DIY Network

Exterior French Drain Installation / Mold and Health From "Healthy Household Workshop" episode DHHW-102

What's tiny, toxic, fast-growing and possibly lurking in the walls and crevices of your home? Mold! While mold can be a serious health risk (causing everything from allergies to asthma and infection), there are steps to take to both prevent and eliminate.

Mold grows about anywhere (it's commonly found in foundations, walls, ductwork -- even attics), but it needs water to live. Moisture control is your best line of defense against this toxic invader.

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Exterior French Drains

• Can be installed underneath the foundation of a new or existing home.
  
• When placed around the perimeter of an exterior foundation can be effective mold shields.
  
• Work much like the drains underneath the home: water collects in the bottom of the drain and the downward slope directs the water away from the home.
  
• An ideal solution for homes near a water table.

Installing a French Drain

1. Trench should be no deeper than foundation and should be lined with garden fabric to keep roots out.

2. Fill with sand and gravel, then add a perforated pipe to concentrate the water and quickly carry it away. Wrap the pipe in more garden fabric.

3. Position the pipe in the middle of the trench and cover with gravel and sand.

4. A one-percent drop for every 100 feet of drain is enough to carry water away. In existing homes, drains should slope at least 45-degrees. Check slope with level and keep it consistent to avoid puddling of water.

5. Once trench is complete and French drain is positioned correctly, cover with packed gravel or landscape as desired.

Important: French drains are for underground water only; they don't replace run-off drains in the surface.

Health Factors:

Steve Klossner, from the American Lung Association, shares some of the health problems caused by mold.

• Allergic reactions - Nearly 30% of Americans have at least one family member with an allergy.

• Asthma - Mold is both a trigger and an exasperator for those suffering from asthma. Over 20 million Americans suffer from asthma.

• Additionally, infections and respiratory problem can be caused by mold.

Quick Tip: To control mold, keep the humidity in your home between 30-60%.