How long after pouring should I seal concrete in New Brunswick?

In New Brunswick, you should wait a minimum of 28 days after pouring before applying a penetrating sealer — and for new concrete that will face its first winter, timing the sealing to happen in that 28-day-to-first-freeze window is critical. Sealing too early traps moisture inside the concrete before curing is complete; sealing too late leaves the fresh surface exposed to freeze-thaw cycles and salt without protection.

The 28-day rule exists for good reason. Concrete cures through hydration — a chemical reaction between cement and water that takes time. At 7 days, concrete has reached roughly 70% of its design strength. At 28 days, it has reached approximately 90%. During this period, the concrete is still releasing moisture from within. If you apply a sealer before the concrete is sufficiently dry and cured, the trapped moisture can cause the sealer to peel, blush, or fail to bond properly — wasting the cost of the sealer and leaving the surface unprotected.

Timing relative to NB seasons is equally important. If your concrete was poured in August, you have a comfortable window: pour in August, seal in late September — giving you 28+ days and still well ahead of frost season. If you poured in early October, you're working with a tighter timeline. In southern NB (Moncton, Fredericton, Saint John), the first consistent killing frosts typically arrive in late October to early November, giving you a narrow but workable window. In northern NB (Bathurst, Miramichi), that window may close earlier.

Sealer application requires temperatures above 5-10°C for the product to penetrate and cure properly. Most penetrating sealers have a minimum application temperature of 5°C and need 24-48 hours without rain. If you're applying in October, watch the forecast carefully.

For existing concrete, the timing is more flexible — you can seal in spring or fall whenever temperatures cooperate. Fall sealing before the winter freeze-thaw season begins is ideal for NB driveways and patios. Spring sealing after a thorough cleaning is a close second.

For new concrete, choose a silane/siloxane penetrating sealer rather than an acrylic or film-forming sealer. Penetrating sealers work within the concrete matrix and won't peel or flake in freeze-thaw conditions. Acrylic sealers applied to fresh concrete can trap moisture and are prone to surface failure in NB winters — they require annual reapplication and aren't well-suited to high-traffic exterior surfaces in the Maritime climate.

Sealing a new NB driveway or patio is not optional — it is the difference between a surface that lasts 30 years and one that begins showing wear within 5-7 years. Get matched with a local concrete professional through New Brunswick Concrete if you'd like help choosing the right product or having the sealing done professionally.