Top Hat 225mm Twin Wall
Top Hat 225mm Twin Wall
Available to order
Code TH225TWW
Brand Cotterill Civils
- Diameter
- 225mm Twinwall
Couldn't load collection details
Total £65.00 ex VAT
Buying in bulk? Get a quote
Alternative sizes
The same item in other sizes. Each opens its own page and price.
- 150mm£38.00 ex VATAvailable
- 225mmThis one
Goes well with this
Tick what you need and add it all to the basket in one go.
Overview
Top Hat 225mm Twinwall
Top Hat pre-forms are designed to provide an effective and watertight seal around service pipe penetrations. This 225mm Twinwall Top Hat is ideal for use with twinwall drainage systems, providing a secure, watertight connection that prevents infiltration or exfiltration at service entry points.
Manufactured from durable materials, this product offers excellent resistance to ground movement, chemical exposure, and environmental conditions, making it suitable for stormwater, drainage, and infrastructure applications.
- Size: 225mm
- Type: Twinwall
- Application: Provides a watertight seal around pipe penetrations
- Ensures: Long-lasting and secure connection
- Suitable for: Drainage and stormwater systems
For technical advice or bulk pricing, call 0121 351 3230
More product information
Twinwall top hat connectors are available in 110mm or 225mm and are used for connecting inlet, outlet and vent pipes through impermeable membrane liners.
Top hats are typically bonded to the membrane layer using a double-sided duty tape between the top hat and the membrane, and 75mm PVC tape around the perimeter of the top hat.
These top hats are used as part of an attenuation and infiltration system where pipes enter the crate in order to create sustainable urban drainage solutions (SUDS).
Specification
| Product code | TH225TWW |
|---|---|
| Brand | Cotterill Civils |
| Colour | Black |
| Pipe size | 225mm Twinwall |
Delivery and collection
- Delivered across Great Britain on our own vehicles or by courier, depending on the product.
- Delivery is charged per delivery, not per item, by zone.
- Collect from Cotterills Birmingham Depot, near Junction 9 of the M42: Hermitage Farm, Grove Lane, Wishaw, B76 9QJ.
- Northern Ireland, the islands, the Isle of Man and the Channel Islands are quoted separately.
Questions about soakaway crates
What is the difference between a soakaway and an attenuation tank?
A soakaway lets rainwater soak into the surrounding ground, so the crates are wrapped in geotextile that lets water through. An attenuation tank stores the water and releases it slowly to a sewer or watercourse through a flow control, so the crates are sealed in an impermeable membrane. The same crates can do either job; the wrap and the outlet make the difference.
Can soakaway crates go under a driveway?
Yes, if the crate is rated for it. The 40 tonne StormMaster and 62 tonne Hydrocell crates are for driveways, car parks and other trafficked areas. The 20 tonne AquaVoid Home crate is for gardens and landscaping with no vehicles. Whichever you use, follow the maker's data sheet for bedding, backfill and minimum cover, or the rating won't hold.
How many soakaway crates do I need?
Divide the storage volume from your drainage design by the volume of one crate. A 1m x 0.5m x 0.4m crate is 0.2 m³ and a 1m x 1m x 0.4m crate is 0.4 m³. So 2 m³ of storage needs about 10 small or 5 large crates. Check the void ratio on the data sheet, as usable storage is slightly less than the crate size.
Do soakaway crates need wrapping in geotextile?
Yes. For a soakaway, wrap the whole crate structure in non-woven geotextile. It lets water pass into the ground but stops soil and silt getting into the crates. Our 4.5m x 10m Don & Low handy pack suits small soakaways. For an attenuation tank, geotextile is normally used to protect the impermeable membrane, not instead of it.
How far from a house should a soakaway be?
Approved Document H of the Building Regulations says a soakaway should not be built within 5m of a building or road, or in unstable ground. Building control or your drainage designer may ask for more, for example on chalk or where the ground slopes towards the house. Check the distance with them before you dig.
How much is delivery?
Delivery is priced by zone and charged per delivery, not per item. Enter your postcode above to see the price for your site, or see our delivery zones page.
Can I collect my order?
Yes. You can collect from Cotterills Birmingham Depot, near Junction 9 of the M42 (Hermitage Farm, Grove Lane, Wishaw, B76 9QJ), Monday to Friday. Choose collection at checkout.
Can I open a trade account?
Yes. Groundworkers, contractors and merchants can apply for a credit account online. Apply for a trade account.
Can you price a whole job from drawings?
Yes. Send us your site drawings and we'll do a free take-off and quote the full drainage schedule, with no obligation. Send your drawings.
Still unsure? Call 0121 351 3230 and talk to the team.
Reviews
What our trade customers say
Reviews are collected independently by REVIEWS.io from verified customers.
Buying for your business?
Open a trade account to buy on credit, with quotes for large and mixed orders.
- Credit account for regular orders
- Free drawing take-off and full quotes
- Delivery to site across Great Britain
Got drawings? We'll price the whole job
Send your site drawings and we'll do a free take-off and quote the full drainage schedule, with no obligation.