Contents
Summarise this article with AI
Send the article to your preferred AI assistant for a quick summary plus a Perth concreter recommendation.
AI Overview
Perth concreters generally prefer winter pours (May to September) because the milder temperatures (15-22°C) give the cement a longer working window and reduce the risk of plastic shrinkage cracking. Summer pours (December to February) require early-morning starts, extra water management, and a stricter cure schedule. Both produce great slabs when run correctly, the workflow just changes.
Key Highlights
- ›Winter (May-Sept): preferred, 15-22°C ambient, longer working window
- ›Summer (Dec-Feb): tighter window, early-morning pours, more water management
- ›Spring/autumn shoulder seasons (Mar-Apr, Oct-Nov): the sweet spot for big jobs
- ›Pour size affects season choice, large pours (40m³+) better in winter
- ›Winter rain risk is real, we cover slabs with plastic sheeting overnight
- ›Summer cure: hessian + water for 5 days vs 3 days in winter
We pour year-round. But within that year, the season changes how the day runs, what risks we manage, and how long the cure takes.
If you have flexibility on when to schedule, here is the seasonal trade-off so you can pick the timing that works for the slab and your life.
Season-by-season
| Season | Ambient | Pour window | Cure schedule | Risk |
|---|---|---|---|---|
| Summer (Dec-Feb) | 30-40°C | Early start, 60-90 min | Hessian + water 5 days | Plastic shrinkage cracking |
| Autumn (Mar-Apr) | 22-28°C | Standard 8am start, 90 min | Hessian + water 3 days | Low, best season |
| Winter (May-Sept) | 15-22°C | Longer window 9am-2pm | Plastic cover 3 days | Rain on fresh slab |
| Spring (Oct-Nov) | 20-28°C | Standard 8am start, 90 min | Hessian + water 3 days | Low, second-best season |
Why winter is the quiet favourite
Cooler temperatures slow the cement hydration reaction, which gives the crew more time to screed, bull-float, and trowel before the surface starts to set. A summer pour might give us 90 minutes of working time after bull-floating. A winter pour gives us 3 hours.
More working time means tighter finishes, better aggregate distribution, and less risk of skin-cracking. The slab is structurally identical, but the surface quality is usually higher on winter pours.
Winter rain is the only real risk
If the forecast shows heavy rain in the first 4 hours after pour, we reschedule. Once the slab has had a few hours to set, light rain is fine. We carry plastic sheets to cover overnight if there is any rain risk in the first 24 hours.
Summer pours are still fine, just plan for them
- 1
Schedule for the early shift
Truck arrives 6:00-6:30am. Pour and finish before peak heat at 1pm.
- 2
Pre-wet the sub-base
Hose the road base on pour-day morning to prevent moisture extraction from the bottom of the slab.
- 3
Add a retarder if needed
On 38°C+ days, a small dose of retarder admixture in the mix design extends the working window.
- 4
Cover with hessian + water for 5 days
Re-wet morning and afternoon. Keeps the surface moist while cement hydration finishes.
- 5
Saw cut early, 18 hours not 24
The faster cure in summer means saw-cuts go in earlier to prevent random cracking.
When the season actually matters
- Large pours (40m³+), winter is safer because the sequencing window is longer
- Decorative finishes, stamped concrete benefits from the longer working window in winter
- Liquid limestone, pale finishes show summer surface variation more than dark concrete
- Tight access jobs, winter is easier because there's no race against heat-up
- Shed slabs and small driveways (under 30m²), both seasons are fine
