How to Externally Waterproof a Basement

A house foundation

Externally waterproofing your basement foundation while providing drainage is the best protection from water damage. It is usually done when a house is being built, but you can waterproof the exterior foundation walls of your home as long as utility lines and other structures don't impede your access to the walls below ground. Waterproofing involves installing French drains around your foundation to direct the flow of underground water away from your house. Waterproofing without proper drainage is futile. You can also apply waterproofing compounds made from urethanes that can be sprayed on your foundation to provide added protection from water seepage.

Things You'll Need

• Shovel
• Work gloves
• Wheelbarrow
• Portland cement
• Pump sprayer
• Polymer-based sealant
• Ground sheeting
• Pea gravel
• Downspout extenders
• Topsoil

Send to Phone

Brought to you by

Send to Phone

Please enter your 10 digit phone number only.

Send

A link to this article has been sent to the phone number provided.

Close

Reply HELP for help, STOP to end. Message and data rates may apply.

Instructions

1. Dig a trench around the foundation of your home with a shovel. Dig down to the footing.

2. Make sure that there are no large cracks in the wall. Apply a Portland cement-based waterproofing seal with a trowel to fill any small cracks and re-seal mortar joints. If you have cracks larger than hairline cracks, you should call in a professional contractor to assess the damage and repair it properly.

3. Spray a polymer-based sealant with the pump sprayer on the foundation walls to prevent future cracking.

4. Install a French drain with a slope that takes the water away from your house. To do this, dig the trench around your foundation so it slopes 1 inch for every 10 feet away from your foundation. The gravity will pull the water away from your house. End the trench in an area where the water can drain away and dissipate without damaging your neighbor's property.

5. Line the trench around your foundation with ground sheeting.

6. Fill the trench with pea gravel up to a few inches from the top of the trench. Wrap the sheeting around the pea gravel.

7. Shovel a layer of topsoil on top of the sheeting and, if you like, plant bushes or plants around the foundation to cover your work.

8. Install gutter extenders to your down spouts to drain water away from your foundation.

References

• Wet-Basement-Waterproofing: Waterproofing your basement
• Ask the Builder: Exterior Foundation Wall Waterproofing
• National Waterproofing Systems: Exterior Waterproofing