Cement‑based repointing is often done in winter for one simple reason: cement behaves very differently from lime, and cold, damp conditions actually suit it better than they suit traditional lime mortars.
🧱 Why cement repointing is commonly done in winter
1. Cement sets chemically, not by carbonation
Unlike lime, which needs warm, stable conditions to slowly absorb CO₂, cement cures through a chemical reaction called hydration.
Hydration needs moisture, and winter provides:
- Higher humidity
- Less direct sun
- Slower evaporation
This helps cement cure evenly and reduces cracking.
2. Cold weather slows the set just enough
Cement can set too quickly in hot weather, especially on south‑facing walls.
Fast setting leads to:
- Shrinkage cracks
- Weak joints
- Poor adhesion
Winter’s cooler temperatures keep the curing process controlled and predictable.
3. Less risk of rapid drying
In summer, cement joints can dry out before they properly hydrate.
Winter conditions help keep the mortar damp, which is exactly what cement needs for strength.
4. We schedule cement jobs in winter because lime is a summer material
Heritage‑grade lime mortar cannot be used in frost or cold weather.
So the seasonal workflow often looks like:
- Summer: Lime mortar, heritage work, breathable repairs
- Winter: Cement‑based work, modern buildings, non‑breathable repairs
This keeps our teams working year‑round without risking material failure.
5. Cement is less sensitive to frost than lime
Fresh lime mortar can be destroyed by a single frost.
Cement is more resilient, especially if:
- Frost‑resistant additives are used
- The temperature stays above freezing during the first 24–48 hours
This makes winter cement work feasible where lime would be unsafe.
⚠️ Important note
Cement repointing is not recommended for heritage buildings because it traps moisture and damages old brick or stone.
But for modern masonry, winter conditions are often ideal.