Last Modified: February 9, 2024

Membrane Plastic Under Gravel

OUR "PEOPLE ALSO ASK ABOUT" SERIES

Membrane plastic under gravel

By Ben Parrot - Landscape Gardener & Amateur Geologist

Overview

In this edition of the 'People Also Ask About' series, we will explore frequently asked questions around the topic: "Should I put plastic down before gravel?" These questions are are commonly searched on Google and highlight the confusions about the best practices for what to put down when laying gravel outdoors. Our article aims to provide clear, expert advice on this topic to assist you in making informed decisions when it comes to landscaping with decorative aggregates. Please look for your specific question in the quick links menu.

Pea shingle on geotextile plastic. Jpg

Key Takeaways

  • What types of plastic are used for mulching?
  • Learn the difference between plastic sheets and landscaping fabric.
  • The different approaches to laying gravel on soil.
  • Methods to stop decorative aggregates sinking into the ground.
Planter with shrub and plastic mulch under slate chip. Jpg

Landscaping with Gravel

Gravel is a super versatile material to use when landscaping and garden or constructing buildings and other types of outdoor structures. It's also very good for creating bases and foundations, which are a vital part of building features for a traffic weather pedestrian or vehicular. In this section, we answer the questions surrounding the use of gravel as a foundation and as a ground cover. We have a lot more on the versatility of gravel in our deep dive into the twenty one Gravel Landscaping Applications. Let's get straight to your questions.

Can I Lay Gravel on Top of Soil?

Yes, laying gravel directly on top of soil can be approached in a few ways:

  1. 1
    Compacting the soil prior to laying down the aggregate.
  2. 2
    Utilising plastic membrane sheets presents an alternative to landscape fabric for weed suppression.
  3. 3
    Employing landscape fabric to inhibit weed growth.

In general, for any application beneath gravel, rocks or other forms of hardscaping materials, landscape fabric is recommended for low maintenance. It prevents weed growth, aids drainage and provides a structure for your gravel feature.

Should You Put Anything Under Gravel?

In general, you should provide some kind of foundation if you want a long-lasting and durable result. As a minimum, we advise good soil compaction prior to laying chippings, if you do not intend to lay some kind of plastic membrane between the soil and your aggregates. A sub-base is a must for gravel driveways and paths, as without one, the lifespan and durability would be greatly reduced.

A base layer often consists of crushed aggregates like MOT type 1, or compacted soil, which provides a stable foundation. Incorporating an additional geotextile fabric between the base layer and the gravel can also prevent weed growth, aid proper drainage and keep the gravel separate from the soil, helping to preserve the aesthetic and structural integrity of the surface for many more years than one without a barrier.

Excavated garden ready for gravel laying scaled. Jpg

What Membrane Goes Under Gravel?

The ideal type of plastic membrane to place under gravel is a high-quality landscape fabric or heavy duty weed membrane. These membranes are specifically designed to allow water to permeate through while preventing weed growth and soil mixing with the gravel. Opting for a permeable, durable landscaping fabric helps the gravel remain clean and stable, reducing maintenance needs and improving the overall appearance of your landscape design.

What is the Best Fabric for Under Gravel?

If you are laying in areas without traffic, the most cost-effective choice for fabric under gravel is nonwoven, specifically spun-bound fabrics. These fabrics serve as an effective weed barrier. They help to maintain a uniform appearance for your gravel path, preventing the stones from sinking into the soil, improving the path's durability and appearance.

How Do You Lay Plastic Under Gravel?

This question often relates to the installation of gravel stabilisation grids. To lay plastic gravel grids under gravel effectively:

  1. 1
    Start by preparing the site, ensuring it's level, compact and free from roots and debris.
  2. 2
    Roll out a non-woven geotextile membrane across the area, securing it in place with landscaping pegs.
  3. 3
    Begin placing gravel retention grids at one corner, interlocking them as you proceed across the prepared area.
  4. 4
    Once the grids are in place, fill them with gravel, compacting them slightly to ensure a stable, even surface.

This method not only prevents weed growth but also ensures the gravel remains neatly in place, particularly with pea gravel or on sloping areas. Beginning with this foundation will improve the longevity and appearance of your landscaping project.

Gravel stabilisation grid for golden gravel driveway

What Plastic Do You Put Down Before Gravel?

The type of plastic sheeting recommended for use under gravel is a heavy-duty HDPE (High-Density Polyethylene) roll. However, this is mostly for use as a mulch for weed eradication, as it would not suit landscaping applications where you intend to use gravel as mulch for your flowering plants or shrubs.

