Atrium roofs get found out in winter. The defects are there all year, but a dry August hides them, and then the first sustained period of wind-driven rain pushes water through something that had been coping.
Autumn is the window for doing something about it, and most of the useful checks don’t need a contractor on site to start with.
Clear the drainage, and clear it properly
Blocked outlets cause more winter leaks than failed glass does. An atrium roof is usually flat or shallow, so it relies entirely on gutters, channels and outlets to shed water, and every one of those fills up over a year.
Leaf litter is the obvious culprit on a site with trees nearby. Silt is the one people forget: dust and grit settle out of standing water, consolidate, and end up as a firm layer that water runs over rather than through.
Weep holes in the glazing framework need the same attention. They’re small, they block with grime and insect debris, and when they do, water that got into the system has nowhere to go but inwards. Clearing them is a few minutes of work at close access and it prevents a category of leak entirely.
Check what happens downstream too. An outlet that’s clear at the top and blocked ten metres down the pipe looks fine from the roof and backs up in the first heavy rain.
Look at the roof a few hours after rain
Standing water is a drainage defect telling on itself. Anywhere holding water once the rain has stopped is either not falling towards an outlet or not reaching one, and in winter that puddle freezes.
Ice does two things. It expands, so it works on seals and gaskets with real force. And it weighs more than nobody planned for, because a frozen pond on a shallow roof is a load the structure was sized for as snow, not as an additional permanent lake.
A photograph of where the water sits, taken in October, is worth more than a description in January.
Perimeter seals and gaskets, at close access
The joint around the edge of a glazed roof absorbs the movement between the glazing and the structure, and it’s a consumable with a working life.
What to look for: sealant that’s gone hard rather than staying rubbery, splits along the bead, sections pulled away from one face, gaps opening at corners. Gaskets that have shrunk back from the ends of a glazing bar leave a direct path for water under wind pressure.
Corners first, because that’s where the movement concentrates and where failure starts.
This is a job for someone next to the roof rather than looking at it from the floor, and that access planning sits under the work at height requirements whoever carries it out.
Count the misted units now, not in February
A unit that has lost its edge seal mists in cold weather and clears as the day warms. That makes autumn and early winter the easiest time of year to spot them, and the hardest time to spot them is the middle of summer.
Walk the floor on a cold morning and count. The number matters more than any individual pane, because sealed units on one roof age together, and a rising count is the signal that a replacement programme is coming rather than another one-off repair.
The things that are not glass
Two items belong on the same autumn visit.
Smoke vents and automatic opening vents in an atrium roof are part of the building’s fire strategy, and they’re mechanical. Winter is when the actuators and hinges are least forgiving, and a vent that hasn’t been tested since the last one is a vent nobody can rely on. Test it while the weather is mild.
Fixings and capping are the other. Cold cycles and wind loading loosen things, and a cap that has lifted at one end in November is off by February. Someone at close access can see that in minutes.
Where it goes from here
The Centre for Window and Cladding Technology publishes guidance on inspection and maintenance of glazed envelopes, which is a reasonable basis for what an autumn visit should cover and what gets recorded.
Several of these items overlap with the warning signs an atrium gives from floor level, and the overlap is useful: anyone can do the floor-level pass in October and decide from that whether the close-access visit is urgent.
Thermal performance is worth a thought at the same time, since an atrium roof is the top of a tall space and a failed perimeter joint leaks warm air all winter. How glazing products affect energy efficiency on commercial projects covers the specification side of that.
Of everything above, the drainage clear-out is the one to book first. It’s the cheapest item on the list, it needs no design and no engineer, and it removes the most common cause of the call-outs that arrive at four in the afternoon in January. Specialists in high-level work, including skyaccessglazing.co.uk, can combine it with the seal inspection and the vent test so the building pays for one mobilisation rather than three.
