LANDSCAPING FIGHTING FLOODING WITH FABRICS
Vernon Elsey, director of landscaping and building materials supplier Growtivation talks BMJ through some do’s and don’ts for creating resilient outdoor spaces.
T
he start of 2026 has been ‘exceptionally wet’ in the UK, according to the Met Office. By early February, many areas had already experienced more than their typical total winter rainfall, and experts were warning that the risk of flooding remained high in many locations.
One of the major factors increasing flood risk is urbanisation: covering green space with tarmac and concrete, which speeds up the flow rate and quantity of surface water running into drainage systems and water courses. In turn, this increases the risk of flooding, either locally or further downstream.
It’s not surprising then that national government, local authorities, insurers and organisations such as The Flood Hub are urging households to increase the permeability of their gardens, for example by swapping concrete driveways for permeable paving or gravel. At the same time, homeowners are looking for ways to reduce waterlogging in their gardens, for instance by installing French drains or soakaway crates.
Whether constructing drives, drains, soakaways or even rain gardens, it is vital to select the right landscaping fabric. Many types allow some water to pass through, but the rate at which it does so varies hugely and can be the difference between an area draining or turning into a small lake during a period of intense rainfall.
Paving over gardens An audit of the UK’s gardens by the Royal Horticultural Society (RHS) in October last year found that 55% of domestic front garden space and 36% of back garden space is now paved over. The RHS also noted that artificial grass, which also prevents rainwater from soaking into the soil, is increasing in prevalence.
There have been suggestions that homeowners should be penalised for paving over their gardens. ‘The London Climate Resilience Review’, published in July 2024, proposed that the UK government consider charges for those paving over gardens and incentives for removing paving and, although this idea has not been taken up.
What many people may not realise is that paving more than 5sq m of a front garden requires planning permission – unless the surface is permeable; for instance gravel, permeable paving or reinforced grass. This planning rule was
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Above: Soakaway crates, surrounded by a non-woven geotextile such as Draintex, can prevent waterlogging in gardens by storing surface water and then allowing it to infiltrate slowly into the ground
Above: French drains can protect gardens from flooding and house walls from damp. Trenches containing perforated pipes are lined with a non-woven geotextile such as Growtivation’s Draintex.
www.buildersmerchantsjournal.net March 2026
introduced in 2008, although it does not set out required values for permeability and drainage rates and is rarely checked or enforced.
For now, national and local governments are aiming to encourage people – rather than pay them – to make their gardens more permeable. As well as permeable driveways and paths, there are other means of doing that such as French drains, land drains, soakaways and rain gardens. These are often referred to as SuDS – sustainable drainage systems – because they mimic the way that rainwater would naturally enter the soil, were there no development in the area. If a landscaping fabric is marked as ‘SuDS compliant’ this means that it is highly permeable, allowing water to drain through it at a rate similar to natural ground absorption.
Why non-woven?
Whether installing landscaping fabric under a gravel or permeable paving driveway or wrapping a soakaway crate before backfilling with shingle, it is best to use a non-woven geotextile rather than a woven one. This is because non-woven geotextiles, which are manufactured through thermal bonding or using needle punching, allow a far faster drainage rate than woven ones.
For instance, Growtivation’s Groundtex woven fabric enables a water flow rate of around 0.05 litres per m2 per second. Meanwhile, its non- woven Drivetex and Draintex fabrics both have a permeability of 120 litres per m2 per second. For a permeable driveway, gravel is the most effective choice in terms of drainage rates. And, if installed using a grid system such as Gravelrings
Non-woven geotextiles such as Growtivation’s Drivetex and Draintex (left) allow water to pass through them far more quickly than woven fabrics such as Groundtex (right).
which prevents movement and rutting of the gravel, these require less maintenance than permeable paving or reinforced grass driveways. If an existing asphalt or concrete driveway is to be replaced, it may be possible to re-use the sub-base and membrane beneath it. However, it is important to check whether a geotextile membrane has been installed and what type it is. Without any membrane, the angular type 1 subbase will be pressed into the soil over time. And, as explained above, a woven fabric may not allow water to drain away fast enough. Permeable paving can be a good choice for patios, again requiring a non-woven geotextile and subbase beneath it. It’s important to note that water passes through the gaps between pavers, rather than through the concrete or stone of the paver, so these gaps must be cleaned of weeds and sediment from time to time to maintain the flow rate.
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