French drains which, despite their name, originated in the United States, essentially work by providing invasive groundwater with a path of least resistance by way of which it can be redirected away from a structure or low-lying section of lawn. They are named for a new Hampshire man, Henry Flagg French, who, in 1860, published a book with the intriguing title: Farm Drainage – The Principles, Processes, and Results of Draining Land with Stones, Wood, Plows, and Open Ditches, and particularly with Tiles.
Nowadays, French drains are typically utilized to combat flooding problems caused by surface and groundwater that a house owner could be having, especially affecting their lawn, foundation or basement. They are also sometimes used to drain off liquid effluent from septic tanks.
The fundamental design, a gravel-filled trench, is straightforward but for it to carry on working on the long run, it’s important that it be executed.
Flooding troubles are usually connected with sloping ground, non-porous clayey soil, or a mixture of the two. As an example, in case your property is constructed on the slope together with your neighbors’ house occupying a whole lot higher up the slope, heavy rainfall can precipitate an accumulation of groundwater rushing down off their property and onto your own. Should your soil is struggling to absorb all of that water, you could very well experience harm to your house’s foundation, or leakage in to a crawlspace or basement underneath the ground floor of the house.
A linear French drain is a simple, inexpensive answer to such a problem. In this scenario, it behaves as a moat that protects your house by intercepting the groundwater rushing down the slope and directing it around and out of your house’s foundation.
A linear French drain is actually a doable D.I.Y. project, if you don’t mind performing some backbreaking work (this may involve digging a trench, which all things considered is a thing closely akin to a ditch) and you will have the appropriate tools and materials (1″ round washed gravel, 4″ PVC pipe with drainage holes, a trenching spade or power trencher and a builder’s level)
So, let’s get as a result of the nitty-gritty each of how to construct a French drain, and how it operates. To begin with, you’ll must dig an L-shaped or U-shaped trench system, 6″ wide and 24″ deep, 4-6 feet through the house. It’s important to not build the drain too nearby the house because, should you do, you’ll be bringing water against the cornerstone, which is precisely what you don’t want.
The main leg of the trench system needs to be dug up the slope from the house. For a U-shaped French drain, it should be level and linked to two pipes on either side of your home with 90 degree PVC elbow joints. For the L-shaped drain, the main leg should slope down, at a pitch of at least 1/8 inch per foot of fall, for the second leg that can run alongside the house, also connected by means of a 90 degree PVC elbow joint.
If you are designing your drain system, you need to make gravity work for you. Like a river, groundwater flows downhill, so you’ll have to work alongside natural slope of your home and, if possible, hold the exit pipe appear above ground to offer the groundwater a fairly easy exit point.
Once you’ve decided on the layout of the system and done the heavy work of digging the trenches, it’s time to install the working elements of the drainage system: the gravel and pipes. First of all, tamp down any loose soil in the bottom in the trench and line it with 1 to 2 inches of gravel, lay the PVC pipes on top of this first layer of gravel, with all the holes pointing down, and after that fill in the trench with additional gravel, to 1 inch below ground level. Then all you have to do is cover the trench with sod or sdxgas decorative touch of your choosing. And you’re done. The next time there’s a heavy rain, excess ground water will enter your newly installed French drain and stay diverted around your home and discharged after the exit pipe or pipes.
It’s commonly suggest that a French drain be lined with geotech fabric as well as the piping be wrapped in a geotech sock to stop it from becoming clogged with silt. I don’t recommend doing either. If you were likely to use geotech fabric anywhere, the area to put it would be on top of the trench to prevent silt and sediment from filtering down from above and filling inside the air spaces involving the gravel. Most of the water that enters a French drain is groundwater flowing sideways underground, not downwards through the surface. Groundwater will not be silty, it has already had the silt and sediment filtered from it since it trickled down with the topsoil. If you doubt this, just ask yourself whether underground spring water and well water are clear or muddy. Each of them are needless to say usually magnificent because soil is a natural water purifier.