The majority of homes today are built with poured wall basements, which are far less likely to need basement waterproofing, but that wasn’t always the case. Most homes built prior to the 1970s rest on cinder block foundations. The main difference between the two is evident in their names: poured walls don’t have joints and are thicker than block walls, meaning they can better resist water pressure. Block walls are crafted with cinder blocks and can hold more weight on top of the foundation. But there are some common issues that tend to affect them, which could in turn lead homeowners to need basement waterproofing.
The hollow cavities of cinder blocks can be a problem. If water has come up against the foundation wall, it’ll start pouring into those cavities. At that point, the water is only 2-2.5 inches away from entering the basement. Unlike poured walls, which offer 8-10 inches of protection, the thickness of cinder blocks is only a couple inches. On top of that, the porous nature of cinder blocks lets humidity in too. The main takeaway is that due to the hollow cavities in the blocks, moisture and water have much shorter paths to getting in and wreaking havoc on your basement.
Age itself is not an issue, but a factor. Old Michigan homes are highly likely to have block wall basements. If you live in any of the following cities – some of the oldest in Michigan! – there’s a good chance your basement is built with block walls:
Block walls are more susceptible to caving or bowing, in part due to the fact that mortar joints are weak points which can deteriorate from exposure to water. If water is filling up outside the foundation because the system is not draining properly, it’s going to start pushing the wall in and you’re going to start seeing horizontal cracks where it is concaving or bowing the most. (Check out our Encyclopedia of Cracks for helpful information on cracks of all kinds.)
Pesky moisture content is always a potential issue, but it’s significantly more likely to occur in block wall basements. One sign that you’re dealing with high humidity is efflorescence, a white, powdery material that grows on concrete when moisture wicks through. If humidity is 55% or higher at any point, per the EPA, your basement is probably home to airborne mold growth and humidity-loving insects. Many people will try to combat this with a dehumidifier, but by the time they realize they need one, it’s too late to really make a dent in the moisture problem.
With block wall basements, we almost always recommend including a vapor barrier as opposed to just a drainage system. The wall liner works to encapsulate the basement wall; it’s so thick, it’s effectively a pool liner for your basement walls. Vapor barriers are installed from top to bottom on the wall and then tucked into the drainage system, effectively covering the entire block wall itself. Not only does it hold fast against water coming in, but it keeps out moisture as well. Moisture will always wick through concrete because it’s a porous substance, so if you have a block wall basement, a vapor barrier is a waterproofing must.
All crawl spaces are constructed from block walls. As they are much closer to the surface than basements, they have a much higher likelihood of experiencing these issues. Something as simple as a sprinkler hitting the house could cause water problems. In general, it’s just easier for water to get into crawl spaces.