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Althon design and manufacture precast concrete headwalls to meet Sewers for Adoption and Severn Trent Guidelines. Our product range includes flap valves, penstocks and stop logs as well as trash screens and outfall safety grilles. Althon also manufacture precast concrete penstock chambers and offer a large range of commercial and industrial application drainage channels.


Mag Group Building
Vulcan Road South

Precast Concrete Headwalls

Althon precast concrete headwalls offer a cost effective alternative to in-situ headwalls. We have the largest range of precast headwalls with associated accessories in the UK. We have ranges of Sewers for Adoption 7th Ed., Severn Trent Water specification compliant headwalls and Angled headwalls to meet the Environment Agency's Standard rule SR2015 No 27 – Constructing an outfall pipe of 300mm diameter through a headwall into a main river’.

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Precast Concrete Headwalls

Headwalls are an important part of most SUDS drainage schemes, preventing erosion at the point of discharge into watercourses such as attenuation ponds, detention basins, rivers, ditches and swales.

All of our headwalls can be factory fitted with a range of accessories such as gratings, Kee Klamp® handrails, flap valves, penstocks as well as other flow control and flood prevention devices.

Standard Precast Concrete Headwalls

Althon's standard concrete headwalls are fast and easy to install. Our standard range of headwalls can accommodate pipework up to 2100mm ID. We can cast multiple openings, elliptical, square or rectangular culvert openings into any of our outfalls. We can also cast pipe openings into the wing walls. 

Sewers for Adoption (SFA) Headwalls

Althon Sewers for Adoption precast headwalls should be used when part of a Section 104 Agreement and the sewers are to be adopted once completed by the local Water Company. The materials used and installation must comply with the ‘Sewers for Adoption’ guidelines.

Our Sewers for Adoption compliant outfall range is available with toe extensions either 300 or 500mm thick with depths ranging from 450 to 1000mm. We also manufacture Sewers for Adoption compliant outfall safety grilles suitable for our products as well as other third party concrete outfalls.

Rectangular Sewers for Adoption (RSFA) Concrete Headwalls

Althon Rectangular STW Headwalls are Sewers for Adoption compliant precast concrete headwalls for outfalls discharging into ponds, swales, ditches beaches and rivers. RSFA precast headwalls are manufactured in accordance with Severn Trent Water Standard detail STD6002 for pipework up to 600mm All RSFA Headwalls are cast with the opening in the back wall to suit the size and type of pipe being used at the invert level required.

Angled Precast Headwalls

Althon Angled precast concrete headwalls allow pipework entering a watercourse at an angle to be accommodated or for an outfall to be situated on a bend in a river. Some of our Angled headwalls meet the Environment Agency’s ‘Standard rules SR2015 No 27 – Constructing an outfall pipe of 300mm diameter through a headwall into a main river’ and Exempt flood risk activities: environmental permits section FRA12 ‘Outfall pipes less than 300mm diameter through a headwall’

Rectangular Headwalls

Althon Rectangular headwall range have the wingwalls projecting at 90 degrees to the backwall and can accommodate pipe up to 750mm ID. We can cast multiple openings, elliptical, square or rectangular culvert openings into any of our outfalls. We can also cast pipe openings into the wing walls. 

Culvert Headwalls

Althon box culvert headwalls are a great alternative to in-situ inlet and outfall structures for the start and end of box culvert runs. We can factory fit flap valves, penstocks, Kee Klamp® handrails and gratings to all of our culvert headwalls range.

Splayed Wing Wall Headwalls

Althon's Splayed headwall range are precast headwalls produced with higher wing walls at the front of the apron. These headwalls can be situated in locations with high or steep embankments or where the structure is required to provide protection to an accessory such as a flap valve, duck bill valve, stop logs or weir wall. 

SFA Headwalls with Precast Steps

Althon offer precast concrete Sewers for Adoption compliant headwalls complete with precast concrete steps. Typically our precast headwalls with steps will be supplied with an appropriate Sewers for Adoption compliant outfall safety grille and galvanised steel Kee Klamp® handrailing with gated access.

Swale Inlets Headwalls

Althon swale and pond inlet mitred headwalls up to 300mm are fibre reinforced precast concrete open inlets allowing surface water runoff to enter SUDS features, or to act as an outlet or overflow. The profile of the inlet 1:3 (18 Degrees) is the same as the surrounding ground in accordance with guidelines for the construction and adoption of swales and ponds. There is a recess formed in either side to key the unit into the slope of the swale or pond and prevent it slipping.

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