Roof Snow Load Troubleshooting: Sagging Ridges, Sticking Doors, and When to Call an Engineer

Jump to what you need

Signs of Snow Load Stress

• Sagging ridge line that was straight last fall, especially after a heavy, wet pack or a drift against a higher wall.
• Doors and windows that suddenly stick — the opening racked. Interior doors that never bound in August and bind in February are a frame-distortion tell.
• New cracking at drywall corners, ceiling/wall joints, and over headers, appearing during or right after the snow, not a year later from humidity.
• Popping, creaking, or a visible belly in a rafter bay or a porch beam under a roofed deck.
• Truss plates pulling or split webs — stop, leave the house if it is progressing, call an engineer. That is not a rake job.

Ice-dam leaks at the eave (ceiling stains just inside the wall) are water, not necessarily overload. Different tool: ice & water shield coverage calculator.

When It Is Normal Roof Creep

Wood roofs take a little permanent set. An even, long-standing sag that has looked the same for years, with no new cracks and no seasonal change in door fit, is often creep plus original camber — not this week’s snow. A ridge that dropped an inch after one storm is not creep. A porch beam that was cambered up and now sits flat under a 50 psf pack is a load check, not a paint problem.

Covered decks are where the 40 psf IRC cell and real snow part ways. If that deck is under a roof, run p_g through the snow calculator, then look at whether Table R507.5(1) in the beam tool was even the right table (snow-country rows are R507.5(2)–(4)).

When to Get a Structural Assessment

1. Any progressive movement while snow is on the roof. Get people out from under it. Rake from the ground at the eave if you can do it without standing under a belly.
2. Doors that racked this winter and did not un-stick after melt. The frame moved. That is an engineer, not a plane on the door.
3. A roof that was never designed for the mapped p_g — additions, converted attics, solar + snow, a new drift from a taller neighbor. The calculator’s balanced number is the start of that conversation, not the end.
4. Do not treat a rake as a structural fix. Taking snow off reduces demand. It does not certify the rafters.

FAQ