Start with the room underneath
A skylight in paving only earns its keep if it lights something. Typical cases: a cellar below a patio, a store tucked under a raised terrace, a passage beside an extension with a windowless room next to it. The ground above that room is often the only surface open to the sky, and people already walk on it. Glass there lets daylight fall into a space that never had any.
Where solid earth lies beneath the slabs and nothing needs lighting, there is nowhere for the light to go. That makes the room below the first question, and the paving above the second.
The third question is what carries the opening. A slab bedded on the ground is one job. A suspended slab or a deck that spans a void is another. Over a void, the joists, beams or slab edges that cross the hole are picked up and their weight routed around it. On solid ground, the frame normally rests on a new upstand or ledge built round the opening. In both cases the frame is carried by the structure, never by the paving, and the whole route from glass to ground is worked out before a slab is lifted.
That is why we open things up at survey. Patios hide old drains, forgotten beams and levels that look flat from above. We would rather meet them before the quote than after. The main page on walk-on rooflights in Leicester gives the wider picture.
Rain, drains and frost
A path is outdoors, so the unit sits through downpours, leaf fall and freezing nights. Three details keep it behaving.
Where rain goes. The glass is flush with the surface, so water lands on it and has to run away. A gentle fall in the surrounding paving sends it clear of the frame rather than toward it. The perimeter is sealed so nothing creeps beneath. Under the unit, the structure is waterproofed like a small flat roof, because that is what it is. The reasoning matches our page on kerbs and upstands.
Where paving stops. Slabs laid hard against the frame can pin water there. A narrow flexible joint, sealed at the top, keeps grit and weeds out and lets the structure shift slightly through the seasons. A rigid mortar line tight to the glass is the first thing to crack.
Frost. Glass cools faster than stone, so it frosts first. The grip surface helps, but give it the same care as an icy step, and keep the route to the door clear.
Misting is the flip side. A cold pane over a warm room can steam up underneath. The build-up of the glass and the way the room is used decide how often, and we talk it through at survey.
Levels, grip and the edge
The top of the glass should finish at the same height as the paving round it. A lip catches toes and a dip holds puddles. We set out the finished level before the frame goes in, so the surround can be relaid or brought up to match.
Bare glass is slippery when wet, so units in a path or patio get a grip surface on the upper pane. Etched, dotted and gritted types exist, with different looks. Our short piece on slip resistance in walk-on rooflights explains the choice.
Size is a design choice. On a narrow path, a small unit with paving on both sides leaves a dry, textured line to walk along, whereas a pane the full width puts every step on glass. On a patio, the glass can anchor the layout with furniture arranged around it. A heavy table leg or planter loads a single point, which is one of the things we ask about.
So the order is: room below, structure, water, levels, then finish. Begin with the glass and work backward, and you get something that looks good on paper and fights the garden.
Who and what will stand on it
A patio hosts gatherings. Chairs, a table, a grill and guests may all end up on one spot. A walk-on unit is rated for a stated load, and we choose the rating from the way the space is used, not the lowest figure that would scrape through.
Tell us what the patio is for. A bench in a quiet corner is one case. A place where people stand with drinks is another. A path with a wheelbarrow is a third. We record each at survey and match the layers of glass to the answer. The mechanics are in our guide to walk-on glass and loads.
Think about furniture moves as well. A sofa carried through a garden, a skip dropped on a drive or a ladder set down hard are all point loads, and they happen once in a while rather than every day. Mentioning them at survey costs nothing and lets the glass be chosen with a margin.
Vehicles are a different matter. A drive or a path that a car crosses needs its own design, so it is raised with the maker before we talk about a price.
Permission and the next step
A flush unit in paving is not a projection from a roof slope, so the usual roof limits sit differently. A listed building still needs consent before anything is cut. Flats and maisonettes do not carry householder rights, and a conservation area or Article 4 direction can alter the position. The condensed version lives in our skylight planning guide.
If the job needs a Building Control notification, we send it in.
The survey costs nothing and comes before any figures. We open the ground, check what lies below and write the support, drainage, finished level and grip surface into a fixed written quote. Start here: book a free survey.