Free Brass Samples: Floating Floor Thresholds, Gap Rules for Fitters

The right threshold for floating floors depends on the height relationship between the two surfaces, and it must always leave the expansion gap free beneath it. Use a T‑moulding where heights match, a reducer where they differ, and an end cap or custom scribed profile against a fixed upstand. Exterior doors add one extra job: weatherproofing the joint.

TL;DR:

Measure finished heights on both sides with underlay and flooring thickness before choosing a profile, because bare-subfloor measurements miss the underlay thickness.

A manufacturer specifies 3/8 inch for rooms up to 50 feet and 1/2 inch for larger areas, increasing clearance for long runs or heavy furniture.

Fasten the threshold to the substrate, never through floating boards, and leave the expansion gap empty after removing spacers to prevent movement restriction.

At exterior doors, carry the moisture barrier to the door line, seal only the exposed outside seam, and check full door swing before fixing the threshold.

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Which threshold profile suits which doorway?
How do you measure for a threshold and set the expansion gap?
What changes at an exterior door threshold?
How do you fit a threshold on a floating floor, step by step?
What should you check before choosing a profile?
Why is a solid brass door bar the premium choice?
An installer’s view: what actually goes wrong
Where can you get solid brass door bars and free samples?
FAQ
Sources

Which threshold profile suits which doorway?

Most doorways fall into one of four situations, and each has a profile built for it.

T‑moulding: bridges two floors at the same height, such as laminate in a hallway meeting laminate in a living room. It covers the gap and lets both floors move independently.
Reducer strip: ramps down from the floating floor to a lower surface like tile or vinyl. Use it wherever the two heights differ.
End cap or square nose: finishes the floor against a rigid barrier such as a patio door track, a fireplace hearth or a fixed upstand.
Baby threshold or custom scribed solution: suits non‑standard cases, such as a metal sill whose height does not match any stock strip. Flooring Clarity describes trimming one side of a profile so the other side still covers the floor edge.

A bar cannot rescue a poor subfloor. If the two surfaces sit at very different levels, fix the levels first and then choose the profile.

How do you measure for a threshold and set the expansion gap?

Measure the finished floor heights with the underlay in place, before the final boards go down. Measuring a bare subfloor gives you the wrong answer by exactly the thickness of the underlay.

Lay the underlay in the doorway and note its thickness.
Add the plank or tile thickness to get the finished height on each side.
Subtract one height from the other to find the difference, then pick the profile.
Mark the expansion gap, then confirm the moulding’s coverage is wider than the gap plus your cut edge.

Floating floors expand and contract, so the gap is not optional. One manufacturer guide specifies 3/8 inch for rooms up to 50 feet and 1/2 inch for larger areas, and says to increase the gap for very long runs or heavy furniture.

Industry code: the WPIF code of practice for floating floors advises movement gaps where panels abut rigid upstands. It also recommends treated timber battens beneath the floating layer at load points to prevent localised compression.

The fixing principle is simple: attach the moulding to the substrate, or use a clip or slot system that lets the floor slide. Never fix it through the floating boards.

What changes at an exterior door threshold?

Exterior doors add weather, movement and clearance to the same expansion-gap problem.

Choose the solution to suit the sill. A baby threshold or custom scribed profile works when no standard strip matches the sill height.
Extend the moisture barrier. Carry it up to the door line so water cannot track under the floor.
Seal the outside, not the gap. Use exterior-grade caulk on the exposed external joint, and keep it out of the expansion gap beneath the moulding, as Flooring Clarity advises.
Check door clearance. Swing the door fully before fixing anything. A practical guide to interior door fitting is useful for understanding clearances.
Think about access. Keep the rise gentle so wheelchairs, pushchairs and walkers can cross without catching.

Pro Tip: Dry-fit the door and the threshold together before any glue or caulk goes on. Moving a bar after sealing is far harder than adjusting it dry.

How do you fit a threshold on a floating floor, step by step?

Check the substrate is flat and clean, and confirm final heights with the underlay laid.
Fit spacers to hold the expansion gap, and cut the boards short of the threshold line.
Dry-fit the moulding over the gap to confirm coverage and level.
Mark the fixing points on the substrate, not on the floating boards.
Fix the moulding with screws into the substrate, or use a clip system or suitable adhesive.
Remove the spacers once the bar is secure, leaving the gap clear beneath it.
Seal only exposed external seams, and leave the gap itself empty.

The most common errors are skipping the gap entirely and fixing the bar through the floating boards, which locks the floor in place and causes lifting or cracking later.

What should you check before choosing a profile?

Run through this short checklist at your site survey:

The measured height difference between the two floors.
The traffic level, since a busy hallway needs a tougher bar.
Moisture exposure, such as a back door or bathroom.
Accessibility needs.
The finish match to your floor, skirting and door furniture.
The underlay thickness included in your measurements.

Then ask your supplier these questions:

How wide is the coverage, and does it span the gap?
What fixings come with it?
Can the profile be trimmed or scribed on site?
Is it suitable for exterior or damp conditions?

Why is a solid brass door bar the premium choice?

Wooden, plastic and rubber trims are examples of cheaper trims that may not last as well in a busy doorway: they can split, bend, dent or wear through. Our door bars are solid brass, so they hold their shape under daily footfall.

Durability: solid brass resists bending, splitting and denting, unlike cheaper trims.
Finish: we hand finish every bar in a choice of luxury powder-coated finishes, so you can match your door furniture.
Free samples: order a sample to check colour and fit against your floor before you buy.
Installation: check the coverage dimensions, and confirm the profile can be trimmed or scribed if the doorway needs it.

Pro Tip: Hold the sample against the floor in the doorway itself, in daylight and under artificial light, since finishes can read differently in each.

An installer’s view: what actually goes wrong

On site, the same few mistakes appear again and again: no expansion gap, a threshold screwed through the floating boards, and a profile that does not quite cover the gap. The fix is just as consistent. Measure twice, preserve the movement, fix to the substrate, and seal only the exposed seams.

— Matt

Where can you get solid brass door bars and free samples?

We supply UK-made, solid brass door bars in hand-finished colours, with free samples so you can check the match first.

Order a free sample, then pick the profile that covers your gap.

FAQ

What can I use instead of a threshold?

You can use an end cap or edge trim where the floor meets a fixed barrier, or a scribed profile for awkward gaps. Whatever you choose, it must still cover the expansion gap without restricting the floor’s movement.

Is 7mm laminate flooring too thin?

Not necessarily, but thinner laminate needs a flatter subfloor and a careful choice of reducer so the step is smooth. Always measure the finished height with underlay before choosing your profile.

Do floating floors settle?

Floating floors move with temperature and humidity rather than settling. That is why a clear expansion gap beneath the threshold matters, as set out in the WPIF code of practice.

Do I need a transition strip between wood and tile?

Yes, a reducer or similar profile is usually needed to cover the gap and smooth any height difference. Our tile to tile threshold and transition ranges cover these joins.

Sources

The movement-gap and fitting advice here draws on the sources linked in the body. Check exact coverage dimensions on each product page before you buy.

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