01Wet glass
Plain glass is slick, and a walk-on rooflight should not be plain
Smooth glass with a film of rain on it is a poor thing to put a foot on, so the question is really about the surface the maker gives it.
Ask whether a walk-on rooflight is slippery and the honest answer depends on what is on top of the glass. A flat, polished pane with no treatment gets slick when it is wet, and slicker still when a thin layer of algae or frost sits on it. Nobody should be asked to walk across that. A walk-on rooflight made properly does not leave the top surface plain. The upper layer of glass is given a finish that grips, and it is specified for the place it is going to sit.
There are two broad ways to do that, and both are done at the factory, not on your roof. The first is a fritted finish: a ceramic pattern, often small dots or a fine grid, is printed onto the glass and then fired in, so it becomes part of the surface. The second is an etched finish, where the surface is treated with acid so it becomes slightly rough, a bit like the frosting on a bathroom window. Either way, the foot meets something with texture instead of a bare sheet.
Indoors, under a stair or in a hallway floor, the risk is low and the treatment can be light. Outdoors, on a patio, a terrace or a path beside the house, rain, leaves and winter damp are all part of the job, so the finish needs to be properly coarse.
Fritted finish
A ceramic pattern fired onto the glass. It can be dense or open, so the maker can tune the grip, and it also softens glare and the see-through effect from above.
Etched finish
The surface is roughened with acid. It gives an even, frosted look with no pattern to line up, and it suits spots where you want a soft, uniform appearance.
02Grip
How grip is judged, and what to ask for
Slip resistance is something a maker can measure, so you can ask for a rating instead of taking a promise.
Floor surfaces are commonly tested with a pendulum, a swinging rubber foot that drags across the surface while wet, and the result is given as a number. A higher number means more grip. You do not need to become an expert in the test. What matters is that the maker states a slip rating for the finish on your particular glass, and that the rating suits where it will be used. A finish that is fine for a dry indoor floor is not automatically right for an exposed patio.
We do not invent a figure for you here, because the number belongs to the product and the finish chosen. At survey we go through the options with you and put the maker's stated rating in the written quote, so you can see it before you agree anything.
Walk-on glass is laminated, built up from several layers, because it has to carry a person. The grip finish is a separate decision about comfort and safety underfoot, made on top of that.
- A fritted or etched top surface, not plain polished glass
- A slip rating stated by the maker for that finish
- A finish matched to indoor or outdoor use
- The maker's cleaning advice for that finish, written down
03Outdoors
What changes when the glass is outside
Weather, leaves and shade all work against grip, so an outdoor walk-on rooflight needs a bit more thought than an indoor one.
Think about a patio at the back of a south Essex semi, where a rooflight lights a basement room or a utility space below. In dry July it is a lovely warm panel to cross. In a wet November it is covered in fallen leaves, and in a shaded corner a green film of algae can build up over a season. Frost on a still January morning is another worry. Any of these can make a smooth surface treacherous and will make even a good finish less grippy than it was new.
That is why placement counts. A rooflight in the middle of the main route to the back door is asking for more from its finish than one tucked at the edge of a seating area. If the glass will be a regular stepping place, tell the maker and ask for the coarser option. If it is mainly there to bring light down, a lighter finish may do and you can steer feet away from it by laying the paving to suit.
Drainage helps as well. A rooflight set slightly proud of the paving, or surrounded by a surface that falls away from it, sheds standing water instead of holding a puddle. We look at how glass sits in a patio on the page about putting a walk-on rooflight in a patio.
04Upkeep
Keeping the grip you started with
A textured finish only works while the texture is clean, so a little regular care is part of the deal.
Grime, moss and dried-on dirt sit in the tiny hollows of a fritted or etched surface and fill them, which is exactly where the grip comes from. Wash the glass with warm water and a soft brush, then rinse. Skip harsh abrasives and anything the maker warns against, because scratching or polishing a finish can change how it behaves. If the maker has supplied cleaning advice, follow it to the letter.
The glass is also only one part of the story. A rooflight that has been specified for warmth, with an insulated unit under the walking layer, behaves better in cold weather because the whole build holds its temperature better. We cover how insulation fits into a walk-on unit on the page about whether walk-on rooflights are insulated, and the finish options in more depth in our guide to anti-slip walk-on glass.
- Sweep off leaves and loose grit before it is trodden in.
- Wash with warm water and a soft brush or cloth.
- Rinse well so no film of cleaner is left to dry on the surface.
- Treat green algae early, with a product the maker says is safe for the finish.
If you are planning a skylight you can walk on, the place to begin is the main page on walk-on rooflights. When you are ready, a free survey and written quote from Radiant Skylights will settle the finish, the rating and the position before any work starts.
How safe is it underfoot when the glass is wet or frosty?
Can I walk on a walk-on rooflight in bare feet or socks?
Indoors, on a clean dry finish, people do, and the finish is chosen with that in mind. Outdoors in wet weather it is better to wear shoes with some tread. Check the maker's stated slip rating for the finish you choose.
Will an anti-slip finish spoil the view through the glass?
It changes it. A fritted or etched surface softens and diffuses what you see, so you get daylight but a less crystal clear picture. A lighter pattern lets more through, a heavier one grips more, and we talk through that trade at survey.
Does the anti-slip finish wear away?
A fired ceramic frit is part of the glass surface, so it is hard wearing, but any finish needs sensible cleaning. Heavy abrasives and harsh chemicals can change how a surface behaves, so follow the maker's advice.
Is walk-on glass safer than ordinary glazing to stand on?
It is the only kind that should be stood on. It is laminated from several toughened layers and built to a stated load. Ordinary glazing is not made to take a person and must never be walked on.
