5 Crawl Space Waterproofing Mistakes
Here are 5 crawl space waterproofing mistakes many contractors and homeowners make when correcting a flooded crawl space. The time, money, and effort it takes to repair a flooded crawl space is significant. Don’t waste these resources by making these crawl space waterproofing mistakes and having to redo the project.
Mistake #1 – No Sump Pump Basin
The sump pump basin is what houses and protects the sump pump. Properly installing a sump pump basin will keep your sump pump secure and clean for years. We recommend a perforated basin to allow groundwater to enter quickly. The faster the water enters the basin, the quicker it can be discharged from the crawl space.
Waterproofing Mistake #2 – No Sump Pump
The second mistake is trying to get the water out of the crawl space using a gravity-fed system. Many contractors will punch a hole in the foundation wall beneath the crawl space vapor barrier as a discharge point. This type of discharge can get bogged down when your crawl space takes on water after a heavy rain.
Keep in mind as your crawl space is flooding the groundwater is rising outside the crawl space. This can create competition for your gravity-fed system, especially if you are using a perforated pipe outside the crawl space. I have yet to see a contractor transition from a perforated to a solid discharge line at the foundation wall.
Add a crawl space sump pump every 140 linear feet on the interior of the crawl space. This will give the waterproofing system the power it needs to remove flood waters quickly from your crawl space.
No Vapor Barrier – Mistake #3
Not having a vapor barrier and not having a properly installed vapor barrier will affect the crawl space waterproofing system’s performance. We use a properly installed crawl space vapor barrier the same way a basement waterproofing company uses concrete. The encapsulated and sealed plastic keeps the water in a position for it to reach the crawl space waterproofing system.
Loose laid vapor barrier will shift when the crawl space floods. Once the water is on top of the plastic, the waterproofing system becomes useless to remove that water. Keeping all floodwaters under the crawl space vapor barrier will direct water to the sump pumps and interior drainage system.


