Plumbing & Heating: Steps to Handover
Golden sequence (builders × installers)
Demolition → Layout & mark-ups → Chasing/floor cuts/ceiling framing → First-fix pipes & manifolds → Pressure tests → Close chases/render/screeds → Waterproofing (wet rooms) → Tiling/finishes → Second-fix (radiators, sanitaryware, boiler/heat pump) → Commissioning → Final sealants & handover.
Reordering these steps causes leaks behind finishes, noise, and costly rework.
Step-by-step
1) Design, layout & set-outs
- Room-by-room point schedule (WC, basins, showers, kitchen sink, DW/WM, water heater, radiators/UFH loops).
- Pipework strategy: hot/cold in PEX/MLCP/copper; drainage (PVC/PP) with correct falls (e.g., 1–2%).
- Heating strategy: radiators with TRVs, and/or underfloor heating (UFH) with zones and a central manifold.
- Appliance specs locked (boiler/heat pump, cylinders, mixing valves, pumps, expansion vessels).
2) Chasing & structural coordination
- Cut vertical/horizontal chases only; respect depth limits.
- Core drill penetrations (stacks, vents, AC condensate) with sleeves and fire collars where required.
- Mark finished floor heights (FFH) and shower bases for correct outlet heights.
3) First-fix water & heating
- Cold/Hot feeds: run from riser/plant to points; clip & insulate (hot and chilled lines).
- Heating manifolds: mount radiator/UFH manifold in accessible cabinets; label loops; run PEX to each emitter (radiator or UFH circuit).
- Radiator preps: install wall plates/brackets and isolation valves; leave tails capped.
- UFH (if any): fix pipes to insulation/mesh per layout; pressure test before screed.
- Drainage: route wastes with continuous fall; avoid back-to-back fixture conflicts; add cleanouts.
- Vents/air admittance per code; plan condensate lines (boiler/AC) with fall and tundish where needed.
4) Testing (HOLD POINT 1)
- Cold/Hot pressure tests (e.g., 6–10 bar water or per local code) for the full network including UFH.
- Drain down & re-pressurize after 30–60 minutes to confirm stability.
- Record results with photos of concealed routes and capped points.
5) Close-up & wet-area prep
- Builders close chases, render/board; protect pipe exits.
- Screeds poured (embedding UFH where applicable); observe cure.
- Waterproofing in wet rooms (primer + tapes + 2 coats) after substrates are ready; 24-hour flood test before tiling.
6) Second-fix heating & plant
- Boiler / Heat Pump / Water Heater: mount with clearances; flue/condensate connected; gas tightness test (for gas).
- Pumps, valves, filters, expansion vessels, mixing valves installed at plant and manifolds.
- Radiators: hang, connect to tails, fit TRVs and lockshields; bleed caps ready.
- UFH: actuators on manifold; wire to room thermostats; verify zone labels.
7) Second-fix sanitaryware
- WC frames set and pressure-tested; pans/bidets fixed and sealed.
- Basins/baths/showers connected with accessible isolation valves; traps tested; linear drains set to height and slope.
- Kitchen/utility: sink, DW/WM valves, filters/softeners (if specified), grease-friendly trap.
8) Flushing, cleaning & balancing (HOLD POINT 2)
- Flush heating loops; add inhibitor; bleed/vent all emitters.
- Hydronic balancing: set lockshields; verify ΔT across radiators; set UFH flow meters per room design.
- Domestic hot water (DHW): run to temp; verify recirculation (if present) and check anti-scald TMVs.
9) Controls & commissioning
- Power up boiler/HP controls, thermostats, and actuators; set schedules.
- Verify safety devices (PRVs, expansion vessel charge, condensate route).
- Record temperatures, pressures, pump speeds, and serials; leave controller access with the client.
10) Final finishes & handover
- Sanitary silicone (after full dry), caulk neat lines; polish chrome/ware.
- Deliver as-builts, valve map, balancing sheet, warranty cards, and a simple user guide (bleeding, seasonal settings, filter cleaning).
Coordination with other trades (save rework)
- Electricians: power & controls to boiler/HP, manifold actuators, pumps, mirror demist/fans.
- Drywallers/tilers: exact heights/centres for mixers, spouts, shower niches, linear drains.
- Joinery/Kitchen: sink/disposal/DW/WM locations, worktop cut-outs, panel access to traps/valves.
- HVAC: condensate lines; fan positions and duct routes to exterior.
Quality checkpoints (don’t skip)
- Pressure tests before any wall close-up or screed.
- UFH pressured and monitored during screed pour.
- Wet-room flood test before tiling.
- Plant room leak-free 24 h observation after first heat-up.
- Combustion analysis (gas boiler) and gas tightness certificate (where applicable).
Common mistakes & fixes
- Hidden leaks due to skipped tests → Always test & photograph first.
- Wrong shower falls/linear drain height → Set pre-slope at screed; dry-fit drain before waterproofing.
- No isolation valves at fixtures → Fit for every outlet; future service is faster.
- Mixed metals without isolation → Use dielectric fittings to prevent galvanic corrosion.
- No access to traps/valves → Include panels in vanity/boxing; agree locations with client.
- No balancing → Uneven heating; always balance radiators/UFH and log values.
Programme & cost (percentages only; baseline = disciplined first-fix + second-fix without UFH = 0%)
- Add UFH (manifold + loops + controls): +25–50% vs baseline; comfort/efficiency gains significant.
- Add recirculation line for DHW: +5–15% vs baseline; hot water wait times −50–90%.
- Premium brassware/frames & linear drains: +10–35% vs baseline; maintenance −5–15% (better parts).
- Skipping hold-point tests (risk): downstream rework +20–60% vs baseline if a leak appears post-tile.
- Pre-fab manifolds/press-fit systems: +5–15% materials, −10–25% labour time and leaks.
Quick checklists (print-ready)
First Fix
- ☐ Points schedule approved; heights marked
- ☐ Chases/cores done; sleeves & fire collars in place
- ☐ Manifolds fixed, labelled; pipes clipped & insulated
- ☐ Drainage with correct falls and cleanouts
- ☐ Pressure tests passed & photographed
Before Finishes
- ☐ Screeds cured; moisture acceptable
- ☐ Waterproofing done; 24 h flood test passed
- ☐ Tile set-outs agreed (centres, niches, trims)
Second Fix & Commissioning
- ☐ Radiators hung, TRVs fitted; UFH actuators wired
- ☐ Boiler/HP started; flue/condensate verified
- ☐ System flushed, inhibitor added; all loops balanced
- ☐ DHW temp & TMVs verified; no drips after 24 h
- ☐ Handover pack delivered (as-builts, valve map, warranties, service schedule)
Spec tips (hot climates incl. Dubai)
- Prioritise quiet pumps, insulated hot lines, and balanced DHW for quick hot water.
- Consider heat pump + UFH/FCU combos for efficient cooling/heating; ensure correct condensate handling.
- Use scale control (softener/conditioner) where water hardness is high to extend fixture life.
