How do I deal with a step or a level change between two floors?
The four profiles that resolve a height difference at a doorway, how to choose between them, and when the answer is to build the low side up instead.
- Difficulty
- intermediate
- Time
- 1 hr
- Read
- 3 min
- Safety
- warning
Short answer
Same height: a T-bar covers the gap on both sides. A few millimetres: a ramp or reducer profile, flush on the low side, rising to the high one. A protected edge: a lipped L-shaped trim. Anything larger: build the low floor up, or form a proper visible step. Never fix a trim through a floating floor.
New flooring almost always changes the floor height, and doorways are where the change becomes visible and where it matters. Getting this detail right is the difference between a job that looks finished and one that has an obvious step, a bar that keeps coming loose, or a trip point in every doorway.
Safety
What you'll need
- a straight edge and a small level
- the correct threshold profile
- a fine-tooth saw or a hacksaw for metal profiles
- fixings suited to the subfloor
- adhesive designed for threshold bars (optional)
Step by step
- Measure the actual difference at the doorway.Lay a straight edge across the opening from one finished floor to the other and measure the gap. Do it at both ends of the opening — doorways are frequently not level across their width.
- Decide whether the difference should be removed instead of covered.Building the low side up with a levelling compound, a plywood packer or a thicker underlay is often better than fitting a ramp, particularly in a main circulation route or where a wheelchair or a walking frame has to cross.
- Choose the profile for the difference you have.Equal or near-equal heights: a T-bar. Small difference: a ramp or reducer. An exposed cut edge on the higher floor: a lipped or L-shaped trim. A large difference: a formed step, made visible.
- Check that both expansion gaps still work.On a floating floor, the profile must cover the expansion gap on each side without touching or pinning either floor. This is why a T-bar has a stem that sits in the gap rather than a base that clamps the floor.
- Fix to the subfloor, never through a floating floor.Most profiles have a base track screwed to the subfloor with the visible bar clipping into it, or are bonded to the subfloor. A screw driven through a floating floor stops the raft moving and causes peaking somewhere in the room.
- Set the bar in the right place.Under the closed door, centred on the door line, so it is not visible from either room when the door is shut. This is the standard and it looks wrong when it is not followed.
- Cut it accurately and finish the ends.Cut metal profiles with a hacksaw and file the ends. A trim that is a couple of millimetres short leaves a gap at the architrave that collects dirt and looks like an afterthought.
- Check the door still clears.Adding a threshold bar can reduce the clearance under a door that was previously fine. Check the door swings freely over the finished bar before you fix it permanently.
- Make an unavoidable step obvious.A different material, a contrasting nosing, or a light. A step that is hidden by a continuous carpet or a matching floor either side is the arrangement that causes falls.
If it doesn't work
The threshold bar keeps coming loose
Cause: Fixed into a floating floor which is moving, or into a subfloor that is not sound at that point — Fix: Refix to the subfloor with a proper track and fixings suited to the material. On concrete, use plugs or a bonded track rather than the supplied pins.
Carpet has pulled away from the bar
Cause: The carpet was hooked onto the bar's teeth without being stretched, or the wrong bar was used — Fix: Use a bar with a carpet gripper edge, and stretch the carpet into it. A plain flat bar does not hold carpet.
The bar is a trip point in its own right
Cause: Too tall a profile for a small difference, or a bar sitting proud of both floors — Fix: Change to a lower-profile trim or, better, level the low side up and use a flat T-bar.
A new floor has created a step at every doorway
Cause: The new floor is thicker than the old one throughout — Fix: Consider building up the adjoining rooms, or accept ramps and make them consistent. Consistency is what makes a house safe to walk around in the dark.