Sagging drywall — particularly on ceilings — is a problem Calgary homeowners run into more often than they expect. Some causes are minor installation issues; others are signs of moisture damage that needs to be addressed before any repair begins. Here's how to diagnose what you're dealing with and what to do about it.

Common Causes of Sagging Drywall

Cause 1 — Too Few Fasteners During Installation

Drywall installed with insufficient fasteners will sag over time, particularly on ceilings where gravity works against the board continuously. The minimum fastener spacing on ceilings is every 7 inches along the framing. If it was installed at 12 inches or greater — which happens on rushed jobs — the board will begin to separate from the framing, especially on longer spans. This is a fixable problem: additional screws driven into framing followed by compound over the repairs can address minor sagging if the board isn't already compromised.

Cause 2 — Wrong Board Thickness for the Span

Standard ½" drywall is rated for ceiling joist spacing of up to 16 inches on centre. On 24-inch spacing — which is common in newer Calgary construction for cost savings — ½" board will sag between framing members over time. 5⁄8" board is required on 24-inch spans. If your ceiling was installed with ½" board on 24-inch spacing, sagging is a predictable outcome, not a defect in the material itself.

Cause 3 — Moisture Damage

Water softens drywall's gypsum core. Once wet, drywall loses structural rigidity and will sag under its own weight, even on ceilings with adequate fasteners. In Calgary, moisture-related sagging often traces to: roof leaks, plumbing drips above the ceiling, bathroom exhaust fans venting into the ceiling cavity, or in basements, moisture migration from above. Moisture-related sagging is never just a drywall problem — the moisture source must be found and resolved before the repair begins, or the new board will fail the same way.

Cause 4 — Textured Ceiling Products Adding Weight

Popcorn and stipple ceiling textures add significant weight to a ceiling. On ceilings that were installed with marginal fastener patterns or lighter-gauge board, the additional weight of the texture can be enough to cause sagging that wasn't immediately apparent after installation. This is especially common in older Calgary homes with original popcorn ceilings that have never been removed or re-done.

Cause 5 — Framing Issues

In older Calgary homes, roof framing that has shifted, settled, or experienced any structural movement can cause drywall below it to sag or crack as the framing changes shape. This type of sagging is accompanied by other signs of movement — doors and windows that stick or don't close properly, and cracks at structural corners. If this is the case, the framing issue needs to be assessed before drywall repair.

Sagging drywall due to moisture always requires a moisture check before any repair board goes up. Calgary Drywall Doctor identifies the cause before quoting the fix. Written scope, moisture check included on every repair job.

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When to Repair vs. Replace

Minor sagging due to fastener failure where the board is structurally intact: repair with additional fasteners and compound work. Sagging due to moisture damage where the gypsum core has softened or the paper facing has separated: replace the affected sections. Sagging over a large area or combined with visible mold: full section replacement after the moisture source is resolved.

The key test is whether the board is still structurally sound. Press gently on the sagging area — if it feels soft, crumbly, or gives way easily, it needs replacement, not repair. For a broader view of what moisture does to drywall, see our article on moisture damage and prevention in Calgary homes. For the repair process itself, our Calgary drywall repair page explains how we approach each job.

Common Questions

Why is my ceiling drywall sagging in Calgary?

The most common causes are: too few fasteners, ½" board on 24" framing spacing (should be 5/8"), moisture damage softening the core, or texture weight on a marginally installed ceiling. Moisture-related sagging needs the source identified before any repair.

Can I fix sagging drywall myself?

Minor fastener-related sagging on intact board can sometimes be addressed by adding screws and re-finishing. Sagging from moisture damage requires professional assessment — patching over softened board without addressing the moisture source leads to repeat failure.

How much does it cost to repair sagging drywall in Calgary?

Small fastener-related repairs typically run $150–$400. Moisture-related sagging with remediation required will cost more depending on the extent of damage and whether framing is affected. Calgary Drywall Doctor provides written quotes after a site assessment.