Why you should be concerned about moisture in your home

Moisture infiltration, especially hidden moisture is the most common cause of building defects ,damage and health ailments for the building's occupants. Moisture has multiple paths to enter the home and in the worst cases can make a home uninhabitable in fairly short order. Skilled and experienced home inspectors need a strong understanding of how moisture may enter a building, and where problem areas commonly occur.

Some of the frequently seen and common moisture-related issues include:

• Structural wood damage and decay
• Elevated indoor humidity (above 50%) with increased condensation on cool surfaces
• Expansive soil, which damages and cracks the foundation through changes in volume, or softened soil, which typically loses the ability to support the building
• Undermined foundations, especially dry laid rock foundations which are highly vulnerable and eventually collapse
• Metal rust and corrosion
• Roof ice dams which lead to roof leaks during the winter
• 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 and other breathing conditions
  • Allergic reactions
  • Lung diseases
  • Compromised immune systems
  • Cold and flu like symptoms that never improve

Note: Sensitivity to mold varies by individual. But even folks who do not suffer from these ailments may still be harmed by elevated levels of airborne mold spores. And mold will damage a structure even if the occupants aren't displaying sysmptoms. Living in a moldy home is never a good idea.

How moisture commonly enters a house

Moisture or water vapor can enter a house in multiple ways:

• 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 path offering the least resistance, like a hole or crack in the building envelope. Moisture movement by air currents is fast (around several hundred cubic feet of air every minute). Replacement air will infiltrate through the building envelope unless unintended air paths are carefully and permanently sealed
• Moisture diffusion through building materials (wood, drywall, concrete, etc) is a slow but unstoppable process. Many building materials slow moisture diffusion but never stop it completely
• Roof leaks from poor installation and/or worn out roof materials
• Plumbing leaks in supply and drain lines
• Flooding from runoff seepage or rising groundwater. This can be regularly seasonal or catastrophic
• Normal living activities like bathing, cooking, dishwashing and clothes washing. Indoor plants may also be a significant source of high levels of humidity

Effects of Climate Zones on Moisture Infiltration

In northern climes the moisture vapor problems are driven mostly by high indoor relative humidity levels in combination with low outdoor temperatures in the winter. Moisture laden inside air comes in contact with cold exterior air and building materials which causes an extreme amount of condensed water, often inside building cavities.

Compared to southern climes (especially the southeast), where the problem is the reverse with high outdoor humidity and low indoor temperatures (from air conditioning) during summer months. The same process of condensation on cooled surfaces and inside building cavities can create a major water damage problem.

The middle areas with mixed climates can be the worst situation since they are exposed to both conditions. Humid climates, in general, will be more of a problem than dry climates. Wind-driven rain (especially where siding is not being well maintained) is the main cause of leaks through the building envelope.

Home inspectors should check for moisture intrusion in the following areas

Roofs

A roof leak will set up conditions that can destroy a home. A leaking roof can help the growth of hidden mold colonies in the attic and walls. Roof penetrations are the weak points that increase the likelihood of water leaks due to failed gaskets, sealants and flashing. Reducing the number of roof penetrations by a variety of technologies and strategies will improve the integrity of the roof. Reduction techniques include:

• Consolidation vent stacks below the roof so only 1 penetration through the roof is needed
• Exhaust fans routed through the exterior walls instead of the roof
• Use high-efficiency combustion appliances, which can be sidewall-vented
• Electrically powered HVAC equipment and hot water heaters that do not generate combustion products that require a flue
• Adequate flashing to prevent water entrance at walls, chimneys and other vulnerable places.

Plumbing

• Since most plumbing is hidden in the walls this lets serious problems develop unnoticed. Water pipes and plumbing fixtures , with even a small leak over time, can be the source of large amounts of moisture intrusion and damage. If the wall is moist and/or discolored, then moisture damage is already happening
• 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. If the exhaust fan doesn’t turn on automatically when the bathroom is in use, consider recommending switching the wiring or switch. The lack of an exhaust fan should be called out in the inspection report. The fan should vent into the exterior, not into the attic.
• The bathroom sink, in particular, is a common source of moisture intrusion and damage. Although overflow drains can prevent the spillage of water onto the floor, they can become corroded and allow water to enter the cabinet.
• Use a moisture meter to check for elevated moisture levels in the sub-floor around the toilet and tub.
• Bathroom windows need to perform properly in a wide range of humidity and temperature conditions. Check to see if there are any obvious breaks in the weatherstripping and seals. Are there are stains or flaking on the painted surfaces?
• Check showers and bathtubs. Is the caulking is cracked, stiff or loose in spots? Are there cracked tiles or missing grout that may channel water to vulnerable areas? If some water remains in the bathtub after draining, it may be a warning sign of possible structural weakening and settlement in the floor beneath the tub.

Utility Room

• The water heater tank should be clean and rust-free
• The area around the water softener tank should be clean and dry
• Check that all through-the-wall penetrations for fuel lines, ducts, and electrical systems of heating system are well-sealed. 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

Attic

• Smell the air when you first enter the attic. If it smells damp or musty then it's lkikely that moisture is entering the attic through the roof or other sources
• Look 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 or discolored?
• Rust or corrosion around recessed lights are signs of a potential electrical hazard

Creating a dry basement

Building codes typically require damp-proofing of foundation walls. Which many folks will think of as all that's needed for a dry basement. But damp-proofing is not the same as water proofing which is extremely difficult to accomplish in most situations. Even a properly damp-proofed foundation still needs correct drainage both at and below grade to guide water away from the foundation.

• bituminous coating
• 3 pounds per square yard of acrylic modified cement
• 1/8-inch coat of surface-bonding cement
• or

In summary, moisture can enter a building in a number of different ways. High levels of moisture can cause building defects and health ailments.

Call 800-573-3170 Now to schedule your inspection