Basement Waterproofing

Waterproofing your basement is a vital step in protecting your home from water intrusion and from water-related damage, and it’s also the very first step when finishing a basement.

The Importance of a Dry Basement

Having a dry basement is important for preserving the integrity of the house’s structure and for keeping items like furniture, appliances and valuables safe.

A dry basement is also important for increasing additional living space. When remodeling the basement for use as a home office, recreation room, guest bedroom or rental apartment, the basement must be dry in order to install walls, flooring, ceilings and electrical and plumbing systems.

5 Potential Reasons for a Wet Basement

Wet basements can be caused by interior reasons, such as condensation or leaky pipes, or by exterior reasons, like groundwater or poor drainage.

Interior Condensation

When the air in the basement is too humid, water can condense on the walls and floor. Water can also condense on the walls when there is a sharp temperature difference between cold walls and warm air.

Cracked Foundation Walls

When foundation walls are cracked or have holes, water can seep in from groundwater or from on-grade water.

Windows and Doors

Water can migrate into the basement through basement windows and doors. Water can also leak through upper-floor windows and doors, through the walls and down to the basement.

Leaky Pipes

Basements usually contain the majority of a home’s mechanicals: furnaces, AC units, pipes, water heaters and more. Water supply pipes run through the ceilings of basements and can leak.

Groundwater

Groundwater is water that has soaked into porous soil through dirt, sand and rocks. Groundwater may come up through a basement floor or from the side, through foundation walls.

Waterproof a Basement From the Inside

Fill Cracks

Cracks in basement foundation walls can be filled with hydraulic cement, Sikadur epoxy resin . It then expands to fill the crack.

Seal Walls

If a moisture tester indicates that water is seeping through the basement walls from the outside, a masonry waterproofing product can be applied to stop the moisture. Two coats of the waterproofer can act as a barrier against trace amounts of external water.

Add Interior French Drain

An interior French Drain is a trench in the floor of the basement that provides a channel for water to flow to a sump basin. Filled with perforated pipe and gravel, the French drain diverts water away from other parts of the basement and to the sump pump basin, where the sump pump expels it to the outside.

Waterproof a Basement From the Outside

Grade the Yard

Grading the yard sends exterior water away from the foundation and the basement. 

Install or Improve Gutters

Gutters capture roof water runoff and direct it away from the foundation and the basement. Most homes need gutters. 

Seal Exterior Foundation Wall

Basement foundation walls can be sealed against water with a liquid synthetic membrane, solid sheets of bentonite or synthetic sheet membrane. A cementitious coating can be applied to the outside of the basement walls for extra moisture protection.

All exterior foundation sealing methods require soil to be dug out from alongside the foundation wall to the bottom. Drain tile may also be added to the bottom of the trench to help with drainage.

Install Exterior French Drain

A French drain is a trench lined with gravel, perforated pipe and weed-block fabric. Water enters the trench and is moved to the end of the pipe, away from the foundation and basement. French drains work well for yards where pooled water seeps toward the basement walls.