Do you remove the old rooflight and dispose of it?

What comes off a flat roof, and how much of the kerb goes with it

A flat roof replacement takes a different pile down. The unit itself, whether that is a flush glazed rooflight or a twin-skin acrylic dome and its base frame, plus the retaining trim, the fixings and the sealing tape under the flange.

Then the question of the kerb. Where it is treated, insulated on its outer face and correctly weathered with the covering dressed up and over, it stays and carries the new unit. Where it turns out to be untreated softwood with the felt turned up but not over, which is what commonly appears under a 1980s extension dome, it comes off and is rebuilt, and the old timber goes in the skip along with the strip of covering that was dressed to it. The waterproofing around the opening is cut back to sound material and the offcut leaves site with everything else. What decides between the two is set out at reusing an existing kerb and when not to.

Taking a failed glazed unit down in one piece

Glass is the part of the load that gets planned rather than improvised. A misted but intact sealed unit is heavy and awkward but it is stable: it comes out of the sash or off the kerb, goes onto the platform, and is lowered rather than carried down a ladder.

The units that need more care are the ones that have already lost their integrity. A cracked pane, a dome that has gone brittle enough to break as the retaining trim is unscrewed, or a 1980s sash whose glass is loose in a perished bead. Those are taped across their face before they are moved, taken down in a controlled way, and bagged or crated on the platform. Nothing sharp travels down open, and nothing is dropped off a roof onto a garden, which is worth stating because it still happens.

The covering that is salvaged rather than skipped

A good proportion of what comes off a pitched roof is not waste at all, and treating it as waste is a mistake that shows for the next fifty years. Slates and tiles lifted around the opening are stacked on the platform in the order they came off and re-laid into the new flashing kit.

That matters most on Cotswold stone slate. The courses are graded and laid in diminishing sizes up the slope, so a salvaged slate is not interchangeable with the one two courses above it. Slates are set down by course, and any that break are replaced with reclaimed stone matched for thickness and weathering colour rather than new, because new stone stands out against a two hundred year old roof for a decade. Sourcing that reclaimed material takes weeks and it is arranged before the covering comes off. The same principle applies more mildly to handmade clay plain tiles in the vale and to Welsh slate through the Forest of Dean, where old slates are brittle at the nail holes and breakage rates are simply higher.

Sheeting and materials that get identified before anything is lifted

Some older openings sit in materials that need identifying first, and this is settled at survey rather than on the day. Corrugated cement sheeting on a garage, an outbuilding or a 1960s flat roof, cement based flue or soffit boards near an opening, and certain older bitumen products can all be of an age where testing is the right step before anything is disturbed.

Where a sample confirms it, the removal of that material is arranged with a specialist contractor and it happens first, as its own separately programmed operation, with the rooflight work following once the area is cleared and cleaned. That changes the sequence and the timescale, so it is flagged in the survey notes and priced openly rather than found halfway through a Tuesday. It is one of the reasons the survey looks at the whole roof around the opening rather than only at the unit.

Protecting the house while all of it comes down

Removal is the messiest hour of a replacement and most of the protection goes in before it starts. Inside, floors are covered, furniture is moved or sheeted, and the loft hatch is closed and taped while cutting happens, because thirty year old insulation dust travels.

Outside, the ground below the working area is kept clear, the platform is boarded so nothing can roll off, and where the unit sits above a conservatory, a glass canopy or a neighbour’s garden, a protective deck goes in beneath it. On the Stroud valley terraces, where the ground below an elevation is often a shared lane or a flight of steps rather than a garden, that protection and the route the waste takes down are worked out at survey along with the platform, because there is frequently nowhere to put anything. The access side of that is at can you replace a rooflight without scaffolding.

What is left behind, and the paperwork you keep

At the end of the day the covering is back, the roof is closed, the platform is swept, the ground below is cleared and the load has gone. What remains on site is the new unit, the salvaged covering that went back on, and anything you have asked to keep. That last one comes up more than you would think: people want the old cast frame from a Victorian light, a couple of spare reclaimed slates for the future, or the data plate off the old sash.

What you are given at the end is the completion pack: the ten-year workmanship guarantee, the manufacturer’s own warranty for the glass and frame as a separate document, photographs of the opening at each stage so there is a record of the underlay, insulation and flashing detail now buried under the covering, the waste transfer note, and the Building Control completion certificate in your name once the notification is closed out. Keep that last one, because it is what a buyer’s solicitor asks for. What the certificate covers on a replacement is at do replacement rooflights need building regulations.

Severn Skylights Gloucester fits new rooflights and replaces units that have reached the end of their service life, across Gloucester and thirty miles by road. Email info@severnskylightsgloucester.co.uk with a photograph of the unit from outside, one from the room below and the address, and the reply will say what is likely to come off along with it. Pricing is on the costs page.