects and health ailments.  Some common moisture-related problems include, structural wood decay, high indoor humidity resulting condensation, expansive soil, which may crack the foundation through changes in volume, or softened soil, which may lose its ability to support an overlying structure, undermined foundations, metal corrosion, ice dams and mold growth. 
Mold can only grow in the presence of high levels of moisture. People who suffer from the following conditions can be seriously (even fatally) harmed if exposed to elevated levels of airborne mold spores; Asthma, Allergies, Lung Disease, and/or compromised immune systems 


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