Bath to Walk-In Shower Conversion in Portugal: Complete Guide

In Portugal, the majority of older apartments were built with a bathtub as standard. In practice, for many households — especially adults living alone or couples without young children — the bath is rarely used. A walk-in shower is faster, uses less water, and transforms how a bathroom feels. The conversion is one of the best-value renovations you can make.

Why Convert? The Practical Case

Beyond personal preference, there are several solid reasons to convert a bath to a walk-in shower in Portugal:

• Space recovery: a standard bath occupies 1.5–1.7 m² of floor space. A walk-in shower at 90×90 cm uses about 0.81 m². That freed space can transform a cramped bathroom.
• Accessibility: stepping over a bath rim becomes increasingly difficult with age or mobility issues. A flush-floor shower with no threshold is much safer and more comfortable.
• Water use: a 5-minute shower uses approximately 40–60 litres. A bath uses 150–200 litres. Over a year, that's a significant water saving.
• Resale appeal: in the current Portuguese property market, a modern walk-in shower is often preferred by buyers and renters over an old bathtub.
• Modern aesthetic: a frameless walk-in shower with quality finishes simply looks better in a renovated bathroom than an old bath surround.

The Conversion Process: Step by Step

1. Assessment and planning: a qualified contractor surveys the existing bathroom — locating the waste pipe, checking floor structure, measuring the space, and advising on the best shower position and drainage option.
2. Demolition: the bath is removed. Surrounding tiles are taken off. The floor is opened to access the waste pipe and sub-floor structure.
3. Drainage installation: the existing bath waste (typically 40 mm diameter) may need upgrading for a shower waste (40–50 mm). The drain position is set — centre, corner, or linear channel along one wall.
4. Floor preparation: the sub-floor is levelled and sloped toward the drain (typically 1–1.5% fall). In apartments, this often involves a screed layer or specialist shower tray former.
5. Waterproofing: tanking membrane is applied across the entire shower zone — floor and walls to at least 1.8 m height. This is the most critical step. Poor waterproofing causes leaks into the apartment below.
6. Finish application: tiles, microcement, or stone are applied to the waterproofed surfaces. Floor finish must have adequate anti-slip rating (R10 or R11 for wet areas).
7. Glass panel or enclosure: frameless glass panel or full enclosure is installed. Frameless options (10 mm toughened glass) are the most popular for a contemporary look.
8. Fixtures: shower head, mixer tap or thermostatic valve, and any extras (hand shower, rainfall head, niche) are fitted and tested.
9. Final touches: grouting, silicone sealing, and final clean.

Cost of Bath to Walk-In Shower Conversion in Portugal

These prices include labour, waterproofing, tiling or microcement, drainage work, and a standard glass panel. They exclude sanitaryware and fixtures supplied separately, and any structural surprises uncovered during demolition.

Drainage Options: Which Is Right for You?

The drainage solution has a significant impact on both aesthetics and cost:

Linear channel drains are the most popular upgrade — they make the shower look larger, are easy to clean, and allow full floor tiles without awkward cuts around a centre drain.

Glass Options for the Shower Enclosure

The glass is often an afterthought but makes a significant visual and practical difference:

• Frameless panel (fixed glass): a single fixed glass panel, typically 90–120 cm wide. Simple, clean, budget-friendly. No opening — you enter from the open side. Best for walk-in showers with enough space to step in without splashing.
• Frameless pivot door: fixed panel plus a hinged door. More enclosed, works in smaller shower zones. Most popular choice in Portugal.
• Frameless sliding door: ideal when space in front of the shower is limited — door slides rather than opens outward. Slightly more complex mechanism.
• Wet-room (no glass): the shower zone is defined by the drain and floor slope only. Maximum openness. Requires excellent waterproofing across a larger area. Works best with microcement throughout.

Glass thickness: 8 mm is minimum, 10 mm is standard for quality installations. Avoid 6 mm glass — it flexes and feels flimsy.

Key Things That Can Go Wrong (and How to Avoid Them)

Bath-to-shower conversions are straightforward in experienced hands, but there are several common failure points:

• Inadequate waterproofing: the most common cause of post-renovation problems. Always ask your contractor what waterproofing system they use and whether it covers the full shower zone. A reputable contractor will waterproof 200 mm beyond the shower zone on floors, and full-height on walls.
• Insufficient floor fall: if the floor doesn't slope adequately toward the drain, water pools. This is a workmanship issue. Ask to inspect the slope before tiling.
• Undersized waste pipe: a bath waste is often 40 mm; a shower in active use needs at least 40 mm, ideally 50 mm. If yours is currently 40 mm and the connection run is long, discuss upgrade options with your plumber.
• Condensation and ventilation: showers produce significant steam. If the bathroom doesn't have adequate ventilation, mould will form. Ensure an extractor fan with adequate flow rate (minimum 15 l/s for a shower room) is installed or upgraded as part of the conversion.
• Anti-slip flooring: any tile in the shower zone must have an anti-slip rating of R10 or higher. Smooth or polished tiles are dangerous when wet. Your contractor should confirm the slip rating of any tile specified.

Do You Need a Permit to Convert a Bath to a Shower in Portugal?

No permit is required for internal bathroom works in Portugal, including bath-to-shower conversions. This falls under obras de conservação (maintenance works) — no municipal licence needed, no notification required. The only exception would be if the work involved structural changes to load-bearing walls or was in a listed building.

See our full guide on renovation permits in Portugal for more detail on what does and doesn't require a permit.

Timeline: How Long Does It Take?

A bath-to-shower conversion, done as a standalone project:

• Simple conversion (keeping existing tiles on walls, new shower zone only): 3–5 working days
• Full bathroom renovation including the conversion: 10–20 working days depending on size and finish

The main variable is the curing time for waterproofing and screeds — these must fully cure before tiling, and cannot be rushed without risking failure.

For a broader look at bathroom renovation options, see our bathroom renovation service or read our guide on small bathroom renovation ideas.