4 Signs You Need An External Basement Waterproofing Membrane

11 July 2023
 Categories: Construction & Contractors, Blog


A damp basement can be waterproofed via either an internal coating or an external membrane. Although excavation around the basement is necessary for the placement of an external membrane, there are several situations where it is the best option.

1. Rain-Related Seepage

Periodic water incursion following heavy rainfall, localized flood events, or heavy snow melt can't be prevented by painting waterproofing epoxy on the interior of the walls. There's often too much water pressing against the concrete foundation so a stronger membrane is needed. Installing an exterior membrane to prevent seepage in conjunction with an exterior french drain system to route excess water away from the foundation is a much more reliable option.

2. High Water Table

In areas with naturally high water tables and saturated soil, hydrostatic force can push excess moisture through the natural pores in a concrete basement foundation. The problem can be made worse simply because the saturated soil puts a lot of pressure on the walls, which may lead to cracks and even more moisture problems. Excavating around the foundation to put a waterproof membrane in place will help. Your waterproofing expert may also recommend backfilling the area with materials like sand and gravel to allow better drainage around the foundation.

3. Non-Structural Cracks

Small cracks in a foundation don't necessarily mean that there is major structural damage. Cracks that run vertically or diagonally are often minor issues caused by normal settling of the house or issues with uneven curing of the concrete when the foundation was poured. Unfortunately, these cracks can lead to water damage since moisture can find its way through them and into your basement. An external membrane will last the life of the home, and it will also ensure that no water gets into the cracks or into your basement. Cracks can then be patched on the inside for aesthetic purposes.

4. Constant Dampness

As mentioned previously, concrete is porous and any dampness in the surrounding soil can slowly seep into the basement. This can lead to higher humidity as well as mold problems. Minor damp issues can be counteracted by waterproofing the interior basement walls, but major damp seepage is better addressed with an exterior membrane. For those planning to finish the basements with drywall, paneling, and carpet, an external membrane is the best way to ensure that seeping dampness doesn't damage the newly refinished additions.

Contact a basement moisture waterproofing service to see if an external membrane is the right choice for your home.