The homeowner's complaint: during heavy rain, water leaked through the drainage system. The crew found leaf guards already on the gutters, and traced the leak to one T-shaped downspout joint, fed from a flat roof with no guards at all.
A leaking downspout in Toronto, with leaf guards already on the house
Quick answer: In September 2026 a Toronto homeowner called DT Cleaning because water leaked through the drainage system during heavy rain. Leaf guards were already installed on the gutters. Gutter cleaning on the house was $250. The crew also looked for why a system with guards still leaked; the downspout work that followed is not part of the $250.
With good guards on the gutters, the crew was surprised that water overflowed from the downspouts at all.
How the crew found which downspout was leaking
Quick answer: The crew checked all the downspouts on the house while water was overflowing. That showed 1 of them was blocked, and blocked well. The blockage sat at a T-shaped joint where one downspout meets another, at the back of the seam.
The blocked downspout, the one leaking at its joint, was the one to take down. The crew also photographed staining on the brick below the T-joint.
Why T-shaped downspout joints clog and leak at the seam
Quick answer: On this Toronto house 2 downspouts meet in a T. One downspout goes inside the other and sits quite tight against the other wall, which our crew says is how these joints are usually installed incorrectly. Debris carried down the first pipe runs into the other downspout and stops at the seam.
Fitted this way, debris coming down one pipe runs into the other and clogs at the back of the seam, and the downspout starts leaking there.
"The problem with this downspout is that T-shaped downspouts like this are usually installed incorrectly. By incorrectly I mean that one downspout goes inside the other one and sits quite tight against the other wall. ... The downspout starts leaking, staining the wall, doing damage that clients, of course, don't see until the damage is already quite serious."
DT Cleaning crew, Toronto, September 2026 (translated from the crew's voice note)
Can a flat roof downspout clog the downspout below it?
Quick answer: Yes, and that is what happened here. One of the 2 downspouts at the T comes down from a flat roof with no guards, just an open downspout. Debris falls into it, runs down the pipe, hits the other downspout and packs the joint at the back of the seam.
One outlet on this house also had grit and small debris covering its floor before the crew fitted a strainer.
What DT Cleaning did about the leaking downspout joint in Toronto
Quick answer: 3 things: the crew cleaned the blocked downspout, sealed the joint with silicone where it leaked, and fitted a metal strainer in the outlet, meant to keep debris from getting into the downspout. Job photos show the pipe sections down on the lawn for the work.
- Clean the downspout. With a section down on the lawn, the crew ran a rod through it.
- Seal the seam. Silicone went on where the joint was leaking.
- Strain the outlet. A metal strainer in the outlet is there to keep debris from going down into the downspout.
Is silicone a permanent fix for a leaking downspout joint?
Quick answer: No, our crew calls it temporary. Cleaning the downspout, sealing the seam with silicone and fitting the metal strainer are a temporary solution, because the T-joint is still built the same way. For a permanent fix the crew proposed to the homeowner separating the 2 downspouts and adding 1 additional downspout.
Separating the downspouts takes the T out of the system.
What the gutter cleaning cost on this Toronto job
Quick answer: Gutter cleaning alone on this Toronto house was $250 in September 2026. The downspout work, cleaning the blocked downspout, sealing the seam and fitting the strainer, is not part of that figure and is not priced in this article. The permanent fix was proposed to the homeowner.
| Work | What it included | Price |
|---|---|---|
| Gutter cleaning | Gutter cleaning only | $250 |
| Downspout joint repair | Blocked downspout cleaned, seam sealed with silicone, metal strainer fitted in the outlet | Not included in the $250; not priced in this article |
| Permanent fix | Separate the 2 downspouts and add 1 downspout | Proposed to the homeowner |
Our general eavestrough cleaning price ranges by house type are on the eavestrough cleaning cost page for Toronto.
Do gutter guards stop a leaking downspout?
Quick answer: Not on their own. This Toronto house had leaf guards on its gutters and still leaked in heavy rain, because the clog came from a flat roof with no guard. Debris ran down that 1 open downspout and settled at the back of the seam in the T-joint below, where the 2 downspouts meet.
