Walk-On Glass Floor Buying Guide

Everything you need to decide what to order when you are buying walk-on floor glass: how thickness relates to span, how the glass has to be supported, what non-slip treatment actually does, what the border and coating options are for, and how sizes and delivery work. If you want the regulatory side instead, loadings, balustrade requirements and what building control will look for, that is covered in our glass floor building regulations guide.

The short version

  • Floor glass is always toughened and laminated, two or three plies bonded together. Each ply is a structural layer in its own right, so the panel still carries the floor if one of them is broken.
  • It must be supported continuously on all four sides, with around 50mm of level bearing all round. Never in the middle, never on two sides only.
  • Thickness follows span and use: 25.5mm to about 1000mm, 31.5mm or 33mm beyond that, 39mm for commercial floors. Every span figure on this page assumes domestic loading unless it says otherwise.
  • Our invisible non-slip treatment reaches PTV 68 to 71 dry but only 19 to 23 wet. Anywhere genuinely wet or in public use wants a physical texture rather than a chemical treatment.
  • Shapes other than rectangles are routine, worked from a template or a drawing and quoted rather than ordered off the size bands.

On this page

What a glass floor is for

Nearly always, light. A glass floor brings daylight down into the room, cellar, hallway or basement underneath instead of shadowing it, and that is the reason most of these panels get specified. It is also why a glass floor earns its money in the places a window cannot reach.

It is worth being clear about the trade-off. Glass is not the ideal surface for a floor people live on: it is not what you want to be dragging chairs and tables across, standing a barbecue on, or setting furniture down on, and it shows every mark and footprint. Where the floor is in daily use, a glass panel set into a solid floor is usually a better answer than glazing the whole thing. You get the light where you need it and a normal floor everywhere else.

What walk-on floor glass is

Floor glass is always toughened and laminated. Each pane is heat treated so it is several times stronger than ordinary annealed glass, and two or three of those panes are bonded together with a structural interlayer.

The lamination is the safety part, and it does considerably more than hold the pieces together. Each pane is a structural ply in its own right, so if one is ever broken the remaining panes carry the load on their own and the panel still works as a floor. That is designed redundancy rather than a lucky outcome, and it is why a single sheet of toughened glass, however thick, is not a floor.

All our floor glass has polished edges as standard, with a 5mm radius to each corner. Our toughened and laminated glass guide explains what each process does and why floor glass needs both.

That redundancy is also the answer to spontaneous breakage, the rare case where a toughened pane fails on its own because of a microscopic nickel sulphide inclusion formed in the original float glass. It is a known property of toughened glass rather than a fault, and it is why glass is excluded from our 10 year warranty. Lamination does not make it any less likely, because every ply is toughened glass. What it does is make the consequence survivable: the interlayer holds the fragments and the remaining plies keep carrying the floor. The mechanism, the industry position and what heat soak testing to BS EN 14179-1 does and does not achieve are set out in the spontaneous breakage section of our glass guide.

How floor glass must be supported

Glass must be supported on all four sides. Never support a floor panel in the middle, and never on two sides only. Floor glass is sized to span between continuous edge supports, and a central or partial support loads the panel in a way it was not designed for.

Edge bearing is typically taken as around 1.5 times the glass thickness, so roughly 40mm on a 25.5mm panel. In practice we suggest 50mm of bearing all round as a belt and braces figure for most applications.

Allow for the bearing when you set out. The glass has to be larger than the clear opening by the bearing on each side, so a 1000 x 1000mm clear opening with 50mm bearing all round needs a 1100 x 1100mm panel.

The bearing also needs to be continuous and level. Point loads on the underside of a panel, high spots in a frame, or glass sitting directly on bare steel are all ways to break glass that was otherwise correctly specified. Neoprene support strips take up small tolerances and keep glass off steel.

Choosing a thickness

Floor glass is sized on the panel, not on a rule of thumb. Span, support conditions and what will be walking on it all matter, and we would rather size it with you than have you guess. As a broad steer:

  • 25.5mm, two 12mm panes. Domestic use and smaller spans. Suits panels up to around 1000mm in one direction, so a long narrow panel such as 2000 x 1000mm is fine, whereas 1000 x 1010mm is not. In most cases we advise 25.5mm up to about 1000 x 1000mm, and above that considering a thicker panel even where 25.5mm technically works.
  • 31.5mm, two 15mm panes. The usual choice for domestic floors, landings and walkways once you are past the 25.5mm range.
  • 33mm, three layers rather than two. Performance against 31.5mm is close to identical, so the reason people choose it is the third ply: it leaves more in reserve if one pane is ever damaged.
  • 39mm, our heaviest build. Generally a commercial floor thickness, for busier traffic and the longest spans.

