W07: Moisture Management

(3 points)

INTENT

Limit the potential for bacteria and mold growth within buildings from water infiltration and condensation.

SUMMARY

This WELL feature requires projects to implement techniques to minimize the presence of unintentional water and, when unavoidable, to manage it through material selection.

ISSUE

Excess moisture and dampness is a common problem in buildings, affecting about 20% of buildings in Europe, Canada and the U.S. It creates conditions conducive to the growth of mold and other biological pests, which can increase the risk of developing respiratory infections and asthma for those within the building. It is estimated that one fifth of asthma cases in the U.S. are caused by excess moisture and dampness in buildings, contributing to some $3.5 billion in asthma-related medical expenses. Furthermore, moisture can damage the building itself by creating an environment hospitable to insects and other destructive pests, corroding metal components and degrading wood and porous building materials. These problems can arise when water unintentionally penetrates the building envelope or leaks from indoor uses of water, or when moisture-heavy air condenses on building materials.

SOLUTIONS

Mold can find sufficient food and shelter on naturally present dust, so the best tactic to combat mold is to control the dampness of building materials. To minimize the negative effects of bulk liquid water, exterior sources of water (including precipitation and groundwater) should drain away from the building and the exterior cladding should block rainwater from traversing the building walls. In addition, the walls should contain capillary breaks to prevent water from wicking from outdoors to indoors; areas where condensation is likely to occur should use moisture-tolerant materials that dry quickly.

IMPACT

Through effective design of the building's curtain wall, plumbing assemblies and ventilation system, projects can make conditions inhospitable to mold, microbes and pests, reducing the risk to respiratory health.

REQUIREMENTS

Part 1

Manage Exterior Liquid Water (1 point)

Verified by Architect

For All Spaces

The following requirements are met:   

1. A continuous drainage plane (e.g., a weather-resistant barrier integrated with flashing systems at penetrations) is constructed interior to the exterior cladding.
2. To prevent the wicking of porous building materials, one of the below capillary break methods is used:
   1. Free-draining spaces (e.g., between exterior cladding, weather-resistant barriers in wall assemblies).
   2. Non-porous materials (e.g., closed-cell foams, waterproofing membranes, metal) between porous materials.

Part 2

Isolate Moisture-sensitive Materials (1 point)

Verified by Professional Narrative

For All Spaces

Moisture-resistant materials have been selected and/or moisture-sensitive materials are being protected, considering the following:   

1. Porous cladding materials.   
2. Finished floors and interior sheathing in basements, bathrooms, kitchens and high-humidity spaces.
3. Exterior glazing and entrances to the building from its surroundings.

Part 3

Manage Interior Liquid Water (1 point)

Verified by MEP

For All Spaces

To prevent leaks and water damage, one of the following is installed:   

1. Readily accessible, single-throw manual shut-off (governed or activated per use) or automatic shut-off at point-of-connection for all hard-piped fixtures (such as toilets, dishwashers, icemakers and clothes washers).   
2. Building-wide plumbing leak detection system.  

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