Filter and Envelopes

filter and drainage

Over the years, the French drain has received many, albeit subtle upgrades. Continuous innovations in the agriculture and landscaping industry have benefited even the drainage system. The addition of filters in the system is among these minor but nonetheless effective changes. Improvements made on the envelopes are another. Each addition improved the efficiency, but in its core, the French drain remains more or less the same.

French Drain Filters

Filters used in the French drain are typically permeable, non-woven fabric materials that help keep out smaller debris and soil particles. It will help the drain last longer by keeping the perforated pipe from being clogged. It can also prevent clay from depositing in the spaces between the gravel, disrupting the flow of water.

One example of this filter commonly used today is the landscaping or weed control fabric. It became popular for use in French drains during the 1970s. It was originally used in gardens and plant beds, intended as a physical obstruction against the growth of weeds. With its permeability and durability, it has since found other uses, including in French drains.   


The landscaping fabric is one of the two types of geotextiles. The other one is known as the drainage or drain field fabric. While the two types share similar construction and the characteristic of permeability, they serve different purposes. The landscaping fabric is used for landscape applications, whereas the drain field fabric is used in septic drain fields. Other uses for geotextiles are in road construction projects and soil erosion control.   


Envelopes are the materials used to fill up the trenches and surround the perforated pipes in the French drain. These are pieces of gravel, stones, or rock that add permeability to the drain system. The loose spaces in between the fragments facilitate the flow of water while blocking large particles from clogging the perforated pipe. In situations where the soil condition is unstable, the envelopes are a stabilizing presence, supporting the sides of the unstable soil and preventing them from caving in.

The most common type of envelope used in French drains is the granular minerals. Coarse sand, fine gravel, and crushed stone are mainly used. If designed well enough, they can work adequately despite significant soil deposits. Together with the filter, it could ensure drain functionality for many years.

Other types of drain envelope are organic and synthetic envelopes. The former are mostly agricultural byproducts, while the latter are yarns and similar materials loosely pre-wrapped.     

French Drain Contractors

We at A-1 Drainage & Excavation who installs French drains near me understand that, with the busy schedule of most homeowners, adequate drainage at home often becomes an afterthought. It is something that seldom gets needed attention until water has seeped into the basement or your yard has turned into mud. In short, when the damage is already done.

Let our team of professionals help. We can assess your existing draining system and recommend the best way to incorporate the French drain and make sure things are flowing smoothly. Call us now, and we would make sure that your home will never have to know flooding, standing water, and muddy yards.