Roof Leak Diagnosis in Toronto & the GTA
A roof leak diagnosis is a detailed inspection designed to identify the likely source of water entering your home or building before a roof repair is recommended. Roofer On Demand physically accesses the roof to inspect the roofing system, flashing, penetrations, skylights, vents, pipe stacks, chimneys, and other vulnerable areas that may be contributing to the leak.
Roof leak diagnosis starts at $79 + HST for homes up to two storeys, $299 + HST for three-storey homes, and $149 + HST for commercial roofs.
Roof Leak Diagnosis Pricing
The cost of a roof leak diagnosis depends primarily on the type and height of the property because roof access, safety requirements, and the complexity of the roofing system can vary.
| Property Type | Roof Leak Diagnosis Fee |
|---|---|
| Homes Up to Two Storeys | $79 + HST |
| Three-Storey Homes | $299 + HST |
| Commercial Roofs | $149 + HST |
These fees apply to roof leak diagnosis under standard access conditions. Properties with unusual access requirements, exceptionally steep or complex roofing systems, or other special conditions may require additional assessment.
What Is a Roof Leak Diagnosis?
A roof leak diagnosis is more than looking at the area where water appears inside the building. Water can enter the roofing system at one location and travel along roof decking, framing, insulation, pipes, or other building components before becoming visible somewhere else.
This means that a ceiling stain directly below a particular section of roof does not necessarily identify the actual point of water entry.
Our objective is to investigate the surrounding roofing system and identify the most likely source of the leak before recommending the appropriate repair.
What Do We Inspect During a Roof Leak Diagnosis?
Every roof is different, so the inspection is based on the roofing system, the location of the reported leak, the roof configuration, and the conditions observed during the assessment.
We inspect the roofing surface as well as roof penetrations and transition points that may allow water to enter.
Roofing Materials and General Roof Condition
The technician evaluates the condition of the roofing materials in and around the suspected leak area. On an asphalt shingle roof, this may include checking for missing, cracked, lifted, deteriorated, improperly installed, or damaged shingles.
We also look for visible deterioration, previous repairs, exposed fasteners, damaged roofing components, and other conditions that may compromise the roof’s ability to shed water.
Roof Vents
Roof vents create penetrations through the roofing system and must be properly installed and flashed. During a roof leak assessment, we inspect accessible roof vents and the roofing immediately surrounding them for visible damage, deterioration, installation problems, or potential water-entry points.
Plumbing Pipe Stacks
Plumbing vent pipes typically pass directly through the roof. The pipe boot or flashing surrounding the penetration can deteriorate, crack, separate, or become damaged over time.
Because a failed pipe-stack flashing can allow water directly into the roofing assembly, these penetrations are an important part of a thorough roof leak diagnosis.
Chimney Flashing
Chimneys create one of the larger and more complex penetrations through a sloped roof. The flashing where the chimney meets the roofing system must manage water from several directions.
We inspect accessible chimney flashing and the surrounding roofing for visible deficiencies that could contribute to water infiltration.
Chimney Brick and Chimney Cap
Not every leak near a chimney originates from the roof covering or flashing. Deteriorated brick, mortar joints, masonry, or conditions at the top of the chimney can also allow moisture into the structure.
When a chimney is present and relevant to the reported leak, we visually assess accessible portions of the chimney brickwork, mortar, flashing, and top of the chimney for conditions that may require further attention.
Skylights and Skylight Flashing
If a skylight is located near the affected area, it becomes an important part of the investigation. A leak around a skylight does not automatically mean the skylight itself has failed.
Water may originate from the skylight flashing, waterproofing, surrounding shingles, seals, roofing above the skylight, or another nearby component.
We assess the visible condition of the skylight, its flashing system, surrounding roofing, and relevant waterproofing details where they can be evaluated.
Roof Valleys and Transitions
Roof valleys carry a significant amount of rainwater and melting snow. Intersections between roof sections, additions, dormers, walls, and changes in roof slope can also create areas where proper flashing and waterproofing are especially important.
When these areas are located near the suspected leak, they are included in the investigation.
We Physically Access the Roof — We Don’t Rely on Drones
Roofer On Demand performs roof leak diagnosis by physically accessing the roof when conditions allow safe access. We do not substitute a drone flyover for a hands-on roof inspection.
Drone images can provide an overview of a roof, but diagnosing a leak often requires a closer assessment of flashing, shingles, penetrations, sealants, previous repairs, transitions, and other details that may not be adequately evaluated from an aerial image.
By climbing onto the roof, our technician can examine the relevant roofing components at close range and better understand how the different parts of the roof are interacting.
