Most of the emergency calls we take between November and February are not really emergencies. They are small problems that were sitting on the roof in October and went unnoticed until a storm turned them into a leak. Blocked outlets, a lifted edge, a flashing that has worked loose over the summer.
The difference between sorting one of those now and sorting it in the middle of a January downpour is considerable, both in cost and in how much water has got into your building in the meantime. So here is what actually matters over the next few weeks.
Clear the drainage before the leaves drop
This is the single most useful thing on the list. A flat roof relies entirely on its outlets. Block them and the water has nowhere to go except sideways, into the fascia, the wall, or through any detail that was only ever designed to shed water rather than sit in it.
Clear the gutters, clear the outlets, and check the downpipes actually run. Then do it again once the trees nearby have finished dropping. One clearance in September is not enough if you have a big sycamore next door.
Worth saying plainly: a great many "roof leaks" we get called to are perfectly sound roofs with a blocked outlet. It is the cheapest possible thing to fix and the most commonly skipped.
Look along the edges
The middle of a flat roof rarely fails. The edges do. After a summer of the roof heating and cooling every day, joints that were tight in May can have worked loose by September.
- Trims along the eaves: sitting flat, properly bedded, no lifting
- Upstands where the roof meets a wall or parapet: no cracking or gaps at the junction
- Lead flashings: still dressed into the mortar rather than pulled away from it
- Around rooflights, vents and pipes: sealed and undisturbed
You are not looking for anything subtle. Lifted, cracked or visibly separated is what matters. If it looks wrong, it probably is.
Water that sits
A bit of standing water after heavy rain is normal. No flat roof is perfectly level, and a shallow puddle that clears within a day or two is not a fault. What matters is water that is still there most of a week later, or a pond that has visibly deepened compared with last year.
Persistent deep ponding usually means either the falls are not doing their job or the deck beneath has started to sag. Neither improves on its own, and both are much worse to deal with once winter has been loading that area with water and ice for three months. Our post on what to check after summer goes into how to read ponding marks in more detail.
Moss and debris
Moss holds water against the surface and keeps it there. On a GRP roof it will not eat through the laminate, but it does keep parts of the roof permanently damp through the whole winter, and it hides whatever is underneath it from view.
Brush it off rather than blasting it. A pressure washer on a flat roof is a good way to force water under a trim or lift a detail that was otherwise fine. Same goes for scraping at it with anything metal.
Check the ceiling, not just the roof
Some problems show up inside before they show up on top. Go into the rooms under the flat roof and look at the ceilings: fresh brown or yellow rings, a patch that feels cool or damp, a musty smell in a room that did not have one, new cracking in the plaster near a wall junction.
Autumn is a good time to spot these because the ceiling has had a dry summer to recover. Anything showing now has been getting wet recently.
If you find something, now is the cheap time
There is a real difference between booking a repair in October and calling someone out in January. In October we can pick a dry day, work at a sensible pace and do the job properly. In January we are working around weather, often making something safe temporarily and coming back later, and you have had water getting into the structure for however long it took to notice.
If what you have found looks more like a failing roof than a repair, our guides on repair versus replace and the signs a roof needs replacing will help you work out which conversation you are having.
Not sure what you are looking at?
If you would rather not climb up, or you have found something and cannot tell how serious it is, we will come and look. It is free, and if the roof is fine we will say so. We are not in the business of inventing work in September to fill the diary in November.
Call 07976 730433 or request a visit here.
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