Yes, but a timber subfloor needs three things a concrete floor does not: a rigid support for the drain independent of the floorboards, a sealing flange for continuous waterproofing, and a confirmed outlet route between the joists.
1. Rigid support is mandatory
Timber deflects. A drain fixed directly to floorboards will move as the floor moves, cracking tile or breaking the waterproofing seal. The drain must sit on a solid base — typically a plywood packer or a timber/steel noggin frame fixed between joists.
2. Waterproofing must be continuous
Timber tolerates water ingress far less than concrete, and the damage is often hidden until it is extensive. Specify a drain with an integrated sealing flange so the liquid membrane bonds directly to the drain body. Apply the membrane continuously from the wall, over the flange and around the body.
3. Check the joist route before ordering
| Check | Why |
|---|---|
| Joist direction | Determines whether a horizontal outlet can run parallel between joists |
| Joist depth and spacing | Determines whether the outlet and its fall fit |
| Existing services | Pipework and cabling may block the route |
| Floor build-up | Timber builds up differently from concrete |
A drain that fits the floor may not fit the structure underneath. Confirm the route before the drain is ordered.
Additional points for timber
- Movement joint — where the span is large, allow a movement joint between the tile field and the drain frame.
- Moisture content — confirm the subfloor is dry and within tolerance before tiling; timber moves as it dries.
- Acoustic separation — in apartments, a decoupling layer under the drain reduces impact noise transmission.
- Access — leave the hair trap accessible from above; do not create a situation requiring the ceiling below to be opened.
See our full wooden subfloor solutions page.