Soakaway Crates

Soakaway crates — also called geocellular crates or attenuation crates — are the modern replacement for rubble-filled soakaway pits, and a core component of any Sustainable Drainage System (SuDS). Their modular design offers a significant saving in excavation, soil transport and installation time compared to traditional methods. All of the soakaway crates we offer are held in stock in large quantities, competitively priced with bulk buy deals, and are available for next-day delivery!

Which Soakaway Crate Do I Need?

Not sure what type of crate you need for your project? Check out the helpful buying guide table below.

Crate Type	Suitable For	Load Rating Options	Storage Per Cubic Metre
Standard	Gardens, pedestrian areas and residential driveways.	20 Tonne (Naylor) 24 Tonne (Rainsmart Ellipse)	935 Litres (Rainsmart Ellipse) 950 Litres (Naylor)
Shallow	Areas with high water tables, and where holes are hand dug. They can eliminate the need for mechanised equipment to dig deeper holes.	24 Tonne (Rainsmart Ellipse) 65 Tonne (Rainsmart Heavy)	955 Litres (Rainsmart Ellipse) 984 Litres (Rainsmart Heavy)
Deep	Projects where there is limited lateral space and it is suitable to dig deeper rather than wider.	24 Tonne (Rainsmart Ellipse) 65 Tonne (Rainsmart Heavy)	1,043 Litres (Rainsmart Ellipse) 1,047 Litres (Rainsmart Heavy)
Heavy	Commercial car parks, property developments, stadiums and hospitals.	61 Tonne (Polystorm) 62 Tonne (Hydrocell) 65 Tonne (Rainsmart Heavy)	943 Litres (Rainsmart Heavy) 950 Litres (Polystorm) 984 Litres (Hydrocell)

Why Choose our Soakaway Crates?

Our comprehensive range allows us to offer the following benefits:

We supply leading UK systems including Polypipe Polystorm and Polydrain Hydrocell alongside our Rainsmart range, all engineered to industry-standard cellular crate specifications used across UK SuDS projects.
Flat-packed and fully assembled options are available, allowing you to decide whether to save on cost or time on-site
Our range covers load ratings from 20-tonne pedestrian and garden crates through to 65-tonne crates suitable for driveways and car parks, with heavier 80-tonne+ options available on request for HGV and trafficked-area projects.
We offer bulk buy deals on some of our most popular crate options, where the more you spend, the more you save
The modular design of Rainsmart crates has allowed us to create and offer kits for specific and niche drainage applications
All of our crates are lightweight and easy to transport on-site

Soakaway Applications

Our range of soakaway crates can be used in a variety of applications, including:

Underground stormwater management - to reduce flooding
Infiltration - allowing stormwater held in your tank to seep back into the ground slowly over a period of time
Attenuation - discharge water from crates slowly to avoid downstream flooding and erosion of waterways
Rainwater recycling - pumps the excess rainwater back out of the crate system for use in irrigation and reuse
Grass swales - linear grass-covered gullies which take surface water overland from the drained surface to a storage or discharge system, typically using road verges
Road drainage - enhancement in both quality and quantity of road runoff
Bioretention basins - using a channel (like a swale) stormwater can be slowed and treated to desired levels by the placement of check dams
Sportsfield drainage - assist with flooding and recycling by removing water and storing it underground for future use
Channel drainage - create a linear shallow open channel to funnel stormwater
Carpark stormwater tanks
Trench soakaway

Installing Your Soakaway Crates

Assembly is a simple process – the only tool required is a rubber mallet which we include with each cubic metre set. One person should be able to assemble a one cubic metre set in 12 to 15 minutes. Check out our video guide on how to assemble flat -packed crates for more information. We also have a step-by-step guide on soakaway crates installation, from excavating your hole, preparing the base and installing your crates.

What Size Should My Soakaway Be?

The design of a soakaway system depends on catchment area, soil permeability (typically established via a soil percolation test in line with Building Regulations Part H), water table clearance and foundation design. Soakaways are suited to sandy or loamy soils and should be avoided on clay or filled ground. For sizing, use our soakaway size guide and calculator, which lists the most popular configurations by roof and site area.

Soakaway Crates
FAQs
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Polydrain HydroCell 62 Tonne Soakaway Crate - 0.2 Cubic Metres
Code PDHCC60

Brand Polydrain

Style Assembled
5 stars From 1 reviews

£38.00 £45.60

Quantity:1-19 Ex VAT:£38.00 Saving:0%

Quantity:20-34 Ex VAT:£36.10 Saving:5%

Quantity:35-74 Ex VAT:£34.20 Saving:10%

Quantity:75+ Ex VAT:£30.40 Saving:20%

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Polydrain HydroCell 62 Tonne Soakaway Crate - 1 Cubic Metre Kit
Code PDHCC60M3

Brand Polydrain

Style Assembled
£175.00 £210.00

Quantity:1-3 Ex VAT:£175.00 Saving:0%

Quantity:4-6 Ex VAT:£166.25 Saving:5%

Quantity:7-11 Ex VAT:£157.50 Saving:10%

Quantity:12+ Ex VAT:£140.00 Saving:20%

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Polydrain HydroCell 62 Tonne Soakaway Crate with Silt Trap - 1 Cubic Metre Kit
Code PDHCC60M3K

Brand Polydrain

Style Assembled
£415.00 £498.00

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Do I need planning permission or Building Regulations approval for a soakaway?

Soakaways for residential properties usually fall under Building Regulations Part H, which covers drainage and waste disposal. A soil percolation test is normally required to confirm the ground is suitable — sandy and loamy soils typically pass, while clay and filled ground often don't. Planning permission may also apply if your project involves more than 5 m² of new impermeable surface, such as a driveway or patio. Check with your local authority before installation.

How do you build a soakaway crate?

If soakaway crates are purchased flat-packed, they will need to be assembled. The only tool required for this is a rubber mallet to lightly hammer the lugs of the small plates into the rows of holes on the large plate, and then the same for the remaining three large plates so that the crate structure is complete. Assembling a full cubic metre crate takes less than 10 minutes and should be done on a flat surface.

How are soakaway crates installed?

Once assembled, soakaway crates should be placed into a dug-out hole in the ground that is lined with a geotextile membrane. The membrane should then be wrapped around the crates before the hole is backfilled with a layer of sand or gravel followed by a layer of soil.

How deep should soakaway crates be installed?

When excavating a hole for a soakaway crate, the depth should be at a minimum 450mm deeper than the height of the crate you are installing. This will allow for a 150mm base layer of sand to be laid beneath the crate, and then 150mm of sand to be laid on top of the crate along with a 150mm layer of soil. The width and length of the excavated hole should be 300mm more than the dimensions of the crate, to allow for a 150mm backfill on all sides.

How long do soakaway crates last?

Correctly installed soakaway crates can last for decades without needing to be replaced.

How can you stop a soakaway crate from getting blocked?

The best way to prevent blockages is to install a prefilter before the soakaway crate in the drainage system. Silt traps or catchpit chambers are the most popular options for this, as they will catch soil and sediment and stop them from entering the soakaway crate.