Every span above assumes domestic or residential loading. That is 1.5 kN/m2 spread with a 2.0 kN concentrated load for an internal domestic floor, and 2.5 kN/m2 spread with a 2.0 kN concentrated load for a balcony deck. Commercial, public and multi-occupancy use carries higher imposed loads, so none of the span figures above carries across to a shop, a bar, an office, a school, a public building or a block of flats. Those have to be checked and designed for their actual use separately, which is a different exercise rather than a thicker guess, and it is why 39mm is listed as a commercial thickness rather than simply a bigger domestic one. Tell us what the building is used for when you send the sizes. The loadings by building use are tabulated in our glass floor building regulations guide. The same conditional applies to every other figure on this page: indicative spans, edge bearing dimensions and slip ratings are typical values for the arrangement described, not a guarantee of performance in your own opening.

Send us the opening size, how the panel will be supported and what will be walking on it, and we will tell you what we would supply. Getting this right at quote stage costs nothing; getting it wrong costs a panel.

Can you put furniture on a glass floor?

We do not recommend standing furniture on floor glass. Chairs and tables are what people ask about, and the answer is the same for both. Floor glass is designed for people walking across it, and furniture loads it in a way walking does not.

The difference is the concentrated load. Somebody on their feet spreads their weight over a reasonable area and keeps moving. A chair leg puts its share of that load through a foot the size of a coin and then leaves it there. That is what the 2.0 kN concentrated load figure is about: it is the worst case the panel is designed against, not an allowance to park a point load anywhere on the glass indefinitely. It is worse again close to an edge or a corner, where glass is at its weakest and where nearly every breakage starts, so a chair in the middle of a panel and a chair with a leg against the glass edge are not the same proposition.

What we will not do is tell you whether a particular chair, on a particular panel, in a particular position, is acceptable. What we publish is the loading the panel is designed to: 1.5 kN/m2 distributed with a 2.0 kN concentrated load for an internal domestic floor, 2.5 kN/m2 distributed with the same 2.0 kN concentrated load for a balcony deck, and higher imposed loads for commercial, public and multi-occupancy floors, which are designed separately. Assessing your own furniture against that figure is your call, your engineer's or your building control body's, because it turns on the weight, the number of legs, the size of the feet, where they land and how often the thing gets moved. If the furniture is heavy, or the panel is already near its limit, that is a question for a structural glass engineer rather than for us.

If furniture is going on the glass anyway, and in practice it often does, two things reduce the harm:

  • Spreader plates under every leg. A plate under the foot turns a point load into a distributed one, which is the whole problem in miniature. The larger the plate, the gentler the load on the glass.
  • Soft neoprene rubber between the plate and the glass. A bare metal or hard plastic foot will scratch glass, and trapped grit does it faster. A soft rubber pad cushions the contact and keeps the surface intact.

We will not give you a plate size or a rubber thickness, because that is the specific advice we have just said we do not give; both are a judgement against the concentrated load figure above. Beyond that, keep legs away from edges and corners, do not drag furniture across the glass, and treat anything on castors the same way, since a wheel concentrates load as a leg does and abrades the surface as it moves.

Sizes, weight and offloading

Our listed sizes run up to 2000 x 1500mm, and we stop there deliberately. Past that size the limiting factor is not really the glass, it is weight and what can sensibly be delivered and lifted into place. A 2000 x 1500mm panel in 39mm is close to 300kg.

Larger panels are made by custom request rather than off a price list. Before we accept an order for one, we will ask you to confirm that you have the people and the equipment to take it off the wagon safely. We do not arrange lifting, craneage or offloading, and we do not quote for it. Send us the sizes and we will price the glass.

If your opening is not a rectangle

Nearly everything listed on this site is square or rectangular, because nearly every opening is. When yours is not, that is a drawing and a template rather than a different product. The glass is cut to profile and the steel frame is fabricated to match it in our own Sheffield workshop, so the outline is not the thing that decides whether we can make it.

