Fit Loose Matwell Frames First Time: 17–23mm Depth for UK Contractors

A loose matwell frame is a self-contained border that sits on top of an existing floor to hold an entrance mat flush with its edges, with no cutting into the subfloor. Specify it for retrofit jobs, leased units or any site where building a recessed well isn’t practical, choose 17mm or 21-23mm depth based on mat thickness, and check matwell frame sizes before ordering from a suitable supplier.

TL;DR:

Choose 17 mm for thinner mats or 21 to 23 mm for heavier commercial mats, adding underlay thickness and checking clearance against the door’s swing.

Measure the opening at both ends and the middle, then order by its narrowest inside width and length to prevent gaps or rocking.

Expect £30 to £80 per metre, with bespoke shapes and premium finishes near the upper end; approve the technical drawing before manufacture.

For routes used by wheelchairs or trolleys, specify a bevelled edge; PVC suits lighter traffic, while metal withstands repeated impacts on busy commercial entrances.

Clean mats weekly in busy commercial entrances and monthly in quieter homes or offices, then wipe grit from the frame to protect its finish.

Qualitycarpettrims

Finish Flooring Transitions with Confidence

Explore solid metal door bars and flooring trims, hand finished in 10 finishes for practical, polished transitions between floor types.

Explore flooring trims

When to choose a loose matwell frame over a recessed well
Why solid brass and powder-coated finishes outlast cheaper trims
How to measure a matwell for a loose-laid frame
Fitting a loose matwell frame on site
Edge profiles, ramping and trip-safety
Cleaning, maintenance and replacing a loose-laid mat
Specification and ordering checklist
Why contractors specify our matwell frames
A fitter’s note: three rules worth following
Ordering, samples and technical support for solid brass, hand-finished matwell frames in a range of finishes, cut to size with pre-drilled corners available where mechanical fixing is specified, may be offered by specialist suppliers. Frames are often made in the UK with fast delivery once dimensions and finish are confirmed.
FAQ
Sources

When to choose a loose matwell frame over a recessed well

The decision usually comes down to how much disruption a site can tolerate. A loose-laid frame needs no structural work and can be fitted in under an hour, which makes it the practical choice whenever the floor underneath can’t or shouldn’t be touched. A recessed matwell, by contrast, delivers a flush finish but usually requires a built-in well formed during construction or a major refurbishment.

Loose-laid frames tend to suit:

Retrofit projects where the subfloor is finished and reopening it isn’t an option.
Leased commercial units, where landlord consent for structural alterations is hard to secure.
Historic or listed buildings, where cutting into original flooring isn’t permitted.

Recessed matwells suit new-build projects specified at the design stage, and accessibility-critical entrances where a completely flush threshold matters more than ease of replacement. On high-traffic sites, weigh up how often the mat will need lifting for cleaning or replacement. A loose frame makes that routine, a recessed well makes it a bigger job. Refurbishment timing matters too: if the floor covering either side of the entrance is due for replacement soon, fitting a loose frame now and revisiting the layout later avoids wasted work.

Why solid brass and powder-coated finishes outlast cheaper trims

Matwell frames take constant foot traffic, trolley wheels and the occasional door slam, so the material choice decides how long the frame actually lasts. Trims made from wood, plastic, rubber or aluminium are common on the market, but they split, bend or dent under sustained use, and once the edge deforms the mat starts to rock or lift at the corners. Our frames are made from solid brass and powder-coated in 10 luxury finishes, which resist the bending, splitting and corrosion that shorten the life of lighter alternatives.

Specifying the right finish matters as much as the material. Match the frame finish to adjacent door bars or threshold strips so the entrance reads as one considered scheme rather than a mismatched patch. On cost, a brass frame sits at the upper end of the price band, but a frame that needs replacing every couple of years because it’s cracked or corroded ends up costing more across the life of the building.

Pro Tip: Order a sample in your chosen finish before committing to a full run, colour and texture can read differently under site lighting than on a screen.

How to measure a matwell for a loose-laid frame

Getting the dimensions wrong is the single most common reason a loose matwell frame arrives and doesn’t fit. Specification notes for recessed matwells stress that frames are defined by width, length and depth, and these three measurements have to match the mat exactly or you end up with rocking or gaps at the edges. The same discipline applies to a loose-laid frame sitting on top of the floor.

Measure width and length to the inside edge of where the frame will sit, not the outside, since the mat fits inside that boundary.
Take each measurement at both ends and the middle, entrances are rarely perfectly square, and the narrowest point sets your order size.
Measure depth by adding the mat thickness to any underlay or backing, then check against standard depth options of 17mm for thinner matting and 21 to 23mm for heavier commercial mats.
Check the door swept arc against your chosen depth, a frame that’s too deep will catch the door or stop it closing fully.
Note any slope towards the exterior for drainage, and record whether the opening is square or slightly out of true.
Write every measurement, the finish code and the depth onto your order form before contacting a supplier, so nothing gets guessed on the phone.

A retrofit matwell frame is designed around exactly this kind of on-site measuring, which is why it avoids the door-binding problems that come from ordering on assumption rather than a tape measure.

Fitting a loose matwell frame on site

Installation is straightforward once the substrate is right, but skipping preparation is where most callbacks start. A product installation guide for entrance matting warns that loose-laid products have no clips or joining pieces holding them together, and that an uneven base will damage the mat over time, so flatness matters more than it might seem.