This type of plastic sheeting is available in various thicknesses ranging from 30 mil to 100 mil. It is waterproof, UV resistant and non-biodegradable, making it a sound choice for both residential and commercial landscaping projects. Its durability and resistance to environmental factors provides a long-lasting, maintenance-free gravel surface without weed growth.

What Do You Put Down Before Laying Pebbles?

Before laying pebbles, it's advisable to install landscape fabric on the prepared ground to avoid a lot of maintenance in the future. This type of membrane acts as a barrier, separating the stones from the soil and preventing weeds from sprouting between the pebbles while allowing water to drain through. Ensuring the area is free from sharp objects before laying the fabric is essential to avoid punctures, reducing future maintenance issues.

Heavy duty weed membrane

Need to work out how much gravel your project needs? Try our free gravel calculator.

Do I Need to Put Something Under Gravel?

In this section, we look at the various questions related to laying gravel in the garden.

How Do You Lay Plastic Under Gravel?

To lay plastic under gravel effectively, begin by preparing the sub-base of your gravel driveway or path to ensure it can support heavy loads and provide a flat, solid foundation, which is especially important for uneven surfaces. After the sub-base is prepared, a weed membrane should be laid over the topsoil and beneath the gravel. This membrane, also known as landscape fabric or geotextile, is crucial for blocking weed growth while allowing water to drain through, thereby maintaining the integrity and appearance of the gravel surface. It's recommended to choose a durable, permeable fabric that can withstand the conditions under the gravel, ensuring a long-lasting and low-maintenance gravel area. For more detailed guidance, we offer step-by-step instructions on installing landscape fabric in How To Lay Chippings.

What Do I Put Under Gravel to Stop Weeds?

Installing a weed membrane is highly recommended to prevent weeds under gravel. Placed directly on top of the soil and beneath the layer of slate, gravel or chippings, it effectively blocks sunlight and prevents weed seeds from germinating. Weed membranes are also easy to install and offer a clean solution to maintain the aesthetic appeal of your gravelled areas.

Weeds growing up through slate chippings garden. Jpg

What Should I Lay Down Before Gravel?

Before laying gravel, it's essential to prepare the ground to ensure stability, separation from the soil and optimal weed prevention. Start by compacting the soil with a tamper to create a firm base, which helps prevent the gravel from sinking or shifting. You can use a hand tamper for small jobs or a roller or plate compactor for jobs likely to experience traffic. They only cost ~£50 per day to hire.

After compacting the soil, lay down landscape fabric as a weed barrier, preventing weed growth through the gravel while enabling excellent drainage and separation from the soil, maintaining the integrity and appearance of your gravel surface.

How Do You Keep Gravel from Sinking into the Ground?

To prevent gravel from sinking into the ground, the use of a geotextile fabric membrane is the most highly effective strategy. When placed between the gravel and the soil, it acts as a stabilising layer that separates the two. It also improves the driveway's durability by distributing the load more evenly, ensuring that the gravel remains in place, reducing the frequency of replenishment, and making it a cost-effective, low-maintenance solution.

Making eyelet holes in plastic sheet. Jpg

What Do You Put Under Gravel for Drainage?

For optimal drainage under gravel, non-woven geotextile fabric is the preferred choice, as it offers superior drainage over the woven varieties. This fabric, available in various weights, is designed to allow water to pass through while filtering out sediment, thus preventing clogging and ensuring stable ground beneath the gravel. Its felt-like texture provides an excellent combination of drainage, filtration, and soil stabilisation, making it an ideal underlayment for gravel paths, driveways, and landscaping projects.

Summary

In summary, we have explored alternatives to plastic sheeting and provide comprehensive answers to help your gravel landscaping project stand the test of time. Laying plastic beneath gravel has many benefits such as weed suppression and moisture management. However, it depends on the specific needs of your project, including the area's intended use, local climate, and soil type. It is not suitable for use in decorative borders where plants require drainage and the interchange of minerals and gases.

Gravel mulch and decorative stone garden

We have every type of gravel available to choose from in the UK. Check them out!

About the author 

Ben Parrot is a landscape gardener and amateur geologist. He is the founder of Outdoor Aggregates, with the mission to create the first encyclopaedia for decorative aggregates. From natural stone through to decorative bark, these aggregates are critical to garden and landscape design, universally.

The problem: There isn't any place where all the different types of decorative landscaping materials and construction aggregates can be found, nor are the specifications of each type readily available. So, enriched by his extensive experience, and inspired by the timeless elegance and raw beauty of stone and rock, etched by nature's artistry over millennia, Outdoor Aggregates was born.