D shaped walk-on glass well cover set flush into a herringbone oak floor
A D-shaped cover set flush into a herringbone floor. One straight edge, one curve, and a flat laminated panel cut to the profile.

The glass itself stays flat. What changes is the shape of its outline, not the shape of the pane. A semi-circular or D-shaped cover over an old well, a square panel with one side curved around a spiral stair, a run of angled facets following the line of a staircase: all of those are flat laminated panels with a profiled edge. Glass that is curved in section is a different and far more expensive process, and it is almost never what a floor needs.

Square walk-on glass floor panel with one curved edge worked around a spiral staircase
A square panel with one side curved to clear a spiral stair. The frame follows the same profile.

The rules do not relax for a shaped panel. It still has to be supported continuously all the way round its perimeter, the bearing still has to be level and unbroken including around the curves, and it is still sized on its longest span rather than on its area. A D-shaped cover 1400mm across the straight edge is sized as a 1400mm panel, not as something smaller because there is less glass in it.

Three things are worth knowing before you set the opening out:

  • Sharp external points get radiused. An acute corner is the most vulnerable part of a laminated panel and the first place a chip starts. Where two edges meet at a tight angle we will take the point off, and the drawing will show you by how much.
  • Internal corners matter more than external ones. Where the outline turns back on itself, as it does on an L-shape or a stepped panel, stress concentrates at that internal corner and it is the first place a shaped panel will crack. We radius it rather than leaving it sharp, and on anything of any size we would rather split the shape into two panels with a support on the joint line than cut a single L.
  • Several panels often beat one large shape. An awkward run is frequently easier to make, deliver, lift and replace as a series of panels with an intermediate support between them than as a single piece. It also means that damage later on costs you one panel rather than the whole floor.

Sending us a shape

Dimensions are enough for anything made of straight lines and known radii: give us the sizes and tell us where the curves are and what radius they run to. For anything genuinely irregular, an old well head, brickwork that steps in and out, a stair string that is not quite where the drawing said it would be, a cardboard template taken off the opening itself is the reliable answer and takes about ten minutes. We can work to a template as easily as to a dimension. A CAD file, a DXF or a setting out drawing is equally good if you have one.

Shaped panels and frames are quoted rather than ordered against the size bands, so send us what you have, with photographs and something in shot for scale, and we will tell you what is possible before you commit to any building work.

Slip resistance and non-slip treatment

Glass is slippery underfoot. On anything that will genuinely be walked on we would take the non-slip treatment, and the only case where we would tell you not to bother is a panel tucked in a corner nobody crosses.

Our invisible non-slip treatment is a clear chemical treatment that makes no visible difference to the glass at all. That is the question almost everybody asks before they order, and the answer is that you keep the clarity and the view straight through the panel. It reaches a Pendulum Test Value (PTV) of 68 to 71 dry, against the 36 needed to count as low slip risk, and lasts around five years before it wants redoing.

Wet, the same treated glass comes in around 19 to 23. It is still better than untreated glass, but it does not lift it out of the high slip band, and no chemical treatment will. That does not rule it out of anywhere that gets wet. It means the wet case is a decision rather than an oversight, and the questions worth asking are how often the panel will actually be wet with somebody standing on it, and what happens if they slip. On a landing or a cellar hatch inside a house, usually nothing. On a walkway with a drop beside it, a ramp, or anywhere in public use, the answer should be a physical texture.

Where that is the case, the highest grip comes from a sandblasted chequer plate or etched top surface. We make those to order rather than selling them online, so ask us for a quote. The trade-off is the whole decision: an etched or chequer plate surface visibly obscures the glass, so if the panel is there to be looked through, it changes the thing you bought it for. The invisible treatment does not affect clarity at all. Neither is wrong, but choose with both facts in front of you.

If you already have the glass and only want it treated, or the panel is installed and cannot come out, that is a separate service. Our anti-slip glass treatment page covers it, along with the full wet and dry pendulum figures and what we can and cannot treat.

Painted borders

A painted black border is a band of paint set between the laminated interlayers rather than applied to a face, so it cannot scuff, wear or be cleaned off. It hides where the glass seats and any silicone, fixings or frame edge underneath, which is usually why people want it.

