Shower Rooms vs Wet Rooms

The choice between a shower room and a wet room comes down to budget, floor construction, intended users, and the look you want. Both deliver a shower; what differs is how water is contained, how the floor drains, and what happens to the surrounding structure over time. Getting the waterproofing right is the defining factor in both cases.

A shower room uses an enclosed shower tray, acrylic, stone resin, or tile-over, paired with glass screens or a full enclosure. A wet room has no tray; the entire floor is waterproofed, graded to a drain, and tiled flush, so water disperses across the floor surface before draining away. Each has a distinct cost profile, maintenance pattern, and suitability for different households.

Definitions and How They Work

Shower room, a bathroom containing a shower as its primary or only wash facility, typically with an enclosed shower tray and screen. The tray contains and directs water to a single drain point. Waterproofing is limited to the shower area itself (the tray and the tiled splash zone behind it).

Wet room, a room where the entire floor (and often all four walls to full height) is waterproofed using a tanking membrane system before tiling. There is no shower tray; the tanked floor is laid to fall so water flows to a linear or point drain.¹ A partial wet room uses a screen or frameless glass panel to contain the primary spray zone while still leaving the floor level and open.

Waterproofing Systems

This is where most wet room failures originate. The waterproofing must be applied before tiling and must form a continuous, bonded layer across every surface water can reach.

Tanking membrane, a liquid-applied or sheet waterproofing layer applied to the substrate (screed, concrete, or timber floor). Liquid tanking (typically two coats of a flexible compound) is the most common approach; sheet membranes (polyethylene-backed systems fixed with bonding mortar) are used in high-specification installations. Joints, corners, and pipe penetrations must be reinforced with fabric tape before the membrane goes on.

Bonded membrane systems, such as Schluter’s DITRA or an equivalent, use a membrane bonded under the tiles that both waterproofs and uncouples the tiling from the substrate, reducing the risk of cracking caused by substrate movement.² These are particularly suited to timber subfloors in UK houses (which flex more than concrete).

For a shower room, tanking is typically applied only within the enclosure footprint and to the walls immediately behind the tray. For a wet room, all four walls (to at least 1,800mm height, or full height in compact rooms) and the entire floor must be tanked.

Floor Gradients and Drain Position

Building Regulations guidance gives no minimum fall for a wet room floor: Approved Document M asks only for a floor laid to shallow falls.¹ The minimum usually quoted by tanking and former manufacturers is 1:80 to the drain, that is, 12.5mm of fall per metre of floor; always follow the figure for the system you are using. Many installers prefer 1:60 (about 17mm per metre) for more reliable drainage.

On a concrete ground floor, the gradient is typically formed in the screed layer before tanking. On a timber upper floor, the options are:

• Recessing the joists and forming the gradient in a new screed pour (structural work, adds cost)
• Using a proprietary wet room former (a pre-formed sloped tray that sits on the existing subfloor and raises the finished floor level by 30–75mm at the edges)
• Installing a linear drain at the wall edge, requiring a single gradient across the whole floor (simpler than a central point drain)

A point drain at the centre of the room requires a four-way gradient (the floor slopes in from all sides). A linear drain at one wall requires only a one-way slope, easier to form and tile.

Costs Compared (UK, 2026)

Costs rise with room size, tile specification, and bespoke glass. A high-end wet room with large-format stone tiles, frameless glass, and a concealed linear drain can exceed £10,000.

Space Requirements

A shower room tray can be as small as 700×700mm (a corner tray), though 800×800mm is the practical minimum for most adults. A standard 1,200×800mm rectangular tray is comfortable and fits most bathroom layouts.

A wet room can theoretically be any size, but compact wet rooms (under 1,500mm in any dimension) make achieving adequate gradient harder and feel cramped in use. A minimum of 900×900mm of clear shower space (within the wetted area) is recommended; 1,200×800mm or larger is preferable.

Suitability by Use Case

Building Regulations: Part M (Accessible Design)

Part M of the Building Regulations covers access to and use of buildings. Every new dwelling must meet Category 1 (visitable); the higher Category 2 (accessible and adaptable) and Category 3 (wheelchair user) standards apply only where the planning permission imposes them as a condition.¹ Where Category 2 applies, the guidance asks for:

• Provision for a potential level access shower in the bathroom, if one is not provided elsewhere in the home¹
• In a two or three storey home with three or more bedrooms, an installed or potential level access shower in the entrance-storey WC room¹
• Walls, ducts and boxings in the bathroom and shower room strong enough to take grab rails and seats, at a load of up to 1.5 kN/m²¹

A wet room naturally satisfies the level-access requirement. Approved Document M defines a level access shower as a step-free area with no lips or upstands, laid to shallow falls, so a raised shower tray does not meet it; a tile-in tray or former set flush with the floor can.¹

In Category 3 (wheelchair user) dwellings the entrance storey needs a room with a WC, basin and installed level access shower, and every room with an installed level access shower must be built as a wet room.¹

Part M’s dwelling requirements are written for new homes: requirement M4(1) does not apply to an extension to a dwelling, and refitting a shower room in an existing house does not bring in the Category 2 or 3 standards.¹ Designing for accessibility from the outset is still good practice.

Pros and Cons Summary

For most UK households fitting a new shower in a standard bathroom, a quality shower tray with a low-profile upstand and frameless screen offers the best balance of cost, reliability, and appearance. A wet room becomes the clear winner for step-free access requirements, large or open-plan bathroom layouts, and high-specification renovations where the additional cost is justified.