Clear debris and check the substrate is flat, any high spots or old adhesive residue will show through as a rock under the finished frame.
Remove any existing frame or threshold strip completely, including old fixing screws or adhesive pads, rather than fitting over them.
Choose your fixing method: adhesive suits a clean, dry substrate, while mechanical fixing into screed or a timber subfloor gives a more permanent hold on high-traffic routes.
Where the frame is pre-drilled for mechanical fixing, mark and drill the substrate to match before offering the frame up, rather than drilling through the frame itself.
Fit ramped edging where the entrance carries trolleys, pushchairs or wheeled luggage, PVC ramps suit lighter domestic use and metal ramped profiles cope better with sustained commercial traffic.
Bed the frame down, check it sits flush at every edge, and test by walking across it before fitting the mat.
Fit the mat into the frame, check it sits flat with no rocking corners, and seal any exposed edge where water could track underneath.

Pro Tip: Walk the finished installation in both directions, including with a loaded trolley if the site uses one, before calling the job complete.

Edge profiles, ramping and trip-safety

The edge detail is often the difference between a frame that looks tidy and one that becomes a trip hazard. Ramped PVC edging works well for domestic or light commercial entrances where the height difference is small, while a ramped metal profile holds up better where trolleys, wheelchairs or heavy footfall cross the threshold several hundred times a day.

Specify a bevelled or chamfered edge on any route used by wheeled trolleys or wheelchairs, a square edge will catch wheels and create a jolt.
Use PVC ramped edging for lighter domestic entrances where appearance matters as much as durability.
Use a metal ramped profile on commercial or high-traffic routes where the edge needs to survive repeated impact.
Note the edge detail explicitly on drawings or order forms, since “ramped” alone doesn’t specify material or angle.

Cleaning, maintenance and replacing a loose-laid mat

One advantage of a loose-laid system is that the mat lifts straight out of the frame for cleaning, with no fixings to undo first.

Lift the mat for cleaning on a schedule set by footfall: busy commercial entrances need this weekly, quieter domestic or office settings can usually manage monthly.
Vacuum or hose down the mat away from the frame, and wipe the inside of the frame itself to clear grit that would otherwise scratch the finish.
When replacing a worn mat, check its dimensions against your original measurements before ordering, a mat even a few millimetres undersized will rock in the frame.
Inspect the frame edges periodically, our solid brass and powder-coated finishes resist the denting and corrosion that cause gaps to open up over time.

Specification and ordering checklist

Before placing an order, gather every field a manufacturer needs to cut the frame correctly:

Internal width x length x depth, measured to the inside edge as set out above.
Mat thickness and any underlay, so depth allowance is accurate.
Finish code, matched to adjacent door bars or trims where relevant.
Ramped edge requirement, specifying PVC or metal.
Whether pre-drilled corners are needed for mechanical fixing.
Fixing method: adhesive or mechanical.
Required delivery lead time.

Expect to pay in the region of £30 to £80 per metre, with bespoke shapes and premium finishes pushing costs towards the upper end. Request a sample in your chosen finish and confirm a technical drawing before manufacture starts, it’s far cheaper to correct a drawing than a finished frame.

Why contractors specify our matwell frames

Matwell frames are often made from solid brass and may come in a range of finishes, contrasting with cheaper alternatives made from other materials that can split, bend or dent under regular traffic. Our depth guidance and sizing pages set out exact dimensions so fitters can order against real tolerances instead of guesswork, and free samples let you check a finish on site before committing to a full order. Technical advice is available for anyone measuring an irregular or non-standard opening.

A fitter’s note: three rules worth following

Most matwell problems trace back to one of three shortcuts. Measure at several points along each side and record the inside-edge dimension, not the outside. Check door clearance against your chosen depth before you order, not after. Specify a ramped edge wherever trolleys cross or the premises is leased, it avoids the callback that follows a sharp lip or a landlord dispute.

— Matt

Ordering, samples and technical support for solid brass, hand-finished matwell frames in a range of finishes, cut to size with pre-drilled corners available where mechanical fixing is specified, may be offered by specialist suppliers. Frames are often made in the UK with fast delivery once dimensions and finish are confirmed.

To get a frame right first time:

Send us your width, length and depth measurements along with mat thickness and underlay allowance.
Request a free sample in your chosen finish before placing a full order.
Ask for a technical check on irregular or non-standard openings before we cut.

Browse our matwell frame range to see finish options and sizing, or get in touch with your measurements for a fast, accurate quote.

FAQ

What’s the difference between a loose matwell frame and a recessed matwell?

A loose matwell frame sits on top of the existing floor with no structural work, while a recessed matwell is built into the subfloor for a flush finish. Loose frames suit retrofit and leased sites, recessed wells suit new-build or accessibility-critical entrances.

What depth should I choose for a matwell frame?

Depth should match mat thickness plus any underlay, with 17mm suiting thinner domestic matting and 21-23mm suiting heavier commercial mats. Always check the chosen depth against the door’s swept arc before ordering.

How much does a matwell frame cost?

Loose matwell frames typically cost between £30 and £80 per metre, with bespoke shapes and premium finishes at the upper end. Our frames are solid brass, hand-finished in 10 luxury finishes, which sits within that range depending on size and finish.

Why do some matwell frames split, bend or dent?

Frames made from wood, plastic, rubber or aluminium are common but tend to split, bend or dent under sustained foot traffic and wheeled loads. Solid brass and powder-coated finishes resist that damage far better, which is why we don’t offer those lighter materials.

Can a loose matwell frame be used with underfloor heating?

Depth allowances need checking carefully where a heated foil mat sits under the floor covering, since the extra build-up changes the available depth for the frame and mat. Always measure the finished floor height on site rather than assuming standard depths will clear it.

Blog