Roof access is always subject to weather, roof condition, pitch, ice, snow, and other safety considerations.
Attic Inspection Can Help Trace a Roof Leak
Whenever practical and when safe attic access is available, we prefer to investigate the reported leak from inside the attic as part of the diagnostic process.
The attic can provide information that is not visible from the exterior roof surface. Depending on the conditions, we may be able to observe water staining, moisture patterns, deteriorated roof decking, staining around penetrations, or other evidence that helps narrow down the path of water infiltration.
Comparing what is visible inside the attic with what is observed on the exterior roof can provide a more complete understanding of the problem.
Not every property has accessible attic space, and some finished or low-clearance areas cannot be safely inspected. When suitable access is available, however, attic investigation can be a valuable part of the roof leak diagnosis.
Why the Location of a Ceiling Stain Can Be Misleading
One of the challenges of diagnosing roof leaks is that water does not always travel straight down from the point where it enters.
Water can follow roof decking, rafters, trusses, pipes, insulation, or other surfaces before finally reaching the ceiling. As a result, the visible stain inside the home may be several feet away from the exterior roofing defect.
This is why simply repairing the roof directly above an interior stain can sometimes fail to solve the problem.
A proper diagnosis considers both the interior evidence and the roofing system above and around the affected area.
Common Sources of Roof Leaks
Roof leaks can originate from many different components of the roofing system. Some are caused by storm damage or aging materials, while others result from flashing deficiencies, previous repairs, or installation problems.
Common areas investigated during a roof leak diagnosis include:
- Missing, damaged, lifted, or deteriorated shingles
- Roof vent flashing
- Plumbing pipe-stack flashing and boots
- Chimney flashing
- Chimney masonry and mortar deterioration
- Conditions at the top of the chimney
- Skylights and skylight flashing
- Roof valleys
- Wall-to-roof transitions
- Dormers and roof intersections
- Exposed or improperly sealed fasteners
- Previous roof repairs
- Flat roof membrane details
- Roof penetrations and transitions
Residential Roof Leak Diagnosis
For residential properties up to two storeys, our roof leak diagnosis fee starts at $79 + HST.
The assessment focuses on identifying the likely source of the reported leak by examining the affected area, physically inspecting the roof where safely accessible, and evaluating relevant roofing components and penetrations.
For three-storey homes, the roof leak diagnosis fee starts at $299 + HST because accessing these roofs generally requires additional setup, equipment, and safety considerations.
Commercial Roof Leak Diagnosis
Commercial roof leak diagnosis starts at $149 + HST.
Commercial and flat roofing systems can present different leak patterns than sloped residential roofs. Water may travel beneath roofing membranes or insulation before becoming visible inside the building, making the location of an interior leak an unreliable indicator of the exterior defect.
Depending on the roofing system and accessible areas, our assessment may include the membrane, seams, penetrations, drains, curbs, flashings, rooftop equipment transitions, previous repairs, and other areas relevant to the reported water infiltration.
What Happens After We Identify the Likely Source?
Once the assessment is completed, we explain the conditions observed and the likely source or sources contributing to the leak.
If the problem is repairable, we can recommend an appropriate roof repair based on the condition of the existing roofing system. Depending on the findings, this may involve shingles, flashing, a roof penetration, chimney-related roofing details, skylight flashing, a localized section of roofing, or another affected component.
The objective is not simply to cover the visible area with sealant. The repair recommendation should address the roofing condition that is allowing water to enter whenever that source can be reasonably identified.
When Should You Schedule a Roof Leak Diagnosis?
A roof leak should be investigated as soon as practical after signs of water infiltration appear. Early warning signs can include ceiling stains, dripping water, damp drywall, moisture around a skylight or chimney, staining in the attic, or leaks that appear only during heavy rain or snowmelt.
Delaying an investigation can allow repeated water entry to affect insulation, roof decking, framing, drywall, and interior finishes.
Even intermittent leaks should be investigated. A roof that leaks only during wind-driven rain, prolonged storms, or melting snow may still have a roofing or flashing deficiency that becomes active only under specific weather conditions.
Book a Roof Leak Diagnosis
If you are seeing water stains, active dripping, attic moisture, or other signs of a possible roof leak, Roofer On Demand can assess the roofing system and investigate the likely source of water entry.
Our approach combines a physical roof inspection with an assessment of relevant roof penetrations, flashing, roofing materials, and, where accessible, the attic to provide a more complete understanding of the leak.
Roof leak diagnosis starts at $79 + HST for homes up to two storeys, $299 + HST for three-storey homes, and $149 + HST for commercial roofs.
Schedule your roof leak diagnosis with Roofer On Demand.