The short answer
Clear gutters at least annually, ideally once the trees are bare in November, and take another look in spring. Houses under trees, with moss on the roof or with flat gutter runs may need a second visit. Overflow in rain, green staining on walls and plants growing in the gutter all say a clear is overdue.
A baseline for most houses
For an ordinary house with a few trees nearby, a single thorough clear each year keeps the gutters running. Late autumn is the best moment, because the worst of the leaf fall is over and the winter rain is still to come. A quick look in spring catches whatever the winter left behind: grit washed off the roof, seeds, and the odd nest.
That is a baseline, not a rule. A gutter carries the water from a whole roof slope through a channel only a few inches wide, so a small amount of debris has a large effect. Two things set how fast it builds up: what sits above the gutter, and how well the gutter drains.
The first is easy to judge from the garden. Overhanging oak, sycamore or birch drop a great deal in autumn, and conifers shed needles through the year. The second is a matter of fall, the slight slope that carries water to the outlet. A shed-gutter maker recommends roughly 1:350, which the eye can barely see from the ground. If a run has sagged or the brackets have slipped, water stands in the low spot and silt settles there, however often you clear it.
When to clear more often
Some roofs and settings call for a second clear in the year, usually in early summer or just after leaf fall in a wet autumn.
- Overhanging trees. Leaves arrive in a short, heavy burst. A clear in November can be filled again by the end of the month if the tree is late to drop.
- Moss on the roof. Moss on tiles or slates loosens and washes down. Roofs that are shaded and damp shed it steadily, and it packs into the gutter as a green sponge.
- Old granular surfaces. Some older tiles and slates shed grit as they weather, and that sediment collects at the low end of the run.
- Low-pitched or shallow-fall runs. Water moves slowly, so debris settles instead of flushing through.
- Terraces with shared gutters. A neighbour's blockage can back water into your length. We cover that arrangement on our page about a shared gutter on a terrace.
If you are not sure, check after the first heavy rain following a clear. A gutter that is already carrying a film of silt is telling you the interval is too long.
Signs that gutters need clearing now
You do not have to climb a ladder to spot trouble. Walk round the house in steady rain and look up.
Water spilling over the front edge in a sheet means the channel is full or the outlet is blocked. A drip from a joint can be a seal failing, but it can equally be water backing up behind a blockage. Dark or green streaks down the wall under the gutter show where overflow has been running for some time. Stonework that stays wet below the eaves, or paint that blisters on a fascia, points the same way.
From the garden, look for tufts of grass or small plants growing along the gutter line. They only root in a layer of compost-like debris that has been there a while. A downpipe that gurgles or runs dry while the gutter is clearly full is blocked at the shoe or in the pipe itself.
Left alone, a standing load of wet debris is heavy. It can pull a bracket loose and tilt the run, and the constant overflow soaks the fascia board behind. We describe what that looks like in our piece on damage from blocked gutters.
What a proper clear involves
A good clear removes the debris, checks the fall, and flushes the outlet. Scooping leaves from the top of the run is the easy part. What matters is what is underneath: the silt packed along the base, the stop-end and the hopper by the downpipe, and the joints.
We work from a ladder with stand-offs or a tower, depending on the height, and bag what we take out rather than dropping it into the garden or onto a lower roof. Once the channel is clear we run water along it. If it pools anywhere, the brackets need adjusting. If a joint weeps, it needs resealing or the seal replacing, which is a separate fix described in our guide to a leaking gutter joint.
Cast iron gutters get a look at the paintwork as well, since a chipped coat lets rust start from the inside. On uPVC, we look for cracked clips and bowed sections that hold water.
Working at height carries a real risk. If your gutters sit above the first floor, over a conservatory, or beside a fragile roof, you want a contractor who brings the right access equipment. What it costs depends on the house and access, and we set that out in how much gutter cleaning costs.
Cutting down the work
Gutter guards, the mesh or brush inserts that sit in the channel, can reduce how much reaches the bottom of the run. They do not remove the need to look. Fine debris and moss still settle on and under the guard, and a guard hides the problem until it overflows.
Cutting back branches that overhang the roof makes a bigger difference than most additions, and so does dealing with moss at source. Where gutters keep overflowing even after a thorough clear, the cause is probably not debris at all. It may be undersizing, a wrong fall or a blocked downpipe, all of which we describe on the page about why gutters overflow.
For a look at the whole roofline, our gutters, soffits and fascias service covers clearing, repair and replacement. The survey is free and includes photographs of your own gutters, and you receive a fixed written price afterwards.
