Can heavy snow loads collapse a deck in northern New Brunswick?

Yes, heavy snow accumulation can and does cause deck collapses in northern New Brunswick, particularly on undersized or aging structures that were not designed for the region's substantial snow loads.

Northern New Brunswick — communities like Edmundston, Campbellton, Bathurst, and the Acadian Peninsula — receives some of the highest annual snowfall totals east of the Rockies. Edmundston averages over 300 centimetres of snowfall per season, and individual storms can drop 30 to 50 centimetres in a 24-hour period. When that snow accumulates on a deck without being cleared, the weight adds up rapidly. Fresh fluffy snow weighs roughly 50 to 70 kilograms per cubic metre, but once it settles and compacts — or worse, absorbs rain and partially melts and refreezes — that weight can increase to 200 to 400 kilograms per cubic metre. A 3-metre by 4-metre deck with 60 centimetres of settled, wet snow on it can easily be carrying over 2,500 kilograms of additional load that the structure may not have been engineered to support.

The New Brunswick Building Code specifies ground snow loads that vary by region, and northern zones carry significantly higher requirements than southern communities like Saint John or Moncton. A deck designed to code in the north will have larger joists, closer joist spacing, larger beams, and more substantial post and footing sizes than an identical-looking deck in the south. The problem is that many residential decks, particularly older ones built in the 1990s and early 2000s, were constructed without permits and without engineering, using standard dimensional lumber and spacing that would be adequate in milder climates but falls short in heavy snow territory.

The warning signs of an overloaded deck are visible if you know what to look for. Joists that are visibly sagging or bowing downward between beams indicate the lumber is being stressed beyond its capacity. Posts that are leaning or have shifted off their footing pads suggest the foundation is failing under load. Deck boards that have new gaps between them, or that feel springy and flexible underfoot, tell you the substructure is deflecting more than it should. Any of these signs in winter mean you should clear the snow immediately and have the structure assessed before using it.

The practical rule for northern New Brunswick homeowners is to shovel your deck whenever snow accumulation exceeds 30 centimetres. Do not wait for the end of a multi-day storm — clear it in stages. Use a plastic-edged shovel and push snow off the edges rather than piling it in the centre of the deck, which concentrates load on the weakest point of the span. Pay particular attention to areas where snow drifts against the house wall or piles up in corners, as these spots can accumulate two to three times the depth of open areas.

If you are building a new deck in Edmundston, Campbellton, or anywhere in the northern part of the province, ensure your builder is designing to the correct snow load zone. This typically means 2x10 or 2x12 joists at 12-inch centres rather than the 16-inch spacing common in southern builds, triple-ply beams rather than double-ply, and 6x6 posts rather than 4x4 for any height over 3 feet.

---

Find a Deck Building Contractor

New Brunswick Decks connects you with experienced contractors through the https://newbrunswickconstructionnetwork.com:

• R.e.j Construction ✓
• Duguay Construction ✓
• Hickory Dickory Decks Moncton ✓