Are Walk-On Rooflights Slippery?

Why clear glass would be a poor floor

Ordinary glass is smooth to the point of being polished. A damp sole on a bare pane has very little to hold on to, which is why nobody would want a plain window set into a landing or a terrace. The makers of walk-on units know this, so the walking face is never left as it came off the float line. Texture is added on purpose, and it is part of what the product is.

The aim is a surface that you can cross in socks, trainers or garden shoes without thinking about it. It cannot be as coarse as a paving slab, because you still need to look down through it. The finishes below are the compromise that works.

How the grip is made

There are two common finishes, and each is applied to the top layer before the unit is assembled.

• With fired ceramic dots, a pattern of tiny enamel dots is printed on the glass and baked into it in the toughening oven. The dots stand up from the surface and give the sole something to bite on. Between them the glass stays clear.
• With acid etching, the surface is lightly eaten away so it becomes finely rough and frosted. The texture is even across the whole pane, and the look is softer.

Both are part of the glass, not a coating that wears off. You cannot peel a dot pattern away or scrub an etch out, so the grip is there for the life of the unit.

Choosing a walking finish

Dot pattern	Clearest view through, most obvious texture underfoot
Acid etch	Frosted look, even texture, hides some marks
Best indoors	Either; choose by the look you want from below
Best outdoors	Dots, where wet weather and dirt are a regular thing

What it feels like when wet

Rain on a dotted surface sits in the gaps between the dots, and the dots themselves stay proud of the film. A shoe usually feels secure on it straight away. An etched pane holds a thin layer of water in its texture, and it also grips, though it can feel a little smoother than the dots when truly soaked.

Compare it with a good stone terrace rather than a wet bathroom floor. Walk-on glass will not be quite as grippy as rough stone, so we would not put it on a steep slope or at the top of steps without a different plan.

Algae, leaves and frost outdoors

Outdoors is the harder test for any walking surface. A shaded terrace collects a green film in the damp months, and it forms first in the corners that never dry. Wet leaves sit flat on glass and a thin skin of ice is invisible against it.

None of that is peculiar to glass. A mossy paving slab is just as dangerous. The answer is the same for both, which is to keep an eye on it:

• Sweep leaves and grit off before they are trodden in.
• Wash the surface when you wash the terrace, and rinse off any cleaner.
• Treat frost as you would on any other walking surface, and take care first thing in the morning.

A dotted pane that has been polished with a silicone cleaner will grip worse than one left alone.

From a survey in Dringhouses

Where we would think twice

Most homes are fine. A few situations need talking through at the survey. A pane on a slope, a surface right beside a pond or hot tub, a doorway that gets wet feet and a spot where a child will run all raise the question of whether glass is the right surface. Sometimes the answer is to move the glass to a drier part of the terrace, or to choose a finish with the stronger texture.

Because every unit is made to order, the finish is chosen with you before anything is manufactured. Sample squares come with us on the visit, so a hand and a shoe can test them in place of a photograph.

Shoes, socks and bare feet

Footwear changes the answer a good deal. Rubber soles grip a dotted face very well. Leather soles and smooth-bottomed slippers are less sure on any wet surface, glass included. Bare feet feel the texture directly, and some people find a dotted finish a little knobbly at first, while an etched pane feels like fine sandpaper. If children will play barefoot on a terrace, say so, because it nudges the choice towards the gentler etch.

Pets are a small consideration too. Claws click on glass, and a dog may hesitate at first on a see-through surface. Most settle in a day or two.

Where to read next

Grip is one part of living with a floor you can see through. The wider picture is in our walk-on rooflight installation page. If you are wondering what the glass is built to carry, see how thick walk-on glass is. For a terrace project, walk-on rooflights for roof terraces covers the outdoor conditions in more detail.