• Home
  • DIY
    • Self build
    • Projects and advice
      • Bathroom
      • Building, brickwork and masonry
      • Ceilings
      • Cleaning
      • Concrete work
      • Damp, rot and infestation
      • Drains
      • Electrical
      • Fireplaces
      • Floors
      • Garden
      • Heating
      • Insulation
      • Kitchen
      • Lighting
      • Lofts
      • Painting and decorating
      • Plasterwork
      • Plumbing
      • Roof and guttering
      • Safety
      • Security
      • Tiling
      • Walls
      • Windows
      • Woodwork
    • Glossary
    • Know your tools
    • Know your materials
  • Cost guides
  • News
  • Community
Facebook Twitter Instagram
lets-do-diy.com
  • Home
  • DIY
    • Self build
    • Projects and advice
      • Bathroom
      • Building, brickwork and masonry
      • Ceilings
      • Cleaning
      • Concrete work
      • Damp, rot and infestation
      • Drains
      • Electrical
      • Fireplaces
      • Floors
      • Garden
      • Heating
      • Insulation
      • Kitchen
      • Lighting
      • Lofts
      • Painting and decorating
      • Plasterwork
      • Plumbing
      • Roof and guttering
      • Safety
      • Security
      • Tiling
      • Walls
      • Windows
      • Woodwork
    • Glossary
    • Know your tools
    • Know your materials
  • Cost guides
  • News
  • Community
lets-do-diy.com
You are at:Home»Projects and advice»Installing French drains

Installing French drains

LAST UPDATED: 9th January 2023 by The Editorial Team

Installing French drains

Summary: Step by step guide and video showing how to construct a French drain.

Contents

  • How to build a French drain
    • Constructing a French drain
    • Tools needed
    • Materials needed
  • How a French drain works video

    How to build a French drain

    A French drain is a simple and efficient form of drainage that requires no pipe work. Water collects in a trench filled with gravel or stone, preventing ground surface water from penetrating foundations. The French drain will carry water away from the wall or property to a soak away. French drains are also often used to drain water away from retaining walls or from the outlet of a septic tank. Though easy to construct you may need a surveyor if you don’t think you can get the gradient right. You may require planning permission for the drain but if not, the drain must still comply with building regulations.


    Constructing a French drain

    • The drain must end in a soak away (see constructing a soak away).
    • First choose the best location for your soak away where water draining off a slope could be redirected, ideally an out-of-the-way area with sandy soil.
    • Check for underground cables or pipes in the area. You may need to consult your local service providers.
    • Plot the direction of your trench with stakes and a string line.
    • The drain normally begins just below the surface and runs at a gradient to the soak away. If there is no natural drainage slope, you will need to create one to direct the water. A grade of 1 in 100 is recommended i.e. a drop of 300mm (1ft) for every 30m (100ft) in length.
    • The trench should be a minimum of 150mm (6in) wide.
    • Line the trench with ground sheeting. This allows water to pass through but not soil which can block the drain over a period of time.
    • Fill the trench to within 10mm (1/2in) of the top with clean stone or 20mm (4/5in) gravel.
    • Wrap the ends of the sheeting over the top of the stone or gravel.
    • The top of the trench can then covered with a layer of sand and topsoil.

    Tools needed

    • String line
    • Spade
    • Shovel

    Materials needed

    • Ground sheeting
    • Clean stone OR 20mm Gravel
    • Sand
    • Topsoil

    How a French drain works video

    Summary: DIY video showing you how a French Drain works.

    A common mistake is to place the holes on a French drain at the highest point. The video will talk you through where to place the drainage holes within the pipe and why it is important to have the towards the bottom.


    Author

    The Editorial Team

    The Editorial Team at lets-do-diy.com are a team of experts led by Mark Wilson. We have been creating DIY projects, articles, costs guides and product reviews since 2008. For more info see our about page.

    Related projects

    • Drain unblocking
    • Driveway and patio drainage
    • Soak away
    • Soak away for sewage effluent

    Related cost guides

    • Average cost of a septic tank
    • Average septic tank cleaning cost

    Recent Comments
    • Vic on Is Christmas a good time for DIY?
    • Anonymous on Average air source heat pump cost (2022)
    • Reggie on Prepare your home for moth season
    Latest News
    0

    Potential DIY home improvement trends for 2023

    1

    Is Christmas a good time for DIY?

    0

    Design trends for 2022 and 2023

    0

    Product Review: Handsaws

    Popular Guides

    Average cost of decking

    8 useful hand tools for the garden

    Average tennis court cost

    Average cost of fitted wardrobes

    Popular Projects

    Erecting close-board fencing

    Building a partition wall with concrete blocks

    How to remove grout

    Wiring low voltage spotlights

    DIY Categories
    Bathroom
    Building, brickwork and masonry
    Ceilings
    Cleaning
    Concrete work
    Damp, rot and infestation
    Drains
    Electrical
    Fireplaces
    Floors
    Garden
    Heating
    Insulation
    Kitchen
    Lighting
    Lofts
    Painting and decorating
    Plasterwork
    Plumbing
    Roof and guttering
    Safety
    Security
    Tiling
    Walls
    Windows
    Woodwork

    Self Build Guide
    How to find a building plot
    Evaluating a building plot (2023)
    How to get a self build mortgage
    Self build construction options
    Self build architect and design considerations (2023)
    Self build planning permission and legal consents
    © 2023 lets do diy ltd | ebuild
    • Home
    • About
    • Contact us

    Type above and press Enter to search. Press Esc to cancel.

    We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept All”, you consent to the use of ALL the cookies. However, you may visit "Cookie Settings" to provide a controlled consent.
    Cookie SettingsAccept All
    Manage consent

    Privacy Overview

    This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.
    Necessary
    Always Enabled
    Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously.
    CookieDurationDescription
    cookielawinfo-checkbox-analytics11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
    cookielawinfo-checkbox-functional11 monthsThe cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
    cookielawinfo-checkbox-necessary11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
    cookielawinfo-checkbox-others11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
    cookielawinfo-checkbox-performance11 monthsThis cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
    viewed_cookie_policy11 monthsThe cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.
    Functional
    Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features.
    Performance
    Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors.
    Analytics
    Analytical cookies are used to understand how visitors interact with the website. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc.
    Advertisement
    Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. These cookies track visitors across websites and collect information to provide customized ads.
    Others
    Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet.
    SAVE & ACCEPT