Winter building

Concreting below zero

Allowed with antifreeze admixtures (to −15°C per label) or heating (enclosure, thermal mats, electric heating). Without them — prohibited below +5°C.

Antifreeze admixtures

Chloride (cheap, but not for reinforced — corrosion) and chloride-free. Dose 2–5% cement mass. Admixtured concrete still needs covering for the first day.

Winter masonry

Down to −5°C possible with mortar admixtures and warmed materials; blocks can't be laid frozen/icy. Mix mortar warm, use within 1–2h.

What not to do in winter

Plastering and facade works without enclosure, torch-applied waterproofing in deep frost, pouring foundation on frozen ground, laying pavers.

Concrete curing

Critical first 3 days: concrete must reach ≥30–50% strength before freezing. Enclosure/insulated formwork, temperature monitoring inside the pour.

Cost reckoning

Winter surcharges: admixtures ~5–10% of concrete cost, enclosure+heating — rental+fuel, slower pace. Often cheaper to postpone concreting to spring.