Drainage Design for Lambeth Extension
Budget / Salary£250–750
TypeFreelance project
LocationRemote
Posted1 hour ago
I need a qualified drainage designer to produce a full foul- and surface-water strategy that Lambeth Building Control will sign off for my rear two-storey extension and new basement. Planning permission is already secured and the architectural and structural drawings are ready for you to work from; I will share the DWGs and PDFs as soon as we start.
The key driver is flood prevention. The garden sits in an area where surcharging has occurred in the past, so I want clear attenuation and back-up measures sized with real rainfall data and London guidance. Wherever practical I would like the pipework specified in PVC because that keeps the install cost down and matches most of the existing runs on site. The new system must also tie into the current foul and surface connections at the rear manhole without disrupting neighbouring properties.
What I expect from you
• A coordinated drainage layout (plan, long sections and details) showing pipe sizes, gradients, sump locations and any pump chambers for the basement.
• Hydraulic calculations and attenuation volumes that meet the current Building Regulations, London SuDS hierarchy and Lambeth’s specific requirements.
• A concise design report explaining the methodology, maintenance notes and how flood risk has been mitigated.
• Any schedules or notes that my builder can lift straight onto site.
Preferred tools are MicroDrainage (for calcs) and AutoCAD or Revit (for drawings), though I’m open if you use equivalent software that produces the same level of detail. All files should be issued in PDF and editable DWG formats.
I will review the first draft with my structural engineer; after that we should only need one revision round to address any comments from Building Control.
The front existing invert Level is 1.2 meters below ground level
The new gravity system should run through the garage situated below the proposed new kitchen and all new drainage should use this side of the house
The area of clay behind the left hand side garage will be excavated
Plans can be viewed on the Lambeth planning portal reference 00840 and the plans have been passed
Address of property
30 Ferndene Rd SE240AB.
The key driver is flood prevention. The garden sits in an area where surcharging has occurred in the past, so I want clear attenuation and back-up measures sized with real rainfall data and London guidance. Wherever practical I would like the pipework specified in PVC because that keeps the install cost down and matches most of the existing runs on site. The new system must also tie into the current foul and surface connections at the rear manhole without disrupting neighbouring properties.
What I expect from you
• A coordinated drainage layout (plan, long sections and details) showing pipe sizes, gradients, sump locations and any pump chambers for the basement.
• Hydraulic calculations and attenuation volumes that meet the current Building Regulations, London SuDS hierarchy and Lambeth’s specific requirements.
• A concise design report explaining the methodology, maintenance notes and how flood risk has been mitigated.
• Any schedules or notes that my builder can lift straight onto site.
Preferred tools are MicroDrainage (for calcs) and AutoCAD or Revit (for drawings), though I’m open if you use equivalent software that produces the same level of detail. All files should be issued in PDF and editable DWG formats.
I will review the first draft with my structural engineer; after that we should only need one revision round to address any comments from Building Control.
The front existing invert Level is 1.2 meters below ground level
The new gravity system should run through the garage situated below the proposed new kitchen and all new drainage should use this side of the house
The area of clay behind the left hand side garage will be excavated
Plans can be viewed on the Lambeth planning portal reference 00840 and the plans have been passed
Address of property
30 Ferndene Rd SE240AB.
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