Precast Concrete Monolithic Manhole Quantity Calculator
Fully monolithic precast concrete manhole with factory-cast base, benching, and channel as a single unit, to BS 5911-3 with BS EN 124 frame and cover. Computes excavation, monolithic base, chamber rings, reducing slab, cover slab, granular surround, and step irons.
Slug · manhole_precast · v1.0
Paid tier
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Paid assemblies surface their parameter forms, BoQ output, project save/reload, and full per-standard Excel + DXF + PDF deliverables once a CivilQuants subscription or 7-day pass is active. Per-standard bills across CESMM4, NRM2, SMM7, and MMHW; project-level recompute; watermark-free outputs.
Precast Concrete Monolithic Manhole — a worked example, measured four ways
The same assembly at default dimensions, rendered as a Bill of Quantities under each measurement standard. Switch the standard to see how the bill changes. Change the inputs in the calculator to compute your own.
CESMM4 · 15 items · units sum, nr, m³, m²
| Code | Description | Unit | Quantity |
|---|---|---|---|
| A.4.1 | Provisional sum (Prime Cost): Frame & cover, D400 loading, 600mm clear opening, with 150mm adjustment rings | sum | 1 |
| A.4.1.fix | Fixing only: Frame & cover, D400 loading, 600mm clear opening, with 150mm adjustment rings | nr | 1 |
| E.4.3.5 | Excavation for foundations, maximum depth 2-5m | m³ | 88.53 |
| E.5.3 | Disposal of excavated material off-site | m³ | 7.77 |
| E.6.3.2 | Filling, imported selected granular material, Class 6N to SHW | m³ | 0.46 |
| E.6.2.1 | Filling, excavated material | m³ | 80.77 |
| E.6.5.1 | Filling, imported sub-base, Class 6N per SHW 601 Table 6/1 row 6N | m³ | 0.52 |
| L.5.2 | Granular surround to pipe, 20mm single-size aggregate | m³ | 2.3 |
| K.1.2.3 | Precast concrete monolithic manhole base unit to BS 5911-3, 1500mm internal diameter, depth to invert 3.5m, with integral benching and pre-formed channel | nr | 1 |
| K.1.3.1 | Precast concrete chamber ring to BS 5911-3, 1500mm internal diameter, 500mm depth | nr | 3 |
| K.1.4.1 | Precast concrete reducing slab to BS 5911-3, 1500mm chamber to 675mm shaft | nr | 1 |
| K.1.3.2 | Precast concrete access shaft ring to BS 5911-3, 675mm internal diameter | nr | 2 |
| K.1.5.1 | Precast concrete cover slab to BS 5911-3, 975mm outer diameter, 600mm clear opening | nr | 1 |
| K.8.1 | Galvanised step irons cast into precast rings, 300mm centres | nr | 10 |
| E.7.2 | Geotextile filter, 200 g/m², including laps | m² | 18.14 |
Procurement take-off: the total quantity to order of each material, from the same compute. Supplier-neutral, so you buy anywhere.
- Disposal7.77 m³
- Excavation Foundation88.53 m³
- Fill General80.77 m³
- Fill Selected0.46 m³
- Fill Sub Base0.52 m³
- Geotextile Filter18.14 m²
- Manhole19 nr
- Manhole1 sum
- Pipe Surround2.3 m³
Illustrative example at default dimensions · engine ref 97e94e · not a tendered quantity