Soakaway crate membrane wrap
Updated: October 2026
You have plastic infiltration crates in the pit and a roll of fleece beside them, and every face, including the pipe, has to be closed or the surrounding soil will wash into the void. A soakaway crate membrane wrap is that non-woven jacket. It is not a second buying guide, and it is not a French-drain trench. How the trench that feeds the crates is lined sits on [how to lay drainage fleece](/hub/weed-control/drainage-fleece/sub/drainage-fleece-how-to-lay). Which cut matches the area sits on [best drainage fleece](/hub/weed-control/drainage-fleece/sub/drainage-fleece-best). Shelf prices remain on the [drainage fleece comparison](/hub/weed-control/drainage-fleece). This page was updated in October 2026 from those listings and from public UK crate guides. We did not install a soakaway or run a lab test. If you buy through our links, a qualifying purchase can earn us a commission at no extra cost to you.
You have plastic infiltration crates in the pit and a roll of fleece beside them, and every face, including the pipe, has to be closed or the surrounding soil will wash into the void.
You have plastic infiltration crates in the pit and a roll of fleece beside them, and every face, including the pipe, has to be closed or the surrounding soil will wash into the void. A soakaway crate membrane wrap is that non-woven jacket. It is not a second buying guide, and it is not a French-drain trench. How the trench that feeds the crates is lined sits on how to lay drainage fleece. Which cut matches the area sits on best drainage fleece. Shelf prices remain on the drainage fleece comparison. This page was updated in October 2026 from those listings and from public UK crate guides. We did not install a soakaway or run a lab test. If you buy through our links, a qualifying purchase can earn us a commission at no extra cost to you.
Our top picks
| Badge | Product | Cut size | Cover area | Main use | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Spudulica Spudulica 1.1 m x 8 m | 1.1 m x 8 m | 8.8 m2 | Soakaway trench and border | 9.8 | about £29.55 | View offer |
| Alternative |  Spudulica Spudulica 2.25 m x 3 m | 2.25 m x 3 m | 6.75 m2 | Soakaway crate wrap | 9.0 | about £26.02 | View offer |
| Preis-Tipp |  Spudulica Spudulica Caisse 2.25 m x 8 m | 2.25 m x 8 m | 18 m2 | Soakaway crate underlay and drainage layer | 9.0 | about £37.55 | View offer |
On this page
Why the crates are wrapped
An infiltration crate is a plastic void that lets water into the surrounding ground. The fleece is there so silt does not travel with that water and fill the void. Drainagepipe.co.uk describes non-woven geotextile on all the outer faces. Growtivation’s crate article specifies a non-woven such as Draintex, and it sets that against a woven sheet such as Groundtex. The woven weed membrane is the wrong wrap. It is built to block light, and it is a poor filter for a crate that has to keep accepting water. The wrap is not a waterproof skin. Polystorm’s guide treats permeable geotextile as the layer over the modules, and a geomembrane as a separate sheet when the tank must contain water. Principal’s notes make the same split. If you are building an attenuation tank, follow the tank instructions and use the impermeable sheet they name. Drainage fleece on its own will let that stored water out. Concrete ring soakaways are a third detail. BRE Digest 365, as carried in the UNDA note we used, separates granular fill from the soil with geotextile and says not to wrap geotextile around the outside of the ring units. The fleece belongs around the stone, not as a jacket on the rings. Copying a plastic-crate wrap onto a ring soakaway fights that guidance. This page sizes neither your roof nor your crate volume. If the soakaway serves a building, building control is part of the job, and English notes such as CNC Building Control discuss siting, including a 5 m figure from buildings and roads. That figure is not claimed here as the rule in every UK nation.
Faces, overlap, and the pipe
Cover every outer face: bottom, sides, ends, and top. Drainagepipe.co.uk allows two sequences. You can place the crates onto geotextile that is pushed down as they go in, or you can assemble the crates and wrap them afterwards. Either way the soil should meet fleece, not bare crate. Leave the top until the pipe is in, then close it, or you will be cutting a hole through a finished lid and trying to seal the scrap. The overlap depends on whose sheet you are installing. Principal’s crate notes use 150 mm. Polystorm’s geotextile line is about 200 mm over the modules. Draintex’s trench sheet, which is a different detail, says a minimum of 300 mm. Use the figure for the product in the pit. A 150 mm lap on a system whose drawing says 200 mm is a shortfall, and averaging the three numbers invents a fourth detail nobody published. Weight or tape the laps so they stay closed while you backfill. Soil packed against an open seam is a path into the void. The pipe entry is the gap people leave. Drainagepipe.co.uk describes the membrane at the inlet taped or clamped so the pipe passes through a sealed hole rather than a slit that gapes. Cut the hole to the pipe diameter, bring the fleece back onto the pipe, and fix it. A slit with two flapping edges lets silt in at the one place the water is concentrated. The same care applies if two crates meet and the joining faces are outside the wrap: the outer jacket is continuous, and the internal tunnel between crates stays open.