We offer 50mm and up to 100mm as standard options online, and a 50mm border is included as standard on every framed unit. Other widths are available: if you need something specific to suit your frame, bearing or upstand, tell us the width and we will price it. Frosted borders are available in the same way if you want the edge softened rather than blacked out.

Dark colours are the safe choice for a border. You are looking at it through several plies of glass, and a pale colour, white especially, picks up the green cast of the glass and reads slightly tinted. Low iron glass reduces that but does not cure it.

Ritec ClearShield

Ritec ClearShield is a surface treatment applied to the underside of the panel. It leaves a non-stick surface that is easier to keep clean and resists the staining and discolouration that repeated wetting and drying leaves on untreated glass. Ritec also describe the treated surface as anti-microbial, resistant to the adhesion and growth of bacteria, viruses and fungi.

It earns its place where the underside is hard to get at, which on a sealed-in floor panel or well cover is most of the time. Where you can reach both faces easily, it is a convenience rather than a necessity.

Condensation

Where a panel sits between a cool, damp space below and a warmer room above, expect some condensation on the underside. That is normal, it is not specific to glass, and no coating prevents it. How much you get depends on how damp the space below is, how deep it is, and the temperatures either side.

Ventilation is the fix, not a treatment on the glass. ClearShield is not a condensation treatment and we do not sell it as one. Our glass well cover FAQ sets out what drives condensation and what actually deals with it.

Which frame style do you need?

If you would rather not build the frame yourself, we supply the panel complete with a steel frame, made in our Sheffield workshop and UKCA marked to BS EN 1090-2, with the bearing already set out correctly. There are three frame types, and the typical detail drawing (PDF) shows all three sections.

Start with Frame A. It is what most people choose and what we would suggest unless something rules it out, and the only thing that rules it out is not having enough depth of floor to bury it in. Answer that question first and the choice usually makes itself.

  • Frame A sits around and over the opening, so you can tile or floor up to it for a flush, floor level finish. It is self supporting and relies on no fixings at all. The only requirement is that you have enough build-up of flooring to accommodate it, 35 to 40mm minimum, so the glass finishes flush with floor level. Order your hole size plus 100mm.
  • Frame B is what you use when you do not have that build-up, so it is more of a retrofit, with the existing flooring already in place. It drops into the opening and takes its support from the surrounding floor, and there is only a 5mm perimeter ledge to build in. Some people do not build that ledge in, which leaves the frame standing about 5mm proud as a trip ledge, so it is not recommended in a busy walkway. Order your hole size.
  • Frame C bolts inside the opening and lets you raise or lower the height within the aperture as required. It requires the opening to be suitable to fix to, and it relies on fixings entirely, which is why it is the least recommended of the three. Order your hole size.

All three come with seating rubbers to buffer the glass, and silicone sealing is available on frames A and B but not on Frame C, because on Frame C the seal would be made against the fixing surface of the aperture rather than against the frame itself. We would seal it. Left as an open gap it is unsightly and it becomes a dust and moisture trap, and for the occasional maintenance job, cutting the seal out and resealing afterwards, that is manageable. There is more on sealing, and on getting a sealed panel back off, in our glass well cover FAQ.

Choose powdercoated for internal, dry use, or galvanised and powdercoated for external or damp internal use.

If the panel needs to open, that is a fourth type. A hinged glass floor is a drop-in frame with a second, hinged frame inside it carrying the glass, so the panel lifts for access to whatever is underneath. It is a different product rather than an option on frames A, B or C, because the hinge side, the gas struts or motor, and the clearances all have to be designed in. See our hinged glass floor framework and the hinged glass floor and wine cellar door FAQ.

Framed units are listed by thickness: 25.5mm, 31.5mm and 33mm. For round openings and light wells, see our glass well covers.

How to order

Each floor glass listing has a drop down of size bands. Pick the next band up from your own panel, so the band is equal to or larger than your glass in both directions, then send us your exact sizes. Remember that the glass size is the clear opening plus the bearing on each side, not the clear opening itself. We confirm your sizes back to you before anything is made. Non-slip and border or coating options are chosen on the same page, so the price you see is the price for the panel as you want it, including VAT.

If your size falls outside the list, or you are working to a date, ask us.

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