Temporary Works calculators
11 temporary works calculators: scaffold quantities, birdcage scaffold, formwork turnover, lateral pressure, ties, sheet pile walls, tower crane base check, roof falls, insulation and drainage.
What this group solves
Temporary works are the category that surprises people: formwork, scaffolding and shoring never appear on the drawings, yet they carry a large share of cost and programme, and they are measured by completely different rules — formwork by contact area, scaffold by elevation or enclosed volume, and reusable material by turnover count.
What these tools share is heavy parameterisation and hard code limits. Stud spacing, lift height and tie arrangement all have upper bounds; formwork pressure varies with pour rate, temperature and slump and directly sets the tie spacing; sheet pile embedment needs overturning and heave checks; crane bases need bearing and stability checks. The outputs here are quantities and preliminary checks — anything affecting safety needs a sealed design from a qualified engineer.
Preliminaries are the easiest section to under-price in a tender: scaffolding, formwork and crane bases are not permanent work, yet every one has mandatory detailing — spacing, wall ties, reinforcement, bearing capacity. Under-count and you either lose it at audit or rebuild it on site. These quantities are rarely on the drawings; they come out of the specification and the method statement. Fix the system first, then the quantity, then turnover and amortisation.
Which one for your case
| External scaffold area plus tube and coupler counts | Scaffolding Calculator |
| How many formwork sets and how many reuses | Formwork Turnover Calculator |
| Falsework post spacing and lift height | Full Scaffold Material Calculator |
| Lateral pressure of fresh concrete on formwork | Formwork Lateral Pressure Calculator |
| Wall tie layout — lifts by bays | Scaffold Tie Calculator |
| Tower crane base size and reinforcement | Tower Crane Foundation Check |
| Sheet pile embedment depth for a deep excavation | Steel Sheet Pile Calculator |
| Roof downpipe count and gutter section | Roof Drainage Calculator |
| Mean thickness of a roof slope layer | Roof Slope Layer Calculator |
Where this group goes wrong
- Deriving scaffold from floor area. External scaffold is the vertical projection of the outer face (length × height), with openings and balconies not deducted; height runs from existing ground to the eaves (to the top of the parapet where there is one), not storey height times storeys. With a basement, measure from the basement roof slab.
- Using 1.2 m post spacing for falsework as a default. Spacing follows load: slabs over 200 mm thick or heavy beam loads need 0.9 m or even 0.75 m, with the lift reduced from 1.5 m to 1.2 m, or the post stability check will not pass.
- Building the crane base to the manual's minimum size without checking bearing capacity. Those dimensions assume a characteristic bearing capacity of at least 200 kPa; backfill or soft clay gives 80-120 kPa and needs a base enlarged by 1.5 times or more — otherwise it tilts.
- Ordering the roof slope layer at its thinnest point. Mean thickness = minimum + span × slope / 2, so a 10 m span at 2% is 100 mm thicker on average than the minimum — using the minimum halves the material.