Walk-on rooflights in Maidstone
Some of the darkest rooms in a Maidstone house sit under a terrace, a paved lightwell or a solid hall floor. Walk-on glass lets daylight down through a surface you can still stand on, and we survey, quote and fit it across the town and mid-Kent.
- Free survey, fixed written quote
- 10-year workmanship guarantee
The long read
Walk-on rooflights: glass for floors, terraces and lightwells
Walk-on glass solves a narrow problem well: a room has solid ground or a used roof directly above it, and the only daylight is straight overhead. The unit has to carry people, shed rain, keep heat in and stay grippy underfoot, so each one is specified for its load and made to measure. To talk through a walk-on rooflight for your own house, get in touch.
Where glass underfoot suits a house
Look for the rooms with a solid lid. A cellar under a hall has no window, because the wall that would hold one is below ground. A utility tucked into a side return is boxed in by a neighbour's brickwork on one side and the house on the other. A basement room reached from the old coal store has a lightwell outside it, but the lightwell is paved over so the garden can use the space. In each case the only direction left for daylight is down from above, and the surface above is somewhere people want to step.
That is what a walk-on rooflight is for. It is a glazed unit set into a floor, a terrace or a flat roof, built to take a person's weight, and it lets daylight pass through to the room beneath. Skylights that are called walkable sit in this family, and our short answer on whether you can walk on a skylight covers what separates them from an ordinary unit.
Terms for glass underfoot
- Walk-on rooflight
- A laminated glass unit set flush or on a low kerb, designed to carry people standing or walking on it.
- Lightwell
- A sunken space outside a basement wall that lets daylight reach the room beside it.
- Flush glazing
- Glass whose top surface sits level, or very nearly level, with the paving or roof around it.
- Imposed load
- The weight a floor or roof is designed to carry from people, furniture and use.
Roof terraces and flat roofs
A flat roof over a ground-floor extension makes a good terrace when the first-floor landing window opens onto it. The room below, though, loses what little light it had, because a decked or paved terrace blocks the sky. A walk-on unit set in the terrace puts a pane of daylight back into the ceiling below. The room beneath such a terrace may be an orangery-style garden room, a study or the middle of a kitchen that the side windows already light as far as they will go.
Basements, cellars and lightwells
A cellar that has been converted into a playroom or a gym still needs daylight, and a window-sized slot of glass in the floor above makes a difference you notice the moment you go down the stairs. Where a lightwell exists, a walk-on cover over it keeps the garden or path usable. Where it does not, the glass can go in the hall or garden floor directly above the room. Either way, the ceiling height of the room below, the depth of the floor build-up and the position of the joists decide what can be done, and we work that out on site.
Landings, galleries and internal floors
Inside the house, a glass panel in a first-floor landing or mezzanine lets light from a roof window fall through to the hall below. This is the one place where the unit is treated as a floor, and the structure beneath it has to be designed for foot traffic and for the fixings the panel needs.
Where a different product is the better answer
If nobody will ever step on the roof, a standard unit is simpler. A flat roof rooflight or a roof lantern costs less and has a shorter list of conditions. If the roof is pitched, a roof window, such as a VELUX unit from our roof window range, is the correct choice, since a slope is not a walking surface. A narrow dark hall with a loft above is a job for a sun tunnel. Walk-on glass is for places where the surface above has to remain a floor, in residential homes of every age.
How walk-on glass is built
A standard double-glazed rooflight is designed to keep out weather and hold its own weight. Walk-on glass has a harder job. We specify laminated build-ups, where several layers of strengthened glass are bonded together with clear interlayers. If one layer cracks, the others and the interlayer keep the unit together so it does not drop out of its frame, and that is the main safety idea behind every walkable unit.
| Question about the use | What it sets | Where it is settled |
|---|---|---|
| Who and what will stand on it | The load the unit is designed for | Survey, then manufacturer and engineer |
| How wide and long the opening is | The build-up and weight of the glass | Our measure of the opening |
| Rain, shade and algae outdoors | The anti-slip finish on the top face | Sample held up at the survey |
| Heat on the room below | Glazing type, coatings and gap | Written on the quote |
Load ratings
Every walk-on unit is designed for a stated imposed load. A private terrace used by two people for coffee is a different job from a courtyard where a table, chairs and a barbecue stand, and a glass hallway floor takes different loading again. The rating is a design decision for the structure and the glass together, not a label on a catalogue page. We ask how the surface will be used, then pass the details to the manufacturer and the engineer, and the figure that results goes onto your quote. Our guide to walk-on glass loads and structure goes further into how ratings are worked out.
