Every experienced site agent has watched a pour go wrong, and almost none of those failures started on the day. They started with a decision made a week earlier that nobody revisited. Here is the sequence worth walking before you book the trucks.
Sign the formwork off the day before, not on the morning
Formwork problems are the single most common reason a pour stops. Props at the wrong spacing, a soffit out of level, a wall form not properly tied — all of them are fixable the day before and expensive on the day.
Walk the deck with the foreman the previous afternoon and check:
- Prop spacing and bracing against the design, not against habit
- Levels taken and recorded, not eyeballed
- Joints sealed, so grout does not escape and leave honeycombing
- Release agent applied and the deck clean of debris and tie wire
- Edge forms and stop ends fixed, including where you intend to stop
Decide where the pour will stop before it starts
Every pour needs a planned construction joint at a location the engineer has agreed, placed where the structure can take it. If you decide at 6pm, in the dark, that you are stopping mid-span because the trucks ran out, you have created a defect that will be argued about for months.
Check the steel against the drawing, then check the cover
Reinforcement is signed off before the pour or it is not signed off at all. Bar sizes, spacing, laps and — most often missed — cover. Spacers get knocked out of position during fixing and by anyone walking the deck. Cover that is short is a durability problem you will not see for years and cannot correct afterwards.
Take photographs of the fixed steel before the pour. They cost nothing and they settle arguments.
Work out your placing rate honestly
Truck spacing follows placing rate, and most delays come from optimism here. Count what you actually have: how many vibrators, how many working, how many trained operators, one pump or two, what the access is like.
Volume divided by realistic hourly rate gives you hours. Hours plus a start time tells you whether you finish in daylight. If the arithmetic says you do not, you have three options — start earlier, add resource, or reduce the pour and plan a joint. Discovering this at 4pm is not one of the options.
Look at access as the trucks will find it
A mixer is heavy, long and unforgiving. Walk the route in: gate width, turning circle, overhead cables, the state of the haul road after rain, and where a truck waits without blocking the one behind it. On a tight urban site in Kampala, agree the standing arrangement with whoever controls the road before the day, not with a traffic officer at 8am.
Plan for the weather you might get
Rain during a pour is a quality problem, not just an inconvenience: it changes the water-cement ratio at the surface and ruins the finish. Have the covers on site before you need them, not in the store across town.
Heat matters too. In strong sun, exposed concrete loses water fast and cracks plastically. Curing arrangements — covers, sheeting, water — belong in the plan alongside the trucks.
Agree the tests before the first load
Slump tests on arrival, cubes taken at the frequency the specification requires, clearly marked and stored where they will not be knocked. Decide who takes them and who signs. A load that fails slump gets sent back, and everyone should know that in advance so it happens without an argument.
The night before, in writing
The pour plan does not need to be long. One page, issued the evening before, covering:
- Volume, mix and the supplier's confirmed dispatch times
- Start time and expected finish, with the placing rate it assumes
- Crew, by name and role, including who is vibrating
- The agreed construction joint location
- Curing method and who is responsible for it
- Who stops the pour, and on what grounds
That last line is the one people leave out. When something is wrong at truck seven, the crew needs to know without asking who has the authority to stop, and that stopping is a legitimate decision rather than a failure.
After the pour
Curing is not the tidy-up, it is the last structural operation. Concrete that dries too fast does not reach its design strength no matter what the cube results say about the mix. Keep it covered and damp for the period the specification requires, and record what you did — that record is what protects you if strengths are ever questioned.
