Do You Need a French Drain Installation? Read This First
Do you struggle with pooling groundwater or poor drainage around your yard? If so, you may need to install a French drain to improve drainage, divert water away from your garden, protect your home’s foundation, and improve the look of your landscape. In this article we tell you how to install a French drain, why you should, and where to get professional help.
What is a French Drain?
A French drain is a fancy-sounding name for what is a sloped trench that holds a perforated pipe and some gravel. The first French drains were gravel-filled trenches that drained water away from an area and into a catch basin. A
A French drain in a basement is a shallow trench that pulls water into a perforated pipe that is attached to a sump pump. Henry French (hence the name) made the first basement French drains popular, and they are still the best method for drying out basements where moisture is a continuous problem.
Do You Need a French Drain in Your Basement?
Most basements are below ground, making them more prone to moisture intrusion. Long-standing moisture presents many challenges, including mold and a breeding ground for bacteria. Almost all new homes include a basement drainage system, but older homes built before the latest building codes may not.
Not all basements have a moisture problem, but if you suffer from a “wet” basement, water and saturated soil may put pressure on your foundation. Concrete is porous, so the moisture will eventually leak through into the basement. In extreme circumstances, the water pressure may even crack the concrete. The French drain collects the water into a collector basin where a sump pump can then transfer it away from the property.
Moisture also attracts rodents, so the first step to good rodent control in your basement is to keep it as dry as possible.
Types of French Drain Installation Piping
There are two types of piping used in French drains. The first is a rigid PVC pipe with predrilled drainage holes placed about 6 inches apart. The second is a flexible perforated drainpipe with slits.
PVC is more durable, and it’s easy to clear a clog with water pressure or a plumber’s snake. Flexible pipes are cheaper and easier to work with when going around corners. A good tip when working with PVC is to attach a 45-degree angle that sticks out of the floor to create an easy access point for pressure cleaning.
When you lay the pipe, always ensure the drainage holes a pointing downwards. This might seem counterintuitive, but French drains work by allowing water to seep into the drainage holes from below.
How to Install a French Drain
Building a French drain for your garden landscape to drain water away from your property is straightforward. However, installing a French drain in your basement is a big project and is recommended only for experts. If you have building or maintenance experience, here are the steps to installing a French drain.
Mark out the Location
Mark the start of your French drain about a foot away from the exterior wall in a location that gets the most moisture. This is an ideal location to place the sump pump that will transfer water to the outside drainage system.
Dig the Trench
The next step for installing a French drain is to dig the trench. A good-sized trench will be about 8 or 9 inches deep and between 18 to 19 inches wide. You will need a jackhammer to break through the concrete to get to the soil underneath. Dig out the rest of the soil with a shovel.
The bottom of the trench will need to slope gently so gravity can drain the water naturally towards the basin. Tamp the soil down with your shovel and make sure the bottom surface drops an inch for every eight feet of trench. A trench that is 32 feet long will need to be 4 inches deeper at the end than at the start.
Fill the Trench with Gravel
Place some gravel along the bottom of the trench before laying the pipe. This will help support the pipe and prevent soil from clogging the drainage holes.
Place the French drainage pipe into the bottom of the trench while making sure the perforations are pointing downwards. Run the pipe along the entire length of the trench and attach it to the water collection basin. Make sure the connections are watertight to prevent drainage problems.
Fill the trench with gravel. Moisture will seep through the gravel to the bottom of the trench and up through the drainage holes where it will collect in the pipes. From there, it will flow down the pipes and into the collection basin, where the sump pump will expel it outside and away from your home. Don’t fill the trench with gravel all the way to the top because you’ll need some space for concreting in the last step.
The last step to installing a French drainage system in your basement is to seal it with cement. If your drainage issues are caused by water rising from below, you should seal the entire trench. If moisture comes in through cracks in the walls, a 2-inch gap will allow moisture to flow into the drain.
Sump Pump Installation
A sump pump installation is an effective solution for removing moisture from your basement and away from your home. However, sump pumps work best when they are installed along with a French drain that funnels water into the sump pit. Position the sump pump in the lowest corner of the basement where water naturally pools for the best results.
Hydrostatic pressure in your basement can lead to expensive structural repairs in your basement. When soil is oversaturated, the water pressure will strain your foundation and walls. Eventually, they may crack. A good French drainage system prevents the soil from becoming oversaturated, so you won’t risk your home’s structural integrity. Call the professionals at Attics Pro today to find out more on how a French drain can keep your basement dry and rodent free.