Installing Crawl Space French Drain Tips

Do you need crawl space french drain installation tips because your crawl space floods after heavy rains or there is a body of water close to your home? What I will be sharing today are guidelines for properly installing a waterproofing system in your crawl space.

Install the Drain Pipe Around the Entire Crawl Space

If you are taking on water in your crawl space, there is a possibility the entire foundation wall is wet whether you see it or not. Many homeowners and contractors only install the drainage system in the are they see standing water.

Avoid Future Drainage Problems

We recommend a full perimeter trench system in the crawl space to take care of the problem now and any potential future problems. No one wants to reinstall the vapor barrier 5 years later after a gutter floods and creates a pathway for flood water to enter your crawl space.

Pro Tip – In some cases you may need to install a french drain in the center of the crawl space and attach it to the perimeter. This is effective in areas close to big bodies of water like on the coast or near lakes. The water table in the soil is always high and can enter the center of the crawl space and float the vapor barrier.

Sump Pumps and Battery Back-ups

We do not usually use gravity to run the water out of the crawl space once it enters the french drain system. For us, using sump pumps attached to battery backup systems is a more reliable, long-term approach. Over time we have seen landscaping companies and homeowners forget where gravity discharge lines are and sometimes destroy them. Running a 1.5-inch PVC discharge to a pop-up emitter is less difficult to forget because it is always visible.

Of course, the time you will lose power is when you need it the most, during heavy flooding. The SEC 822PS Pump Sentry is great for pumps up to 1/2HP and the 1622PS covers up to 3/4HP. Both are great add-on battery backup systems to ensure your sump pump runs when it is needed the most. The Pump Sentry can be installed on new and existing systems in both crawl space and basement waterproofing applications.

Improve Your Sump Pump Water Discharge

Pro Tip – Make sure you are installing your sump pump into a sump pump basin with weep holes to allow moisture to enter. You can even dead-end the pipe into the basin to make sure water enters and is discharged faster.

Install the French Drain Near the Surface

We see articles and DIY guides advising homeowners to bury the french drain pipe at the footer in crawl spaces like you would in a finished basement, but keep in mind the main enemy is surface water. If you place the drainage system at the footer and you live in a hard soil or clay environment, the vapor barrier may float, or worse the water gets on top of the plastic before it has a chance to seep into the footer drain.

In crawl spaces, our primary concern is groundwater which can come from the footer, the foundation wall, or the door. Making sure the flood water has easy access to the drain tile you placed in the crawl space will ensure it discharges quicker to the outside.

Pro Tip – Make sure you weigh down the pipe if it is covered with a Styrofoam aggregate otherwise it can float out of your trench. Don’t use loose polystyrene foam poured into the trench because it will float out under your vapor barrier.