Thickness and weight
The finished unit is thick. A build-up of several panes plus interlayers makes a slab you can feel in your hands, and the thickness depends on how far the glass spans between its supports as well as on the load. A small square unit can be slimmer than a long rectangle on the same load. Because the glass is heavy, lifting gear and a couple of installers are needed on the day, and the opening is sized for the weight. We explain the reasoning in how thick walk-on glass is.
Anti-slip surfaces
Wet glass is slippery, so the top face carries an anti-slip finish. Typical treatments include a fired pattern of small ceramic dots, an etched texture or a sandblasted band, and each leaves the glass translucent or clear in a different measure. A finer pattern gives a clearer view of the sky and a less grippy surface; a heavier pattern grips better and diffuses the light. On a terrace that gets rain and algae, we lean towards a coarser finish. Over a hall floor that stays dry, a lighter pattern is a sensible choice. You see a sample of each at the survey and hold it against the room.
Glazing for heat
A walk-on unit that sits in the roof or in a ground-floor slab between the weather and a warm room is also part of the insulation. Double glazing is built into the unit, with a coating and a sealed gap, and triple glazing can go in where the structure carries it. The glass unit and its frame together have to meet the limit for rooflights, which we return to in the chapter on the rules.
Aluminium frames
The frame that holds the glass has to keep its shape under load and under heat from the sun. Aluminium frames are the usual choice for a walk-on unit because they are rigid and slim, and they take a powder-coated finish in a colour that suits the paving. We specify the frame as part of the made-to-measure unit, working from the manufacturer's range for the load, and do not use bulky uPVC sections for a load-bearing job.
What holds the glass up
Glass that carries weight puts that weight on whatever is around it. Before the first sheet is ordered, the question is always what is underneath and beside the opening. A roof joist, a steel beam, a concrete slab, a brick wall and a timber floor take a point load in different ways, and the glass supplier will want to know which one it is.
Survey notes before glass is ordered
- Open the ceiling above Check the joists, beams or slab that will carry the opening.
- Record the finished surface Note the paving, membrane or boards around the glass.
- Measure the opening Check width, length, square and level, and the depth of the build-up.
- Plan the lift Find the route the glass will take to the opening.
- Pass the load to the engineer Give the use and the span for a structural check where one is needed.
Cutting into a roof or floor
A new opening cuts through whatever carried the surface. In a flat roof, that means joists. In a ground-floor slab, it can mean reinforcement. The cut sides then need trimmers or a beam, sized by calculation, so the loads travel round the opening into the walls. On a new extension the engineer designs this alongside the rest of the structure. On an existing roof or floor we check what is there at the survey, and any strengthening shows on the quote as its own line.
The kerb, or no kerb
Some walk-on units sit on a low kerb, or upstand, which keeps water away from the frame. Others are fitted flush, with the glass almost level with the terrace around it. A flush unit looks neater and has no step to trip on, but it asks more of the waterproofing and drainage around it, since rain has no height to run off. A kerb gives you an easier job on a flat roof with a membrane, a flush frame suits paving laid on a base. Which one fits depends on the surface, the falls and the finishes, and we set it out in the specification.
Measuring for glass that cannot be trimmed
You cannot shave a laminated pane on site. A frame and glass made too large will not drop in, and one made too small leaves a gap that has to be sealed over. So the measure takes in the finished opening, checked for square and level, with an allowance for the build-up around it. For an opening in a floor, we also record the depth of the structure so the unit's frame matches. If the opening is not yet cut, we agree dimensions with the builder before it is made.
Getting heavy glass to the opening
The glass unit has to arrive at the place it is fitted. A cellar floor reached through a hall needs a path for panes that are heavy and awkward; a roof terrace over a first-floor extension needs a lift from the garden or a crane. We note the access at the survey, because it affects the number of people, the equipment and the quote.
Daylight and heat through a floor of glass
A room under a terrace usually has the opposite problem from a conservatory. It gets too little light and holds its heat. The glass above is a small proportion of the surface of the roof, so what it delivers depends on its size, the finish on its top face and the sky above the house.
Myth
Glass you can walk on must be dim and cloudy.
Fact
A fine pattern on the top face lets sky through, and the glass beneath can be clear or tinted to suit the room.
How much light comes through
Anti-slip patterns scatter light, so a patterned unit gives a softer glow than clear glass. The room below sees a bright, even patch where a plain unit would show a hard-edged beam moving across the floor with the sun. A basement room suits that gentler light, since there is no daylight from anywhere else to compete with it. Position matters too. A unit placed over the centre of the room spreads light around, and one pushed against a wall lights that wall and leaves the far side dim.
