Explanation of When Footing Drains are Required

Understanding when footing drains are required is an essential part of maintaining the structural integrity and drainage performance of your home. Footing drains, sometimes called perimeter drains or foundation drains, are an underground drainage system designed to prevent water from pooling around the foundation. If you are noticing signs of a wet basement, leaks, or flooded areas around your home's foundation, installing footing drains may be necessary.

When Footing Drains Are Required for Homes

There are several clear indicators that signal the need for footing drains around your home's foundation:

• Consistent dampness or leaking in the basement
• Visible water accumulation or ponding near the foundation after rain events
• Wet spots or moisture stains on walls or floors in the basement or crawlspace
• A musty, mildew smell coming from the basement
• Cracks beginning to form in foundation walls or floors

If water is not properly draining away from your home's foundation, it can begin to seep through cracks and pores in the concrete. Even small amounts of water intrusion over time can lead to exponential decay. As water accumulates around foundations, it exerts hydrostatic pressure against basement walls and floors. This leads to bowing, cracking, and weakening of the entire structural integrity.

Inadequate drainage will also allow water to penetrate into basements and crawlspaces. This provides the perfect damp environment for mold, mildew, and rot to take hold. Not only does this create unhealthy indoor air quality, it also begins to degrade construction materials from the inside out.

Footing drains are required by most building codes for any buildings with usable living spaces below grade, such as basements or finished crawlspaces. The International Residential Code (IRC) mandates that foundation drainage systems be installed around all foundations that retain earth and enclose habitable or usable spaces located below grade. This includes basements, cellars, underfloor spaces, crawlspaces with concrete floors, and any living areas built partially underground.

How Poor Drainage Affects Foundations

To understand why proper drainage is so crucial around foundations, it helps to understand how water damage occurs:

• Saturated soil expands and contracts, exerting pressure on walls
• Standing water allows hydrostatic pressure to build up
• Water seeps through porous concrete and cracks
• Erosion wears away at foundation materials
• Water in soil dissolves minerals and deposits them on surfaces
• Wet conditions breed mold, mildew, and rot

All of these mechanisms lead to cracked, bowed, weakened foundation walls when water is not diverted away properly. The structural integrity of the entire building above is dependent on the foundation remaining strong and waterproofed.

Specific Home Features Requiring Footing Drains

While all homes can benefit from proper drainage, footing drains are especially critical for homes with the following features:

• Basements - requires drainage system around basement walls and under floor
• Crawlspaces - prevents water pooling and moisture damage
• Concrete slab foundation - drains water away beneath the slab
• Below grade living spaces - basements, underground rooms
• Poorly draining clay soil - retains moisture, exerts pressure

Having any fully or partially underground livable space almost always necessitates footing drains as part of the construction process. Soils with high clay content that drain poorly will also mandate footing drains to avoid foundation damage.

Identifying Drainage Issues That Require Footing Drains

Sometimes the signs of insufficient drainage around foundations can be subtle. It is important to thoroughly assess the landscape and look for any indicators that water is not properly diverting away from your home. Here are some steps to identify potential drainage issues:

• Inspect the ground around the entire foundation after heavy rains. Look for any ponding, puddles, or soggy soil near walls.
• Check for exterior signs like efflorescence or white mineral deposits that may indicate water is infiltrating.
• Monitor basement and crawlspace areas for musty smells, moisture stains, or mold growth on walls or floors.
• Hire an inspector to perform dye testing. They will spray specialized dye on the ground around the foundation and monitor for traces inside.
• Evaluate the slope and drainage in your yard. Proper grading should slope away from the house at a rate of 6 inches for every 10 feet.

Signs of Foundation Damage from Poor Drainage

Signs that drainage issues have already begun compromising foundation integrity include:

• Cracks in foundation walls, floors, columns
• Bowing or leaning walls
• Sagging floors or sloping surfaces
• Gaps around doors, windows, and frames
• Cracked or detached interior drywall
• Doors and windows sticking or not closing properly

Minor cracks can quickly expand into major foundation failures without proper drainage. Addressing any signs of damage right away is critical to stop further deterioration.

Professional Drainage Inspection

A drainage contractor can conduct further tests to diagnose problems accurately, including:

• Video camera pipe inspection to identify leaks
• Hydrostatic testing to check for water pressure on walls
• Flood testing by sealing walls and saturated ground
• Soil analysis to determine porosity and composition

Professional inspections can pinpoint the exact location of drainage issues around the foundation perimeter. This allows any repairs to be targeted for maximum effectiveness.

Installation Tips for Required Footing Drains

When footing drains are required, proper installation is key to maximize their drainage performance. Here are some best practices to follow:

• Layout your drainage system starting with downspouts and gutters, then use catch basins and solid piping around the perimeter to collect water.
• Choose perforated plastic drainage pipe with a diameter of 4-6 inches, and surround with gravel backfill material.
• Maintain a 2% slope down and away from the foundation walls to facilitate gravity drainage.
• Install the drain pipe below the footing about 6-8 feet below grade, but above the water table level.
• Daylight drainage pipe or connect to a storm sewer system. Avoid draining near septic tanks.
• Follow local building codes for proper permits and inspections during installation.

Excavation and Trenching Considerations

Proper excavation is crucial prior to pipe installation. Key factors include:

• Digging 6-8 inches below pipe elevation for gravel bedding
• Sloping trench walls at proper angles for stability
• Shoring trench walls in unstable or deep trenches
• Providing proper fill and compaction around pipes

Rushing the excavation process can undermine the entire drainage system. Planning this stage carefully to meet installation specs will pay dividends long-term.

Common options for dealing with collected water from footing drains include:

• Daylighting drainage - outletting water away from foundation
• Dry well - buries outletting pipe underground
• Connection to storm sewer - requires permit approval
• Sump pump system - pumps water up and away