If you’re thinking of buying a home with a wet basement this is right up your alley. There isn’t much more that will make a home buyer more nervous than a wet basement. So, lets take a quick dive into wet basements.
Older – pre 1970’s basements were not really designed to be finished basements. Most basements were built using unfinished expectations and construction standards.
Along comes a more modern era where every square foot of unfinished space is being eyed with the hope of being finished, livable space, and we run into a few challenges.
Older style stone and concrete block (CMU-Concrete Masonry Units) basement walls are built with porous materials. Brick, stone, concrete, and similar materials are porous. Porous means that the material will absorb water – like a sponge!
In today’s basement construction a heavy tar/bitumen type application is sprayed onto the outside of the basement before the builder backfills (puts dirt back around the foundation/basement walls) around the basement. This tar seals the exterior and prevents the porous material from coming into contact with the exterior moisture. Waterproofing wasn’t done to most homes prior to the 1970’s. And if it was – like everything else, as it ages, it stops performing like it did when it was new.
So where does that leave us?
Let’s first recognize that it’s the moisture outside the basement that’s the issue. Hydrostatic pressure to get technical! Understanding the buildup of water pressure helps us find the solutions. When the pressure is greater outside the basement than inside the basement, what’s outside is being pushed inside.
You need to know this:
1. Starting with the gutters; gutters that are missing, blocked, or in need of maintenance are a major cause of wet basements. Roofs can shed a vast amount of water and when gutters aren’t installed or acting as intended, they dump all that water at the outside of the basement walls.
2. Grading. Grading is another word for slope. When the grading or slope around a home is towards a home, it will carry surface water towards the exterior of the basement.
3. Saturation. We all have experience with a basement that has let water in during extremely wet periods. In a part of my own unfinished basement, when the exterior ground was heavily saturated, there was a pinhole sized hole that squirted water in like a small water pistol. Since fixed! When the ground is saturated due to heavy rainfall, thaw and freeze cycles or the water table, there is immense water pressure outside of the basement walls. This can lead to what is referred to as, “seasonal moisture”.
Most of what we see when looking at moisture in a basement is related to seasonal moisture. Can it or should it be addressed? We will dive into that next time. In the mean time if you need a thorough home inspection reach out to Ian at Smart Choice Home Inspection.