Note that i said the drain pipe must be sloped rather than the french drain.
French drain depth uk.
The width and depth of the drain you dig will depend on the severity of the drainage problem and the digging tool you re using.
Traditionally the most common are up to 6 inches wide and 12 inches in 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.
However most standard french drains are approximately 6 wide and 18 to 24 deep.
However some situations may require trenches several feet deep and several feet wide.
This low level distribution pipe will have no outfall.
The depth of the french drain depends on the purpose for using it and the location.
When it comes to working out the best size for your french drain there is usually no need to make it larger than around two feet deep and one and a half feet across.
There is no hard and fast rule regarding the depth of a french drain.
These french drains often also include a lower level perforated pipe to distribute the water along the length of the french drain trench.
A french drain pipe can help divert water away from your home s foundation patio or low lying areas to help prevent damage or pooling water.
Further information and standard details of french drains with high level overflow pipes can be found in our french drain detail post.
All of your drain pipe with one exception must slope slightly downhill.
When installing a french drain next to a structure the trench must go no lower than the lowest foundations.
Recommended depths can range from about 18 inches to 6 feet.
That should be more than enough to ensure the drain can handle any moderate amount of rainfall.
Trenching tools will cut wider trenches which is ideal for more severe drainage issues and will cut the digging time in half.