How long should concrete footings cure before building a deck in NB?

Concrete footings need a minimum of 7 days before you load them with framing, but waiting the full 28 days gives you full strength — and in New Brunswick's climate, patience here pays off significantly.

Concrete gains strength progressively after pouring. It reaches roughly 70% of its design strength at 7 days, which is generally considered the safe minimum before placing posts and beginning framing. However, full cure to 100% strength takes 28 days. For a deck that needs to handle NB's snow loads (2.0–3.5 kPa depending on your region) plus decades of freeze-thaw cycles, letting footings cure as long as your schedule allows is genuinely worth it.

Temperature is the critical variable in New Brunswick. Concrete needs sustained temperatures above 10°C to cure properly — below that, the hydration process slows dramatically, and below freezing it stops entirely and can be permanently damaged. This is why footing season in NB runs from late May through September. If you pour in early May or late October when nights are still dipping near freezing, you'll need to use insulating blankets or heated enclosures to protect the fresh concrete. Most experienced NB contractors simply avoid pouring outside that window rather than risk a compromised footing.

Humidity actually works in your favour here. Unlike the dry Prairie climate where concrete can dry out too fast, New Brunswick's Maritime humidity helps keep concrete moist during curing, which is exactly what you want. Covering fresh footings with burlap or plastic sheeting for the first week helps retain that moisture and improves the cure — a simple step that makes a real difference.

Practical Steps Before You Build

Keep the footing tops covered and protected for at least the first 48–72 hours. Mark your pour date and resist the urge to start framing before day 7, even if the concrete feels rock-hard to the touch — surface hardness is misleading. If your schedule allows, aim for that 28-day mark before putting any significant load on the footings.

Also remember that NB frost depths range from 1.2 metres in the Moncton/Saint John/Fredericton area up to 1.5 metres in Bathurst, Campbellton, and Edmundston. A perfectly cured footing that doesn't reach below frost depth will still heave — so depth matters just as much as cure time.

This is firmly in professional territory. Footing sizing, depth, and placement are structural and code-regulated — any deck attached to your house or more than 600mm above grade requires a permit and footing inspection in NB. A building inspector will actually check your footing depth before you pour, which is a good thing. If you're planning a project for this summer, now is a great time to get matched with a local builder. New Brunswick Decks can connect you with a deck contractor in your area for a free estimate — just reach out and we'll do the matching for free.