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To install an interior French drain, a waterproofing contractor cuts a channel into your basement slab around its perimeter. The contractor excavates the ground below the channel, installs perforated drain pipe and a sump pump well, and fills the trench with drainage gravel. The slab is patched with fresh concrete.
How deep should an interior French drain be?
French drain depth: About 8 inches to 2 feet deep should be sufficient for many water-diverting projects, though related systems, such as those built around foundations and sub-ground living spaces, as well as the bases of retaining walls, may be deeper.
Do Indoor French drains work?
Exterior French drains function to divert water around the exterior perimeter of your house. Interior French drains, on the other hand, function to divert and carry away water and moisture out from the interior of your basement. This is one of the most effective systems for treating severe damp problems in basements.
What is an indoor French drain?
A French drain (also called a weeping tile, drain tile, perimeter drain or sub-surface drain) is a common basement waterproofing solution. It’s a trench containing a perforated pipe that redirects surface water and groundwater away from the foundation.
Does French drain need an outlet?
A properly designed French drain system does not require an outlet. The water will simply soak into the soil as it flows along the perforated pipe. In fact, a French drain doesn’t require an inlet on just one end either.
Why do French drains fail?
Over time, a French drain may become clogged. Tiny soil and clay granules slip through the pores of the landscape fabric and gradually build up inside the pipe. Another common cause of French drain clogs is root intrusion from grass, shrubs, and trees.
How long does an interior French drain last?
Water will run through the gravel for the first 10 to 20 years before the iron completely clogs up the gravel and reaches the piping. Piping is installed with holes facing upward and clean outs are also installed on each wall. With proper maintenance, your French drain will last a lifetime.
How deep does a French drain need to be for a basement?
The trench should be at least 2 feet wide, and can be as deep as 6 feet for a basement or as shallow as two feet for a slab-on-grade home. Lay the pipe on the virgin soil.
Do I need a sump pump or French drain?
Activates When Needed French drains are passive, which means there is nothing to ‘turn on’ during a heavy storm or flood. Sump pumps on the other hand activate as soon as the float starts to rise. This means that as long as the pump can drain more water than can enter the pit the basement will not flood.
Do French drains cause mold?
French drains are only installed on properties prone or likely to flood. These systems collect water and move it away from the basement walls so it won’t penetrate. If it does, it can cause damp, mold, structural damage, and more problems. For these reasons, it’s important to stay on top of maintaining a French drain.
Do interior perimeter drains work?
They are located directly on top of the footing around the perimeter of your basement. This prevents it from draining to the center of the basement floor where it could pool and cause lasting damage. Interior drains work with Sump Pumps (defined below) to effectively keep basements dry and protected from damage.
What can I use instead of a French drain?
5 Alternatives to French Drains Sump Pumps. Dry Wells. A dry well can add drainage without the need for an electrical or sewage line connection. Stairs, Steps or a Ramp. Landscaping. Valleys or Ditches. Gutters.
Do French drains actually work?
Properly constructed, french drains will work well to transmit water from the pipe to the exit of the pipe; however, they are not very efficient in dewatering poorly drained soils. Adequate fall means at least 2 ft lower per 100 ft of pipe or 0.25 in. per foot of slope.
Will a French drain prevent water in basement?
In fact, it keeps the basement dry by preventing the water from developing the pressure it takes to enter the basement in the first place. A French drain, often called “drain tile,” installed inside or outside the foundation, will keep most basements dry and never requires maintenance or replacement.
Why is there a trench around my basement floor?
Normally, there is a perimeter trench around the floor that allows any water that seeps through the walls to flow down between the walls and the floor to the under-slab drain lines. The holes will allow water to flow into the trench around the basement rather than building up within the wall.
Can you finish a basement that has a sump pump?
By the way, I recommend a sump pump for ALL finished basements, even if the pit is dry. Install a check valve in the vertical pipe line from the pump; it prevents water from sliding back down into the pit after the pump shuts off.
Where should I put my French drain outlet?
A properly designed French drain system does not require an outlet. The water will simply soak into the soil as it flows along the perforated pipe. In fact, a French drain doesn’t require an inlet on just one end either. You can construct the drain to accept water along its length, and disperse it underground.
Can I cover a French drain with dirt?
Can I cover a French drain with dirt? Because a French drain has holes throughout the pipe which allow it collect water, you should not install dirt on top of the drain pipe. Installing dirt will clog the pipe and the holes, rendering it useless.
Where do French drains run to?
As mentioned a moment ago, French drains ensure any rainwater in outside your property will flow away from the building. The liquid runs into a gravel trench and then flows into a pipe at the bottom of the drain. The water travels through the tube and then empties somewhere safe away from the house.
