Applied Building Science’s Crawl Space Protection System combines a tough moisture & radon-resistant membrane on the earthen floor with an insulating, moisture-retarding foam barrier on the exterior walls. This combination will keep your home warm, dry and odor-free for years to come.

A properly sealed, moisture-protected and insulated crawl space will increase comfort, save on energy costs, improve the durability of the home and reduce entry of moisture, radon, and other irritants or pollutants into your home.

The Problem
Crawl Space Dampness
Many homes have damp and musty crawl spaces. When moisture condensation on wood reaches certain levels, conditions are ripe for mold growth, structural damage and health issues.
 
Here are some of the common symptoms of a damp crawl space:

• Mold or moisture damage in the crawl space, living area or attic
• Musty odors in the living area
• Condensation (“sweating”) on air conditioning ductwork
• Condensation on water pipes or truss plates in the crawl space
• Buckled hardwood floors
• High humidity (even water droplets) in the living area
• Insect infestations
• Rot or failure of wooden flooring members

Some of the root causes of crawl space moisture problems are:

• Contact with or closeness to the earth.
• Humid air penetrating the area through open foundation vents
• Poor moisture management to drain rainwater and groundwater away from foundations
• Very high water table with no mechanical means of controlling it
• Moisture from interior plumbing leaks

Crawl Space Coldness
Many crawl spaces can be as cold as they are damp. In winter months, the temperature of an uninsulated or leaky foundation or footing wall can measure within a few degrees of the outside air. Heat from the living space will transfer to the colder surfaces below, making the floors above feel like an ice cube.

Here are some of the common symptoms of crawl space air infiltration & insulation problems:

• Cold floors against outside walls
• Frozen or burst pipes
• Heating system that can’t keep up during cold weather
• Drafts around floor registers, trap doors, or plumbing

Some of the root causes of a cold crawl space are:

• Air leakage (called convective loss) though gaps or cracks in wooden framing members above the foundation walls
• Cold air permeating (called conductive loss) the foundation wall from outside
• Foundation vents that are left open or won’t close
• Leaky or deteriorated access doors in the outside wall
• No mechanical means of heating the area.

How We Fix It
It is of little value to spend hundreds of dollars on a moisture-resistant covering for the ground & walls yet leave the perimeter walls uninsulated. Similarly, insulating the outside walls without the installing the proper ground cover can promote mold growth caused by the warmer environment in the crawl.

Applied Building Science’s crawl space protection system serves double-duty to keep the crawl and living spaces both warm and dry. First, we apply a durable, commercial grade, vapor-blocking polyvinyl membrane to the earthen floor. This material is both moisture and radon-resistant. All seams are overlapped & taped. The membrane is mechanically anchored to the perimeter walls.

Second, we spray a layer of two-part, closed-cell polyurethane foam to the perimeter walls. Our material has an R-value of 6.2 per inch and is moisture resistant. We also foam the rim joist cavities between the foundation wall and the living space above. This is most critical for sealing gaps in the lumber and concrete that allow cold air to chill the living space.

Third, we use spray foam to seal up any floor openings that communicate to the living space and attic.

Finally, for crawl spaces with outside entry points, we construct new insulated and weatherstripped crawl space access lids.

Cost
Applied Building Science’s Crawl Space Protection System generally costs 30-40% less than the franchise companies. Our vapor-blocking membrane and fire-rated spray foam products are robust, used extensively in commercial & industrial applications and designed to be long-lasting in service. Material Specification Data Sheets (MSDS) are readily available.

Floor versus Wall Insulation
For years, standard building practice was to insulate underneath the floor over a ventilated, unconditioned (i.e.: not heated) crawl space. Research now shows a better approach is to create a well sealed, unventilated, conditioned crawl space (much like a basement) by sealing and insulating the foundation walls rather than the subfloor.  Here’s why:

• Problems associated with ventilating the crawl space are avoided
• Less insulating material is required based on square footage of the subfloor versus the walls.
• Piping and ductwork can be brought into the conditioned volume of the house so they don’t  require insulation for energy efficiency or protection against freezing
• Heal loss and discomfort from gaps, settling or convective losses from fiberglass batt insulation in the floor cavities are eliminated.
• Air sealing between the living space and the crawl space is less critical.

To Vent or Not to Vent
For many decades, building codes and conventional wisdom have prescribed ventilation with outside air as the primary method of moisture control in crawl spaces. In the humid summertime conditions, however, ventilation with outside air only makes moisture problems worse. In winter months, homeowners forget to close foundation vents, leading to cold floors and frozen pipes.

Recent research by Advanced Energy Corporation (go to www.advancedenergy.org) and others indicates that a new type of crawl space system, with NO vents to the outside, can provide greatly improved moisture control and significant energy savings when properly installed.

Some local building codes in Michigan do permit unvented crawl spaces, subject to certain conditions. Check with your local code enforcement agency for further information.

Photos