How much fleece to cut
The Spudulica 2.25 m by 3 m cut is 6.75 m² of stated 100 gsm fleece, listed at £26.02, and the listing says that area wraps one 190 litre storm crate. A UK review used the same piece on two stacked Polystorm crates measuring 400 by 500 by 1,000 mm. That review is a tighter fit than the one-crate line once you add overlap, so a larger stack needs more fabric. Do not treat 6.75 m² as a universal crate allowance. A single small crate with modest laps can land inside it. Two crates, a 200 mm lap on every seam, and a pipe flap can use it up. Step up when the stack grows. The 2.25 m by 6 m cut is 13.5 m², and the 2.25 m by 8 m Caisse cut is 18 m², which is the best value in this set when you want more square metres for several faces. Those still do not publish a flow rate or a puncture figure. Confirm gsm on any piece whose specification table omits it. The 2.25 m by 10 m listing is the one where a UK review reported an 80 gsm stamp against a 100 gsm advertisement, so it is a poor crate wrap until you have read the fabric in your hands. Choosing the cut by width and stated weight, before you are in the hole, is the drainage fleece buying guide.
When to stop and get advice
Stop and bring in a professional when the crates take roof water from a building, the pit is close to the house, the ground needs a digger, or you need a declared strength the listing does not provide. This page does not tell you to skip building control, and it does not calculate a crate volume for your roof.
Common questions
Should the wrap be woven or non-woven?
Use non-woven geotextile. Growtivation’s crate article specifies that construction and sets it against a woven weed fabric. The fleece has to pass water and hold silt. A black weed membrane is the wrong jacket, even if the title says heavy duty. An impermeable geomembrane is a different product again, for a tank that must store water rather than infiltrate it.
Do you wrap the top as well?
Yes. Drainagepipe.co.uk puts non-woven geotextile on all the outer faces, and the top is one of them. Soil above the crates will move downward if the lid is open. You can wrap after assembly or lay the sheet and push it down as the crates go in. Leave a proper lap at the lid, using the overlap in your crate guide, rather than a single thickness stretched tight.
How do you seal the pipe?
Cut a hole close to the pipe diameter and tape or clamp the fleece back onto the pipe, which is the method Drainagepipe.co.uk describes. A knife slit that is wider than the pipe leaves a gap where the inflow is strongest. Do the same if a second pipe leaves the crate. The internal connection between two crates stays open. Only the outer soil faces are closed.
Is 6.75 m² enough for one crate?
The listing for the 2.25 m by 3 m cut says 6.75 m² wraps one 190 litre crate. A UK review wrapped two stacked Polystorm crates of 400 by 500 by 1,000 mm in that same piece, which is tight once overlap is added. If your crates are larger, or you are following a 200 mm lap, buy more area. The label is not a measurement of your pit.
What overlap should you copy?
Copy the figure in the guide for the crates you are installing. Principal’s notes say 150 mm. Polystorm’s geotextile line says about 200 mm. Draintex’s trench sheet says 300 mm, and that sheet is for a trench, not automatically for your crate. Using one of those numbers on a different system is how the wrap ends short at the corner.
Should a concrete ring soakaway be wrapped?
BRE Digest 365, in the UNDA extract used here, says to keep geotextile around the granular fill and not to wrap it around the outside of concrete ring units. A plastic crate is the opposite case: the crate itself gets the non-woven jacket. If your pit is rings and stone, follow the ring detail. The 6.75 m² crate claim does not transfer to that build.
When does building control get involved?
When the soakaway takes drainage from a building, your local authority’s building-control process is the route, and this page does not replace it. English notes discuss distance from buildings and roads, including a 5 m figure, and that figure is not stated here as the rule in Scotland or Northern Ireland. Bring a contractor in if the pit is close to the house, needs a digger, or needs a datasheet the listing does not print.
Related pages
Sources
Public UK sources from the research digest. Shelf prices and star lines are the amazon.co.uk figures in the product listings used for this page. gsm, permeability and puncture lines are listing claims or review notes, not a test run for this page.
- Approved Document H: drainage and waste disposal (retrieved October 2026)
- CNC Building Control: soakaway size FAQ (retrieved October 2026)
- BRE Digest 365 via UNDA (retrieved October 2026)
- BS EN 13252:2016 geotextiles for drainage (retrieved October 2026)
- AGS: BS 8661:2019 geotextile guidance (retrieved October 2026)
- Geoworks: where to use geotextiles (retrieved October 2026)
- EasyMerchant: geotextile membranes explained (retrieved October 2026)
- Growtivation: fabric for wrapping soakaway crates (retrieved October 2026)