Drainage installation
New drain runs, soakaways
and mains connections —
specified and certified
Full drainage installation across Kent — extensions, new builds, outbuildings and soakaways. Falls calculated properly, materials specified correctly, building control sign-off handled.
What it covers
New drainage runs done to spec — falls correct, materials right, sign-off in your file
Installing drainage is the part of a building project that nobody sees once it's finished, and that's exactly why it gets cut. Falls are eyeballed, joints are kicked together, inspection chambers are skipped, and the bill arrives two years later when a kitchen extension floods because the drain runs uphill in two places.
Our drainage installation work covers new connections for extensions and outbuildings, drainage for kitchen and bathroom additions, foul water and surface water separation, new soakaways and rainwater management, mains drain connections to public sewer, and full new build site drainage.
Every install is set out with laser levels, bedded properly in pea shingle or sand to manufacturer spec, jointed with the correct rubber rings and lubricant, inspected with intermediate chambers at the right intervals, and tested before backfill. Building control sign-off is handled where required.
What happens if you wait
A drain installed badly is a drain you'll pay to replace before the building is sold
Pipe runs with insufficient fall silt up. Joints kicked together with no lubricant leak. Soakaways sized to optimism flood gardens. Missing inspection chambers mean future blockages can't be located. Every one of these is a known failure mode and every one is preventable with proper installation.
Insufficient fall, badly jointed pipework and missing rodding access turn into chronic blockages straight after handover.
Drainage that doesn't meet Building Regs Part H delays sign-off and can hold up a sale or completion certificate.
Leaking new drainage and undersized soakaways contribute to subsidence and surface flooding within a few seasons.
Common mistakes we fix every week
- Setting falls by eye instead of by laser level.
- Kicking pipe joints together without lubricant — guaranteed slow leak.
- Skipping intermediate inspection chambers on longer runs.
- Sizing a soakaway to the contractor's quickest answer rather than soil percolation tests.
- Connecting surface water into foul drainage where separate systems exist.
- Backfilling before testing the install.
Our process
A predictable, step-by-step system — no surprises, no upsells
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STEP 01Survey & design
Site survey, falls calculated, materials specified, soakaway sized where applicable.
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STEP 02Building control liaison
Drawings and notifications submitted, BC site inspection coordinated where required.
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STEP 03Excavate & install
Trenches dug to spec, bedding laid, pipework jointed properly, chambers set.
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STEP 04Test before backfill
Air test or water test on every run — failures rectified before any backfill goes in.
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STEP 05Sign-off & handover
Building control sign-off, as-built drawings, photographs and workmanship guarantee in writing.
What you get
Concrete outcomes — not vague promises
Laser-level set falls on every run — no eyeballed slopes, no silting-up later.
uPVC, clay or polypropylene specified per location, depth and load — never substituted to save a tenner.
Notifications, inspections and sign-off coordinated — paperwork on completion.
Every install tested for water-tightness before any soil goes back in the trench.
Pea shingle or sand bedding to manufacturer spec — pipes supported along their entire length.
Workmanship guarantee on every install, plus as-built drawings for your records.
Technical detail
What goes into a properly installed drainage run
Modern drainage installation is governed by Building Regulations Part H, BS EN 752 and manufacturer technical guidance. The rules aren't arbitrary — every one of them exists because somebody got it wrong on enough sites to make it worth writing down.
Falls and gradients
Foul water drains are typically laid at 1:40 for 100mm pipe and 1:80 for 150mm. Surface water is more forgiving but still needs a deliberate fall. We set every fall with a laser level — there is no situation in which a 'good enough by eye' fall is acceptable on a buried drain.
Bedding and surround
Pipes need to be supported along their entire length on suitable bedding — typically 100mm of pea shingle or sand below the pipe and a haunching of the same material around it. Backfilling onto rough ground with broken hardcore is how you crush a pipe within months of installation.
- 100mm bedding below the pipe
- Haunching around the pipe to the springing line
- 150mm of selected material as surround
- Compacted backfill in 200mm layers above
Inspection chambers and rodding eyes
Inspection chambers are required at junctions, changes of direction, changes of gradient and at maximum 22m intervals on straight runs. Skipping them saves a contractor a few hundred pounds on day one and costs the building owner thousands the first time a blockage needs locating.
Testing before backfill
Every drainage installation must be tested for water-tightness before backfill — air test or water test depending on the system. Failures are rectified at the joint or section where they're found, not blamed on the test. The test result is documented as part of the handover pack.
Frequently asked
Straight answers to the questions Kent homeowners ask us most
Do I need building control for new drainage?+
For most extensions, new builds and new sewer connections, yes. We handle the notifications and site inspections as part of the install.
What does a typical drainage installation cost?+
Costs vary widely with depth, length and material — a typical extension drainage tie-in is a few thousand pounds; a new soakaway is a similar order; full site drainage is quoted per project after a site survey.
Can you connect to the public sewer?+
Yes — we handle S106 connection applications with the water authority and carry out the connection to the appropriate standard.
What pipe material do you use?+
uPVC for most domestic and shallow commercial runs, clay where loading and depth require it, and polypropylene for high-temperature commercial applications. Spec'd per project.
Can you do a soakaway?+
Yes — soakaways are sized from soil percolation tests and the rainfall area they serve. We size and install to BRE Digest 365.
Will you provide as-built drawings?+
Yes — every install ends with a marked-up drawing showing pipe routes, chamber positions, depths and invert levels. The drawing is kept with the project handover pack.
What guarantee do you offer?+
Workmanship is guaranteed for up to 5 years from the date of installation, with pipe materials carrying their own manufacturer warranties.
What areas do you cover for installation work?+
Kent and the South East. Larger projects are priced per site after survey.
Related services
Areas we cover
Get the drainage installed properly — once, signed off, done.
Free site survey across Kent. Fixed price in writing. Building control sign-off and as-built drawings included.
Fully insured · Workmanship guarantee · 7 days a week