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Home / Can blocked gutters cause roof leaks?
Short answer: Usually not, in Rodney Cheel’s experience. When gutters are hung correctly, a blocked gutter overflows between the back of the gutter and the fascia, outside the house. Leaks into the roof usually come from a blocked roof valley or a roof defect, such as a broken tile, broken ridge caps or a failed seal around a skylight or flue. Blocked gutters still cause overflow and rust, so clear or guard them, but find the leak’s real source first.
Rodney Cheel has worked at All Seasons Gutter Guard since 2009 and now inspects and quotes gutter, gutter guard and roof jobs every week. He explains that the gutters he deals with are hung so that, when a blockage stops water reaching the downpipe, the overflow escapes between the back of the gutter and the fascia. That is the designed overflow path, and it keeps the water outside the house.
Even when overflow reaches the eaves, Rodney says it should not reach the house itself, because eaves typically extend around 450 to 600 mm from the wall.
“So water shouldn’t really get into the house unless the valleys are blocked.”
Rodney Cheel
Overflow arrangements do vary. The Australian Building Codes Board’s guide to gutter and downpipe provisions describes several, including front-face overflow and a controlled gap at the back of the gutter (ABCB guide, pages 4 to 5). If you are unsure how your gutters are set up, ask the person inspecting them.
What a blocked gutter does cause is overflow: the dripping you hear at night when it rains, water running down the fascia onto the ground, and staining at gutter joins.
A valley is the channel where two roof slopes meet at an internal corner. Rodney says leaves wash down the valley and pile up at the bottom, where it meets the gutter. When it rains, the water cannot get into the gutter, so it backs up the valley, generally about a metre up the roof, and floods over the edges into the roof space.
A tiled roof with a valley, a skylight and a flue: three places Rodney checks when tracking a leak.
Gutter guard does not solve this on its own. Rodney has seen homes with guard fitted to every gutter but not the valleys. Debris catches where the mesh meets the valley, builds up and turns to compost, and the valley floods in the same way. Owners then need to cover the valleys as well, or keep them clear.
A roof valley covered with gutter guard mesh, the step Rodney recommends so leaves cannot pile up at the bottom of the valley.
“Generally, when a roof is in sound condition, it shouldn’t leak.”
Rodney Cheel
When Rodney is called to a leak, the causes he finds are usually one of these:
On older tiled roofs, a visible dip in the tiles tells him moisture has been getting in somewhere and the roof needs attention. For the repairs themselves, see roof restoration in Adelaide.
One customer who wanted gutter guard also mentioned a leak. Inside, Rodney saw the ceiling stain sat directly below a valley, with stains and mould showing it had been leaking for a while. On the roof he found a smashed tile, caved in to leave a hole, right next to the valley.
At another home, the owner had mould in the eaves in four places. From the ladder, Rodney could see that roof tiles had been pulled back during earlier gutter work and never put back over the gutter, leaving a gap between the tile ends and the fascia. Every time it rained, water ran straight into the eaves.
The first thing Rodney learned to spot is dirt and staining dribbling from gutter joins, corners, downpipes and the bottom of the fascia, the sign of leaks and overflow over time. Rust marks on the underside of a gutter show it is rusting through from the inside.
If there is a leak inside, he notes where the ceiling stain sits, then checks the roof above it: valleys, tiles, ridge caps and anything that penetrates the roof. He also checks whether the existing gutters are worth protecting. On one recent quote, the gutters and downpipes were already rusting and leaking, so he told the customer gutter guard would be wasted money on those gutters. The customer replaced the gutters and added guard at the same time.
Not if the leak comes from a tile, ridge cap or penetration. What gutter guard does, Rodney says, is keep leaves out of the gutters so you are not up on a ladder cleaning them as often. Before fitting it he checks that the job can be done properly:
Gutter guard carried up the valley as well as along the eaves gutter, so debris cannot build up where the two meet.
Read more about gutter guard and gutter protection in Adelaide.
Before you call anyone, Rodney suggests looking for these without climbing:
Tell the person assessing your roof what you have seen, and whether the water is outside at the gutter or appearing inside the house.
Answers from Rodney Cheel, Gutters and Roofing Expert at All Seasons Gutter Guard, based on his interview on 21 October 2026.
Leaf debris is by far the most common cause Rodney Cheel sees, especially gum leaves in leafy suburbs. Vermin are the next: rats, mice, birds and possums nest in gutters and roof corners. Pigeons roosting under solar panels leave droppings that wash into the gutter and grow weeds. Leaves also pack into downpipes at the first bend, which blocks the whole run.
On a correctly hung gutter, Rodney Cheel says that gap is the designed overflow path, so dripping there usually means the gutter or downpipe is blocked. Clear the gutter and check the downpipe at its first bend. If the gutters are rusting through, replacement makes more sense than cleaning. Gutter guard then reduces how often the blockage comes back.
In the cases Rodney Cheel describes, mould came from roof leaks rather than gutter overflow: a smashed tile beside a valley left stains and mould on a ceiling, and roof tiles left pulled back after earlier gutter work let rain run into the eaves. Overflow from a correctly hung gutter should stay outside, so mould inside points to a valley or roof defect.
It depends on the trees. Rodney Cheel says homes in leafy areas such as Belair fill with gum leaves constantly, and some owners need their gutters cleared monthly or even weekly. In his experience, paying someone to clean them typically costs around $300 to $400 a visit, an expensive exercise when it is needed that often.
Yes, but far less often. Rodney Cheel says gutter guard means you are not up on ladders cleaning gutters as regularly, which cuts the risk of a fall and a tedious job. It still needs maintenance, especially on shaded roofs under heavy leaf fall, where moss can grow, and around valleys, where debris can collect if the valley is not covered.
Rodney Cheel looks for mesh that is secured firmly and finished neatly. One detail he checks is the spacing of the fixings along the gutter: in his experience they should be around 250 mm apart. When they are more than 500 mm apart, anything that lands on the mesh can push it down into the gutter.
Yes, but Rodney Cheel says it is less common than on tiled roofs. Leaks on metal roofs usually come from penetrations such as skylights, whirlybirds and flue or chimney flashings, or from a perished rubber seal on a roofing screw. A failed screw seal usually causes a slow leak that runs down the sheet to the gutter rather than dripping inside.
If you have overflowing gutters, a leak or both, mention everything when you book. Contact All Seasons Gutter Guard or request a free quote, and Rodney will assess what needs fixing before anything is installed. You can also browse the gutter guard FAQs or see completed jobs in the gallery.
Rodney Cheel, Gutters and Roofing Expert, All Seasons Gutter GuardRodney Cheel is the gutters and roofing expert at All Seasons Gutter Guard, where he has worked since 2009 as Operations Manager. He visits homeowners across Adelaide and the Adelaide Hills to inspect, measure and quote gutter guard, gutters and roof restorations, orders the stock, prepares every job for the installers and serves trade and DIY customers.
He started with some installation work and learned the trade on the job, after 19 years in manufacturing. Today he works alongside the company’s gutter guard installers, gutter crews and roof restoration teams.
This guide is general information based on Rodney Cheel’s experience as at October 2026. It cannot diagnose a leak at a particular property. Have your roof and gutters inspected before deciding on repairs.
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