Surrounding structures change the result. A high boundary wall, a first-floor bay or a neighbouring extension throws shade across a terrace for part of the day. We look at the sky above the opening on site, because the unit works with the sky it can see.
Keeping the room comfortable
Glass in a sunny roof can warm the room below in summer. Solar control coatings reflect part of that heat while letting daylight through, and they are an option on a south- or west-facing terrace over a living space. Over a cellar or a north-facing basement, clear glazing keeps the room bright with no risk of overheating, and the stable ground temperature around the walls helps. A sealed, double-glazed unit with a low-emissivity coating limits winter heat loss. You will find more on glazing performance in our guide to energy-efficient rooflights.
Condensation and misting
Glass that sits between a cold surface and a warm room can attract condensation on the room side. A thermally broken frame and a well-insulated kerb or build-up around the edges keep the glass edge warmer, and ventilation in the room below does the rest. If the sealed unit itself ever mists between the panes, that points to a failed seal, and our page on misted rooflights explains how replacement works.
Cleaning and dirt on a used surface
A terrace unit collects leaves, grit and footprints. Rinse it with water and a soft brush, and keep the drainage outlets nearby clear. Strong abrasives scratch the top face, and in an exposed courtyard, a coarser anti-slip finish hides marks better than a fine one. We give you care notes with the handover.
Security and privacy
A laminated build-up resists being broken through, and fixings that sit inside the structure limit tampering. Privacy matters for a unit in a landing or a hall floor: a patterned or frosted top face stops people seeing down into the room below, and a clear unit does not. The choice is yours, and we show samples of both.
Planning, Building Regulations and safety
A glass floor is both a rooflight and a place people stand, so more than one set of rules bears on it. The questions are whether the council needs to be asked, whether the structure and the glazing meet the regulations, and whether the surface is safe to use.
Papers to have to hand
The planning history of the house, any drawings of the terrace or floor, and any Building Control certificate from earlier work on the same roof.
Planning permission for a terrace unit
For an ordinary rooflight on a house, Class C of permitted development usually applies and caps how far the frame may stand above the original roof plane, with further conditions that our skylight planning guide sets out in full. A flush walk-on unit sits close to that plane, but the planning picture for a flat roof used as a terrace is wider than the glass alone. Using the roof as a terrace, adding a balustrade for it or altering a listed or conservation-area house can each raise a separate question. A flat, a maisonette or a house created by a change-of-use permitted development conversion has no householder permitted development rights at all. We check the position for your address at the survey.
Building Regulations
Forming a new opening in a roof or floor is building work. Structure comes first: the trimmers, beams and bearings must carry the glass and the people on it. Energy comes next, and a rooflight in an existing dwelling has a maximum U-value of 2.2 W/m²K in Part L, assessed for the whole unit with its frame. Then there is protection from falling: where a terrace is open at the edge, the guarding comes under Approved Document K. For notifiable work the Building Control notification is ours to make, and inspection and sign-off sit with the council or a registered approver. Our short answer on whether walk-on rooflights need Building Regulations goes through the parts one at a time, and the skylight Building Regulations guide covers rooflights in general.
| Part of the job | Rule that looks at it |
|---|---|
| Size and look of the unit on the roof | Planning, Class C where it applies |
| Beams, trimmers and bearings | Building Regulations, structure |
| Glazing and frame heat loss | Part L, rooflight limit |
| Open edge of a terrace | Approved Document K, protection from falling |
Fire and the roof covering
The roof surface around a house has requirements for resisting fire spreading from a neighbouring building, set out in Approved Document B, and glazing in a roof has to be considered in that context. If the terrace sits close to a boundary, the position of the glass relative to that boundary can change what is acceptable. We check the distances on site and specify accordingly.
Slip resistance and edges
A terrace unit needs a surface that grips when wet, and the anti-slip finish covers that. The edge of the frame also matters, since a raised lip is a trip hazard and a flush frame removes it. For a roof terrace the guarding at the open edge protects people from the drop, and the glass unit itself must not be the only thing between a person and the room below unless it has been designed for that role.
Listed and conservation-area houses
Sitting inside a conservation area leaves Class C in place unless an Article 4 direction has taken it away. A listed house is different, and a new or altered opening in the roof will almost always need listed building consent. Our conservation rooflights pages cover both. For national guidance, see the Planning Portal.
What moves the price of walk-on glass
A walk-on rooflight costs more than a standard flat rooflight of the same width, because the glass is thicker, the frame is heavier and the structure underneath is designed to carry it. How much more depends on the job. We do not give a price off a photo, and the published guide to what a walk-on rooflight costs explains each driver in the order a quote lists it.
