How do I convert a bathtub to a curbless shower in my Calgary home?

Converting a bathtub to a curbless (zero-threshold) shower is one of the more complex bathroom renovation projects, typically costing $5,000 to $12,000 in Calgary, and it requires professional installation due to the structural floor modifications involved. A curbless shower eliminates the raised threshold entirely, creating a seamless transition from the bathroom floor into the shower — ideal for accessibility, aging-in-place planning, and modern design aesthetics.

The biggest challenge with a curbless shower conversion is achieving proper drainage slope within the existing floor structure. A standard shower floor must slope at approximately 1/4 inch per foot toward the drain, but a curbless shower also requires the bathroom floor outside the shower to slope gently toward the shower area — or at least sit slightly higher — so water doesn't escape into the rest of the bathroom. In many Calgary homes, this means modifying the subfloor and potentially the floor joists to create a recessed shower pan area. In homes built on a concrete slab (common in bungalows and some older Calgary neighbourhoods), the concrete may need to be cut and a new drain line routed — a job that involves jackhammering and adds $1,500–$3,000 to the project. In homes with a wood-framed floor, the joists can sometimes be notched or the subfloor lowered to create the necessary slope, though this requires a building permit and structural assessment.

The waterproofing requirements for a curbless shower are even more demanding than a standard shower because there's no curb to act as a secondary water barrier. The entire shower floor and a portion of the surrounding bathroom floor must be waterproofed with a continuous membrane system. Schluter Kerdi with a bonded drain assembly is the preferred system for curbless showers in Calgary — the membrane bonds directly to the drain flange, creating a watertight connection with zero tolerance for error. A linear drain (channel drain) installed along one wall is the most popular choice for curbless showers because it requires slope in only one direction, simplifying the floor work. Linear drains run $300–$800 for quality units from manufacturers like Schluter, QuARTz by ACO, or Infinity Drain.

Permits and Code Requirements

A tub-to-curbless-shower conversion in Calgary requires a plumbing permit because you're relocating the drain (bathtub drains and shower drains are in different positions and may be different sizes). If floor joists are being modified, you'll also need a building permit. The City of Calgary Planning and Development department processes these permits, and a Safety Codes Officer will inspect the work at rough-in stage (before the floor is tiled) and at final completion. Permit costs run $75–$350 depending on scope. Do not skip permits — unpermitted structural and plumbing work must be disclosed at resale and can void your home insurance.

Calgary's chinook-driven temperature swings make material selection critical for curbless showers. The floor-to-shower transition has no curb to absorb movement, so flexible grout and premium silicone caulk rated for extreme temperature ranges are essential at all transition points. Calgary's hard water will deposit minerals on tile surfaces — large-format porcelain tile ($8–$18 per square foot for materials) with fewer grout lines is both a practical and aesthetic choice for curbless shower floors. Choose a tile with adequate slip resistance (a coefficient of friction of 0.42 or higher when wet) for safety.

This is emphatically not a DIY project. Curbless showers require expertise in structural assessment, plumbing relocation, precision waterproofing, and tile installation with exact drainage slope. A waterproofing failure in a curbless shower is especially damaging because water can flow freely out of the shower area and into the subfloor. Hire a bathroom renovation contractor experienced specifically with curbless shower installations, verify their WCB Alberta coverage, and ask to see completed curbless shower projects. Get matched with experienced Calgary bathroom renovation contractors for free through the Calgary Construction Network.

---

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

• Mike’s Restoration Service
• Radon Lab
• Calgary Custom Concepts
• Calgary Garage Builders Ltd
• Bracha Concrete & Coatings Inc.