Concrete frame process analyser
Every frame decision trades cost against time, carbon and cash. A post-tensioned slab, a jumpform core, a low-carbon mix, a second shift or a second crane each move all four at once.
This model makes those trade-offs visible. Change the levers and watch the estimate, programme, carbon and cash flow update, or let it search every combination for the lowest cost, the fastest build, the lowest carbon or the best balance.
Cost breakdown
Carbon
Programme - line of balance
Each trade marches up the floors at the takt beat for the current configuration. The core leads (jump/slip) or sits on the critical path (traditional).
Programme summary
Labour histogram - operatives on site by trade
Weekly headcount by trade across the frame. Peak and total person-weeks below.
Resource summary
Quantities by type
Reinforcement intensity by structural element
Slab uses the slab-system density; columns & core use their own (editable) density. Toggle the unit basis.
Concrete placement (m³/week)
Rebar fixing (t/week)
Floor-cycle velocity - what paces each floor
Days per floor up the building. Orange = labour-driven (compressible with shifts, gangs or a second hook); green = cure-driven (fixed by concrete chemistry - no resource beats it). Dashed line is the cure floor. Watch the learning curve pull the early floors down until they hit it.
Where the programme is won or lost
The binding constraint, what's on the critical path, and whether the crane can keep up - the levers that actually move the date.
Cumulative control curve
Cash-flow & net present value
Monthly valuations from the weekly cost profile, with retention withheld and released, discounted to present value. Set the financing terms below.
Monthly valuation (gross = paid + retention)
Cumulative net cash-out (nominal vs present value)
Cost sensitivity to fundamental rates - tornado
Each bar swings one rate across its low/high range while all other rates hold at the central (live) value. Longest bar = the rate your estimate is most exposed to. The KPIs show the combined low/high envelope. Ranges default to the Q2-2026 UK market spread and are editable below.
Range inputs - low / high per rate
Central is the live editable rate from the Inputs tab. Set realistic low/high bounds; the tornado and envelope update live. Labour low/high apply to all trades together.
Scenario comparison
Save the current configuration to slot A, B or C (toolbar above). The current live configuration is always shown alongside. Click a saved scenario's name to load it back into the controls.
Side-by-side - cost / time / carbon
Model inputs & assumptions editable
Every value the engine uses - commercial rates, labour man-hour productivities, and structural assumptions - is exposed here for audit and editing. Type your own rates to calibrate against a real estimate; outputs update live.
Option comparison - one click, every objective
Holds your building (floors, footprint, cores) fixed and searches all 972 method combinations for the best under each objective, alongside your current configuration. Best value in each row is highlighted. Use Print / PDF to issue.
The trade-off cloud - every combination
Each dot is one lever combination. Position = cost vs carbon; colour = programme length. Current ringed; optimum for the last objective starred.
Model assumptions (rates as at Q2 2026; editable in the Inputs & Sensitivity tabs)
What the model shows
- The fastest frame is rarely the cheapest. Extra falsework, a second hook or a second shift buys weeks, and the prelims saved may or may not pay for them. The trade-off cloud shows where that line sits for a given building.
- Carbon and speed pull against each other. High-slag mixes cut embodied carbon but gain strength more slowly, which lengthens strike times and the floor cycle.
- Cash matters as well as cost. The cash-flow view shows monthly valuations, the peak month and the net present value of cost, so two options with the same outturn can be compared on timing as well as total.
We use models like this to test frame strategy at tender and pre-construction, and to challenge a programme or estimate before it is committed. Discuss a frame strategy review →