Size and span
Opening dimensions drive the glass. A bigger pane needs a thicker build-up and a stronger frame to span the gap, and the weight of the finished unit rises with it. Two smaller units can sometimes be cheaper and easier to lift than one large one, with a structural bar between them, but they break up the view and add a joint to waterproof.
The load it carries
A unit for occasional foot traffic is a lighter specification than one that has to take furniture and groups of people. The use you describe at the survey sets the load, and the load sets the thickness. Tell us what will happen on the surface, even if it is a barbecue in July, because specifying later is much harder than specifying up front.
Finish and frame
The anti-slip pattern, any solar control coating and the colour of the aluminium frames each add a line. A frame made to match existing windows can need a custom powder-coat. Flush fitting takes more careful detailing around the edge than a kerb does.
Structure and access
A floor or flat roof that needs new beams costs more to prepare. A route to the opening that can be walked carries less cost than one that needs a crane. Removal of an existing rooflight or a terrace covering, and making good afterwards, also go onto the quote.
What the written quote contains
After the free survey you receive a fixed written quote. It names the unit, its size and load rating, the glass build-up, the anti-slip finish, the frame, the structural work, the waterproofing and the inside finishes, plus the Building Control notification where the work is notifiable. Ten years of workmanship are guaranteed in writing. For the whole range, our costs page lines up every product.
What the walk-on quote adds up
- Glass and load ratingBuild-up, thickness and the load the unit is designed for.
- Frame and finishAluminium section, colour, kerb or flush detail and anti-slip pattern.
- Opening and structureTrimmers, beams or slab work and the waterproofing around the edge.
- Access and liftingThe route to the opening and the equipment needed to land the glass.
- Making goodInside reveals, plaster and paint, and the outside surface around the unit.
Fitting day, and how to book a survey
Walk-on units arrive made to the measure we took, and fitting day is mostly about getting the opening ready and landing the glass without a knock. When the opening is prepared the work is quick; the preparation is what takes the time.
The sequence on site
We protect the room below and the area around the opening first. Next comes the cutting, with trimmers or beams fitted where the design needs them, followed by the kerb or the flush bearing surface. The frame is fixed and sealed, the glass is lifted into place by the team and checked for level, and the waterproofing is dressed to meet it. Inside, the reveals are boarded and finished to take plaster and paint. If a roof or floor has to be reinstated around the unit, that happens before we leave.
After the work
Building Control signs off the job through the local authority or a registered approver, and you keep the completion paperwork with the deeds. Our 10-year workmanship guarantee comes in writing. We cover installation and replacement of every product on the site, so a later change is a conversation with the same firm.
Where we work
Our base is Maidstone, and the areas covered stretch about 30 road miles around it. Close in, that includes Bearsted, Coxheath, Aylesford and Larkfield, and out towards Kings Hill, the Medway towns and the Weald. Each borough has its own planning team, and we check the records for your address.
Starting with a message
Use the quote form, or send photos and a rough sketch of the room and the terrace or floor above it on WhatsApp, 07880 284133. Email works too: info@orchardskylightsmaidstone.co.uk. Tell us what is above the dark room, what you would like to do with that surface, and whether the house is a flat, listed or in a conservation area.
A room under an unbuilt extension is easiest, because the opening can be formed with the structure. A cellar or lightwell calls for a visit to see the floor above. A replacement of an old walk-on unit starts with the existing frame. For any of them, use the quote form.
Walk-on rooflight guides and answers
Glass floors, terraces and lightwells
Who decides whether my flat roof can carry walk-on glass?
The structure decides, and we establish what it is at the survey. Where the joists or slab need checking, an engineer's calculation is done before the price is fixed, and any strengthening shows as its own line on the written quote.
How is the glass kept from being slippery in rain?
The top face carries an anti-slip finish, such as a fired dot pattern or an etched texture. A coarser pattern grips better outdoors; a finer one suits a dry hall floor. You hold samples against the room at the survey.
We have a cellar under the hall. Could glass in the floor light it?
Often a pane in the hall floor can, provided the floor structure allows an opening and the cellar ceiling is high enough for the frame depth.
Can a table and chairs stand on a roof terrace rooflight?
That depends on the load the unit is specified for. A unit designed for occasional steps is a different build from one that carries furniture, so tell us how you plan to use the terrace and we specify to match.
What should I send before you visit a lightwell?
Photos of the lightwell from above and of the room beside it, plus the rough size of the opening. The photos help us bring the right kit, and the visit does the measuring.
Book your free survey
Tell us about the room that stays dark. We come out, look at the room and the roof, then send a fixed written quote.
Or on 07880 284133, or call 01622 277162
No obligation. We survey before we price.