What's the cost of fixing a leaking shower pan in a Calgary home?

Fixing a leaking shower pan in a Calgary home typically costs between $2,500 and $7,000, depending on the extent of the damage, the size of the shower, and whether the repair requires a complete tearout and rebuild or a more targeted fix. Unfortunately, most shower pan leaks cannot be patched — the underlying waterproofing failure usually requires removing the tile, addressing the membrane, and reinstalling.

A leaking shower pan means water is penetrating through or around the waterproofing layer beneath your shower floor tile and reaching the subfloor, adjacent walls, or the ceiling below (in multi-storey homes). The most common causes are failed or missing waterproofing membrane, cracked grout or caulk joints at the floor-to-wall transition, improper drain flange connection, or insufficient slope that allows water to pool rather than drain. In Calgary homes, chinook-driven temperature cycling accelerates the deterioration of grout and caulk joints, making shower pan failures more common than in cities with stable climates.

The cost breaks down based on the scope of work required. A targeted repair — where the leak is isolated to the drain flange connection or a specific area of failed membrane — may run $1,500 to $3,000 if the contractor can access and repair the problem area without a complete tearout. However, this is the exception rather than the rule. Most shower pan leaks require a full tearout and rebuild, which involves removing all shower floor tile and often wall tile up to several courses, removing the old waterproofing membrane and cement backer board, inspecting the subfloor for water damage and rot (and repairing if needed at $500 to $2,000 additional), installing new cement backer board or Kerdi Board, applying a new waterproofing membrane system, setting a proper pre-slope and shower pan with correct drainage slope of 1/4 inch per foot, and reinstalling tile with new grout and caulk.

A complete shower pan rebuild for a standard 3-by-4-foot shower in Calgary runs $3,500 to $6,000 including demolition and disposal ($500 to $1,000), new backer board and waterproofing membrane ($500 to $1,500 depending on system), new tile supply and installation ($1,500 to $3,000), plumbing work on the drain connection ($200 to $500), and new caulk and grout throughout. If the leak has caused structural damage to the subfloor or floor joists — which is common when leaks go undetected for months or years — repair costs can add $1,000 to $3,000 for subfloor replacement and joist sistering. Mould remediation, if mould is discovered behind walls or beneath the shower, adds another $500 to $2,500 depending on the extent.

If your shower pan repair involves modifying or replacing the drain connection, a plumbing permit from the City of Calgary may be required, costing $75 to $350. A Safety Codes Officer will inspect the plumbing work to verify code compliance. Even for like-for-like drain reconnection, confirm with your contractor whether a permit is needed — the rules depend on the specific scope of work.

Calgary's hard water is worth considering during a shower pan rebuild. Hard water mineral deposits can build up inside drain assemblies and weep holes, contributing to slow drainage and water pooling. When rebuilding, install a high-quality drain assembly with accessible clean-out features. Choose flexible grout and premium silicone caulk rated for extreme temperatures to withstand chinook cycling and extend the life of your new shower pan.

A leaking shower pan is never a DIY repair. The waterproofing, slope, and drain connection must be done by an experienced professional to prevent a repeat failure. When hiring a contractor, ask about their specific waterproofing method, request references from similar repair projects, and verify WCB Alberta coverage and general liability insurance. Get matched with a bathroom renovation contractor for a free estimate through Calgary Bath Remodeling and the Calgary Construction Network.

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Looking for experienced contractors? The Calgary Construction Network connects homeowners with qualified professionals:

• The Original Workshop
• Upper Cut Landscaping LTD
• Wise Abatement
• Mike’s Restoration Service
• Alpine Exteriors siding and roofing