What Toronto homeowners can take from this leak
Quick answer: Watch where water leaves the system in heavy rain, look at the wall under downspout joints, know which parts of the roof have no guards, and treat sealant on a badly fitted joint as a patch. On this house the leak was traced to 1 T-joint fed by 1 unguarded flat roof downspout.
On this house the homeowner's complaint was water leaking through the drainage system during heavy rain. The Government of Canada advises checking eavestroughs and downspouts at least twice per year, in fall and spring, to remove debris such as leaves and sticks.
Gutter cleaning and downspout repair across Toronto and the GTA
Quick answer: DT Cleaning cleans gutters and handles eavestrough and downspout repair across Toronto and the GTA. The company has 500+ five-star Google reviews, $2M CGL insurance and WSIB, and is Working at Heights certified. Gutter cleaning alone on this Toronto job was $250 in September 2026.
If water leaks from your drainage in heavy rain, see our gutter cleaning in Toronto page and our downspout repair case study from Toronto, where a badly installed downspout was taken down and reinstalled. We work in these areas:
Our crews are Working at Heights certified. Ontario's working at heights training page explains that the training is mandatory for workers on construction projects who use fall protection devices, and CCOHS publishes safety information on portable ladders. Where the water ends up matters too: the City of Toronto's mandatory downspout disconnection page notes that during heavy rain the sewers can become overloaded, which can increase the risk of basement flooding, and that water should flow away from a building's foundation.
Leaking downspout: questions Toronto homeowners ask us
Why does my downspout leak in heavy rain when I already have gutter guards?
Because the clog may not be in a guarded gutter. On this Toronto house the blockage sat in a T-shaped downspout joint fed by a flat roof with no guard, and in heavy rain water leaked out through the seam.
How do you find which downspout is leaking?
On this house, the crew checked all the downspouts while water was overflowing, and that showed 1 of them was blocked, quite heavily, at a T-shaped joint.
Why do T-shaped downspout joints clog?
Our crew says they are usually installed incorrectly, with one downspout pushed inside the other and tight against its wall. Debris coming down the first pipe can stop at the back of the seam and build a plug.
Can debris from a flat roof block the downspout below it?
Yes. On this job one downspout came down from a flat roof with no guards, just an open downspout. Debris fell in, ran down the pipe and packed the T-joint where it met the other downspout.
Why does a clogged downspout leak at the seam?
On this house the plug formed at the back of the joint's seam, and the downspout started leaking there, at seam level, staining the wall.
Why didn't I notice the damage from a leaking downspout?
Our crew's experience is that a leaking downspout stains the wall and does damage homeowners do not see until it is already serious. After a heavy storm, look at the wall under each downspout joint.
What should I do if water is coming out of my downspout joint?
Get the downspout cleaned, then deal with why it clogged. On this Toronto house the crew cleaned the downspout, sealed the seam, fitted a metal strainer and proposed a separate downspout.
Is silicone a permanent fix for a leaking downspout joint?
No. Our crew sealed this joint with silicone and fitted a strainer, and calls both a temporary solution. The joint is still built the same way.
What does a metal downspout strainer do?
It sits in the outlet and is meant to keep debris from getting into the downspout. The crew fitted one on this house as part of the temporary fix.
What is the permanent fix for a clogged T-joint?
On this job the crew's proposed permanent fix was to take the T out: separate the 2 downspouts and add 1 additional downspout.
Do gutter guards stop downspout clogs?
Not on their own. This house had leaf guards and still clogged, because the debris came down a flat roof downspout with no guard and settled in a joint below.
How much does gutter cleaning cost in Toronto?
On this Toronto house, gutter cleaning alone was $250 in September 2026. The downspout cleaning and joint repair are not part of that figure. Our general price ranges by house type are on our eavestrough cleaning cost page for Toronto.
Related downspout case studies from our crews
Leaf guards on, and water still leaking in the rain?
On this Toronto job our crew cleaned the gutters, checked every downspout while water was overflowing and found the joint that was leaking. Call to have your gutters cleaned and your downspouts looked at.
