How Water Enters a Basement

Clogged or Missing Gutters and Downspouts

• A home's roof is a large collector of rainwater that must be redirected to the ground through gutters and downspouts. When gutters are clogged or in disrepair, rain falls off the roof close to the foundation where it seeps into the ground and collects under the basement floor and next to its walls. Clogged gutters also contribute to the rot of the roof's soffits. The rotted wood then fails to act as a barrier to the water and channels it into the interior of the walls where it naturally flows down to the basement.

Water Entry Through the Basement Floor

• Water that has pooled under the basement floor or along basement walls creates hydrostatic pressure that forces it to seep through cracks and crevices into the basement. Cinder-block walls will collect water in their cavities and not show evidence of water seepage until they overflow. During freezing temperatures the accumulated water in cinder blocks can freeze and cause additional structural damage to the walls and to the mortar as the ice expands. Loose mortar will weaken the structure and allow water to enter the basement.

Diverting Water Away From the Basement

• The first and best defense against water seeping into the basement is to direct it away from the property. Clean downspouts from the gutters should direct water into PVC tubing that directs it sufficiently far away from the property to prevent it from back-flowing toward the foundation. The soil should slant away from the house at the rate of six inches down over the first four feet away from the basement wall in order to stop excess water from collecting in the ground around the foundation. Clean fill dirt must be laid down and tamped at the prescribed slope. Top soil can be layered on top of the fill dirt with grass seed to prevent erosion.

Insulating Basement Walls

• In extreme cases of flooding, the basement walls' exteriors can be waterproofed by painting them with tar or another waterproof coating after they've been exposed by digging down to the foundation. An external "French drain" can also be installed next to the foundation to divert water away from the property.

In-Basement Solutions

• In the most extreme cases of basement flooding where external water remediation solutions have failed to resolve the problem, an internal "French drain" can be installed in a trough that has been cut into the basement floor. It will collect water from the basement's interior and redirect it to a sump pump where it will be pumped out of the property.