Rainsmart Ellipse Shallow 20 Cubic Metre Soakaway

This soakaway set automatically qualifies for 10% off through our spend and save discounts!

Our 20 cubic metre shallow soakaway system coming flat-packed.

You will need 160 shallow crates which we would recommend laying 16 crates wide by 10 crates long. This will give you a complete soakaway of 6.4m (W) x 7.15m (L) x 0.44m (D).

A rubber mallet for assembly and a number of cable ties will also be included to join the crates together and to clamp the membrane around your pipe entry points.

Assembly of this set really is a quick and easy process - full instructions are included and you can view a quick video on assembling shallow flat-packed soakaways below.

Size, load and capacity

The dimensions of the complete soakaway are 6.4m (W) x 7.15m (L) x 0.44m (D)

Rainsmart soakaway crates have a void ratio of 95% - this is the amount of free space within the crate structure that can be used for rainwater storage. The capacity of this 20 cubic metre soakaway is an impressive 20,150 Litres.

The vertical crush load capacity of 24.2 tonnes per square metre ensures that the Rainsmart Ellipse crates are safe to be used beneath the grass, under pedestrian areas or in light traffic. The lateral crush load of 18 tonnes per square metre is the best of any type of soakaway crate currently available in the UK.

Joining crates together

Clips are not required to hold the crates together. No clips on any crate system are structural it is always the side fill on any soakaway installation which adds the stability needed to hold the structure in place. Cable Ties are included with our 20m³ Soakaway Sets and these are used to connect two sides of the complete soakaway together in an L formation (the other crates are then jammed into this corner). These ties are used purely to hold the crates in place until the sand or gravel side fill has been added.

Geotextile & Damp Proof Membranes

We stock a number of membranes that will be needed for your installation - depending on the design. A non-woven geo-textile membrane will be needed in order to ensure that no silt or soil particles enter the crate. If you don't want infiltration to occur from the soakaway you will also need to install an outer layer of impermeable - this will prevent water from leaving the soakaway.

Our membranes come in 4.5-metre widths and can be purchased by the metre or in 100m rolls. For this soakaway, we would recommend that you buy a roll, in order to ensure you have enough coverage, but as a guide, you will need approx. 30 metres of the 4.5-metre roll. 

Inspection & Cleaning

For best practice, we always recommend that a pre-filter such as our Sentinel Silt Trap is used in conjunction with any modular soakaway system. Emptying the filter on a regular basis (this is only a five-minute job) will maintain the efficiency of the soakaway and greatly increase its lifespan.

All outward-facing crate surfaces of any soakaway should be wrapped in a non-woven geotextile membrane, which allows the free passage of water but prevents any soil or sand particles from entering the soakaway, maintaining its long term efficiency.

Flow Control with Attenuation

With the increase in emphasis on SuDS local planning authorities and specifiers are implementing flow control systems to prevent flooding. Through attenuation rainwater is released back into the network, but in order to ensure you aren't passing any potential is downstream this is done so at a controlled speed. Check out our Flow Controls page for more information about Orifice Chambers & Valves.

Connecting Pipes to Soakaways

The 110mm (or 160mm) drainage pipe is fed into the soakaway via the entry plate. Geotextile membrane should be installed over the opening first and then a small cross should be cut in the membrane at the entry point with a sharp knife. Carefully peel back the membrane, insert the pipe and tape or clamp the membrane tightly around the outside of the pipe to stop the ingress of any soil particles.

For a closer look at Soakaway Crates in general, please take a look at our introductory video.