Formwork inspection before the pour: the hold points that stop a bad deck
A deck is only as good as the checks before the truck arrives. These are the hold points a formwork crew works through on a suspended slab, and what the head contractor should expect to see signed off.
Set-out against the survey
Before the first bearer goes down, the grid, the slab edge, the set-downs and the penetrations are checked against the survey and the architectural set. A deck set out wrong is a deck stripped and rebuilt.
Propping and bracing
Props are placed to the propping design: spacing, bearer and joist centres, and the bracing the design calls for. Back-propping to the floors below is checked against the engineer's sequence. A certifier or the formwork supervisor signs the propping off before reinforcement starts.
Edge forms, ties and penetrations
Edge shutters, step-downs and upstands are checked square and to line, ties and bracing on walls and columns are inspected, and every penetration is boxed where the services drawings say it is. Formed surfaces are checked against the AS 3610 finish class on the drawings, because a class 2 soffit and a class 4 soffit are formed differently.
Reinforcement and the engineer
Once the steel is tied, cover, laps, chairs and starter bars are checked before the engineer's inspection is called. The pour is booked against that inspection, not after it, so a first-time pass keeps the program and a failed inspection costs a pour date.
Stripping
Stripping is on cylinder results in the sequence the engineer sets, never on the calendar. Back-propping stays as the design requires while the structure rises.
Questions
What is AS 3610?
The Australian Standard for formwork for concrete. It sets the finish classes for formed surfaces and the requirements for design, erection and stripping.
Who certifies the propping?
The formwork supervisor or an independent certifier, depending on the head contractor's requirements. Either way, propping is signed off before the pour.
How does self-performing the steel and the pour change the inspection?
The deck is inspection-ready the day it is propped, and the truck is booked against the engineer's inspection because the pour crew is the same company.
Send the drawings.
Issue the for-construction set for the packages you want priced and the quotation comes back itemised, with the basis shown against every line.