Can You Install a Wet Room on an Upper Floor? (Ground, First or Second Floor)

One of the most common questions we're asked is: “Can I install a wet room on an upper floor — a first or second floor — or only on the ground floor?” The short answer is yes, you can — wet rooms are routinely installed upstairs — but there are a few important considerations, and the AKW Tuff Form is particularly well suited to upper-floor installs. Here's what you need to know.

Important: this is general guidance. Upper-floor wet rooms involve structural, drainage and waterproofing decisions that should be confirmed by a qualified installer and comply with Building Regulations.

Yes — you can install a wet room upstairs

Ground floor, first floor or second floor, a level-access wet room is achievable on a timber upper floor. The two things that change as you go up are drainage and waterproofing — get those right and an upstairs wet room performs just as well as a ground-floor one.

Consideration 1: drainage and fall

On a ground floor you can often run a gravity waste into the slab or below the joists. Upstairs, the depth available between the joists is limited, which can make achieving the required fall for a gravity waste trickier.

This is where the Tuff Form's options help:

• Its slim 22mm depth sits neatly within a timber floor build-up.
• Low-depth gravity wastes are available where joist depth is tight.
• Where gravity simply isn't possible, a pumped waste (PGTF) pumps waste water away — making an upper-floor wet room viable even with limited fall.

Consideration 2: the floor structure

The former must be fully supported across its underside on a solid, level deck — it should never bridge open joists. On an upper floor you'll typically fit noggins between the joists and lay a continuous plywood deck. If a joist obstructs your ideal waste position, the Tuff Form8 — with up to 15 waste positions — lets you reposition the waste rather than cutting structural timber. If in any doubt about loadings or notching joists, consult a structural engineer.

Consideration 3: waterproofing is non-negotiable

Waterproofing matters everywhere, but upstairs the stakes are higher — a leak doesn't just damage the floor, it can come through the ceiling below. A full tanking (waterproofing) kit must be applied over the former, across the floor and up the walls, with particular care around the waste and the former-to-floor joint. Don't cut corners here.

Why the Tuff Form suits upstairs installs

• Slim 22mm profile — fits standard timber floor build-ups
• Strong GRP construction — supports up to ~60 stone (≈381kg)
• Flexible waste options — gravity, low-depth, or pumped for tricky fall
• Trimmable to fit awkward upstairs room layouts

Frequently asked questions

Can you put a wet room on the first or second floor?

Yes. Wet rooms are commonly installed on upper timber floors. The main differences from a ground-floor install are achieving drainage fall and ensuring thorough waterproofing.

How do you drain an upstairs wet room if there's no fall?

Where a gravity waste can't achieve enough fall within the floor depth, a pumped waste such as the AKW PGTF can be used to pump waste water away, making an upper-floor wet room possible.

Is a timber upstairs floor strong enough for a wet room?

Generally yes, provided the former is fully supported on a continuous deck and the floor structure is sound. For any concerns about loadings or notching joists, consult a structural engineer.

Is waterproofing more important upstairs?

The principles are the same, but the consequences of a leak are greater because water can reach the ceiling below. A full tanking kit, carefully applied around the waste and joints, is essential.

Planning an upstairs wet room?

The AKW Tuff Form range has the sizes and waste options to make it work. Read our buying guide and our step-by-step guide to installing on a wooden floor. Need advice? Our team is happy to help.