***Hand excavated french drains are a must for hillside home sites
Hand excavated french drains are a must for hillside homes. Some of the most common building sites to experience groundwater problems are located in areas with significant slope. The high side of the home is most often the point of water entry due to the fact that the topography of the site slopes groundwater to the home when it is raining hard. French drains, specifically hand excavated french drains are the most effective method of groundwater removal available to homeowners with these problems.
This is true especially in areas where dirt or clay soils are the dominant type. Areas where loose rock is the main ingredient in the site are much more challenging. I will deal with that subject in another article.
I want to address the hand excavation of french drains on hillside locations with clay or dirt as the main ingredient in the topography because this is the most common type of drainage problem in our area.
Areas where I have found uncharacteristic drainage problems are usually hillside locations where loose rock has been used to create a more structurally stable area on which to build when compacted. This is an unfortunate endowment for the homeowner even though it is a fortunate fact that the homeowner can then build on a site that would not permit building without the rock for stability.
The trouble with loose or compacted rock areas are created by engineers, builders and county-city governments who do not take groundwater drainage into consideration or who under estimate the problem and/or do not understand it.
The homeowners are damaged by groundwater that can run through the rock into basements and crawlspaces. Clay and dirt soils contain the water from the sides and below on a hard surface to run the water away on a slope prior to saturation and the hydrostatic pressure that causes the leaking.
In areas where native soil or clay is the major ingredient, the french drain construction remains conventional with respect to materials and methods. The most effective french drain installation method envolves the creation of an aquaduct with a grade of approximately 2″ per 10 lineal feet or greater. The distance in lineal feet is measured to assess the available drop in grade to a proposed drywell or daylighted vent.
Areas around the foundation that are flat or have topography that slopes toward the home will benefit most from french drain installation. There may be other areas that are affected due to other problems such as foundation vents too low and on the ground level where the water can run into the crawlspace. Gutter systems are many times a problem as well.
The good news is that sloped properties usually are easier and cheaper to deal with if the distance to wheel barrow rock uphill does not impact the manhour aspect of the job proposal too much. In some cases the slope may be brutal, and the cost more expensive than a typical flat site, but in the long run the sloped sites allow the water more of an enhanced ability to run away from and around the building site.
The flat sites are actually more problematic in that they must have french drains installed that are designed with distances around 50 ft. in length with specific grade requirements to make them work in optimal form. Usually more drywells are needed as well on these flat areas as a result of having to split up the distance and create grade through the flat areas.
Hillside locations are most often prone to slides and other problems such as slumping if not treated with the installation of french drains. Install french drains, specifically hand excavated french drains to protect your home site and prevent slides and foundation cracking due to saturation and hydrostatic pressure caused by rainwater and the groundwater problems that it produces.
Read this website for more information on groundwater problems, french drain installation, and the best ways to protect the value and infrastructure of your post-beam and foundation. Install hand excavated french drains.