How to Install an AKW Tuff Form on a Wooden Floor

Fitting an AKW Tuff Form on a wooden (timber) floor is one of its biggest strengths — the former is purpose-designed to drop into a timber joist floor at just 22mm deep, suiting a standard 18mm floorboard plus 4mm plywood overlay. This guide explains the process.

Important: this is a general overview. Always follow the official AKW installation instructions supplied with your former, comply with Building Regulations, and use a qualified installer for structural, plumbing and waterproofing work.

What you'll need

• AKW Tuff Form former and a compatible gravity or pumped waste
• Tanking (waterproofing) kit
• Timber for noggins/support, plus screws and adhesive
• Jigsaw, drill/driver, spirit level
• Your chosen floor finish — tiles or safety vinyl

Step 1: Plan around the joists

Lift the existing floorboards in the showering area and assess the joists. You'll need clearance below the floor for the waste and pipework. The original Tuff Form has a fixed waste position; if your joists fall awkwardly, the Tuff Form8 — with up to 15 waste positions — makes it far easier to avoid an obstructing joist. Plan the waste run with adequate fall to your soil stack.

Step 2: Create the support deck

The former must be fully supported across its whole underside — it should never bridge across open joists unsupported. Fit noggins between joists and lay a continuous deck (e.g. plywood) so the former sits on a solid, level base. The Tuff Form is designed to be recessed so its top finishes flush with the surrounding floor level once your finish is added.

Step 3: Cut the opening for the waste

Mark and cut the opening for the waste body so it drops below the deck. Dry-fit the former and waste together to confirm everything lines up and the former sits flush.

Step 4: Fit the waste and test

Connect the waste to the former and to the drainage run beneath the floor, following the waste manufacturer's instructions. Run a quick water test for leaks before fixing the former down — access is easy now and difficult later.

Step 5: Bond and fix the former

Bed the Tuff Form onto the deck using a suitable adhesive across the full underside so there are no voids. The ribbed underside grips the substrate and eliminates float or slippage during installation. If you need to trim the former to fit the opening, it can be cut to within 150mm of the waste without affecting strength or water integrity.

Step 6: Tank (waterproof) thoroughly

Apply your tanking kit over the former, across the surrounding floor and up the walls. On timber floors this is especially important because timber moves — pay close attention to the former-to-floor joint, the waste, and any board joints. Thorough waterproofing is the single most important step in a successful wet room.

Step 7: Lay your floor finish

Once cured, lay tiles or weld safety vinyl, trimming neatly to the waste grate and maintaining the fall so water drains freely.

Frequently asked questions

Can you fit a wet floor former on a wooden floor?

Yes — the AKW Tuff Form is designed for timber joist floors. At 22mm deep it suits an 18mm floorboard plus 4mm ply, and it's recessed so it finishes flush with the surrounding floor.

Does the former need full support underneath?

Yes. It must be fully supported across its entire underside on a continuous deck — it should not bridge open joists. Fit noggins and a plywood deck to create a solid, level base.

What if a joist is in the way of the waste?

Consider the Tuff Form8, which offers up to 15 waste positions in a rotatable grid, making it much easier to avoid an obstructing joist without cutting structural timber.

How do I stop the former moving?

Bond it across its full underside with a suitable adhesive; the ribbed base grips the deck and prevents float or slippage during installation.

Ready to start?

Browse the AKW Tuff Form range and choose your size and waste. See also our buying guide, our concrete floor guide, and whether you can install a wet room upstairs.