JKH Drainage Units Ltd  JKH Drainage Units Ltd


Hampstead Avenue
IP28 &AS


01638 713795


01638 716313

Fact sheets

Company Profile

Established since 1969, J.K.H. are a leading manufacturer of steel reinforced pre-cast concrete products with applications ranging from land drainage and waterway management to building construction and civil engineering. Traditionally, J.K.H. was formed to serve the special needs of the agricultural industry. Nowadays, its product range has been expanded to meet the requirements of the leisure, housing, public service and telecommunications industries along with with the core business of drainage within agriculture, sportsfield and civil engineering. The company also specializes in the manufacture of moulded G.R.C. (Glass Reinforced Cement) products, in which field it has developed considerable expertise. J.K.H. have always been concerned to provide high quality, value for money products to their customers specifications. J.K.H. operates from a prime industrial location at Mildenhall in Suffolk, where it maintains over 9000sq.ft. of warehousing and more than 64500sq.ft. of open storage space.

All G.R.C. units provided by J.K.H. are manufactured by casting with purpose made moulds filled with a pre-mix of Portland cement, sharp sand and chopped strands of special alkali resistant glass fibre. Technical notes and specification available on request.

J.K.H. DRAINAGE UNITS LIMITED through their fully equipped engineering and drawing office departments have built up a sound reputation for the design and construction of steel moulds for concrete and G.R.C. production and can offer to produce 'one off' special items. Please send detailed specifications and drawings or telephone Mildenhall (STD 01638) 713795 or 713759 and ask for Brian Prince. 

Products and Services

Drainage Outfalls Spillway Headwall

All drainage pipes discharging into an open water course should be fitted with a suitable headwall to protect and locate the outfall pipe and minimize erosion at the discharge point. J.K.H. manufacture a range of headwalls to suit all pipe sizes up to 1800mm outside diameter. Generally pre-cast headwalls can be installed at a fraction of the cost of in-situ structures and have the advantage that during major maintenance work they can be removed and refitted.

Please click on the Headwall type for more information.

General Purpose Headwall in GRC,

Curve Back General Purpose Headwall in GRC

Kwik-Fit Headwall in GRC

Dyketector Range in GRC

Type 'X' Headwall

GRC 300 Series Headwall   (300mm pipe max)water control Headwall

300 Series Spillway Headwall  (300mm pipe max)

600 Series Spillway Headwall  (600mm twinwall pipe max, 450mm concrete pipe max)

1000 Series Spillway Headwall  (900mm pipe max)

2000 Series Spillway Headwall  (1500mm pipe max)

Water Control Headwall


Inspection Chambers

Normally installed at all changes of direction in a main drain, essential for providing rodding points in a long run of drain. For the connection of lateral drains at various depths, and for use as tumbling bays where it is required to slow the drainage water down on steeply slopedInsp Ch sites. J.K.H. manufacture a range of pre-cast chambers that will cater for all pipe sizes up to 1400mm outside diameter.

Octagonal Junction Box

Sectional Junction Box

GRC Inspection Chamber

Sectional Inspection Chamber

Big 'J' Inspection Chamber

Water Supply Units - Meter Chamber, Hydrant Chamber, Stop Cock Box Tops, Equipment Housing

Silt TrapSilt Traps

Wherever water is to be fed from an open watercourse into a pipe, a suitable silt trap inlet should be provided. The sloped gratings provided minimize the risk of blocking from floating material, and the silt chamber will collect the worst of the heavy objects and silt. It is, of course, essential that all sites where such units are required, should be regularly inspected and the accumulating rubbish and silt be removed to avoid 'over-topping' and flooding. J.K.H. manufacture a range of silt trap inlets to cater from 150mm pipe up to 1400mm.

GRC Silt Trap Inlets  (Square GRC, Curved Back GRC, and Double Entry Silt Traps)

Type-X Silt Trap Inlet

Two Piece Heavy Duty Silt Trap

Culvert End Wall, Earth Retaining Structures

W.C. Headwall (water Control Facility)

Conventional Weir  (Big 'L' Supports and Big 'L' used on a Conventional and V-notch Weir)

End Walls  (Lagoon Strainer Wall and Culvert End Wall)


Erosion Protection ChannelsErosion Protection

Dyketector Channel Range GRC

Anti Erosion Channel


Gratings and Vermin Gates 

During periods of dry weather rodents and vermin are known to use open drains for refuge and nesting purposes with the consequence that a costly drainage installation could be disrupted. There is a particular Health and Safety aspect regarding larger diameter outfalls where children and vandals could gain access and these should always be protected by suitable stout gratings. 


J.K.H. manufacture a range of gratings to cover all sizes of pipes. manufactured in mild steel, hot dip galvanized and provided with suitable brackets for mounting directly to the headwall structure. Special gratings made to customers specifications can be manufactured in mild steel or stainless steel on request.
Custom Gratings, Standard Grating, Sloped Grating or Cranked Grating
Vermin Gates

For internal pipe sizes of: 60mm, 80mm, 100mm, 150mm 225mm and 300mm.

Stainless steel hinged gratings for attaching directly to the pipe. So arranged to prevent entry of small animals but able to open outwards to prevent any blockage from debris coming down the pipe. Easily fitted with single stainless steel nut and bolt. Suitable for all types of pipe. Detailed instructions issued with each order.