5 Roof Red Flags Every Sarnia Homebuyer Should Watch For | Cheshire Roofing Shares
- Cheshire Roofing Sarnia
- 3 days ago
- 6 min read
When buying a home in Sarnia, the roof is one of the most overlooked yet most expensive parts of the property to repair or replace. It protects everything beneath it, and if it fails, you could face structural damage, insulation problems, and long term water issues.
To help buyers make smarter decisions, Steven Cheshire, owner of Cheshire Roofing, shares the five most common red flags he spots during roof inspections and what they mean for homebuyers.
1. Failed Sealing Strips, Cracked, or Missing Shingles
Why it is a red flag:
Unlike the typical 3-Tab shingle of 20 years ago, architectural shingles of today DO NOT curl. This often leaves a false impression that the shingle is in good condition when in fact it is not.
Cracked and missing shingles are also a sign that th esealing strip has failed and the system has become more susceptible to wind damage. Asphalt shingles typically last between 15 and 25 years, depending on ventilation and weather exposure. In Sarnia’s climate, with freeze and thaw cycles and strong lake effect winds, that lifespan can be shorter.
What to do:
Step back and inspect the roofline from the street. If you notice unevenness, colour variation, or bare patches, the roof may need replacement soon. Ask the seller when the roof was last replaced. If the shingles are more than 15 years old or the repairs look patchy, request a professional inspection before finalising the purchase.
Steven notes, “When shingles start lifting or disappearing, that is not just cosmetic. It is a sign the roof is nearing failure and you will be paying for leak repairs before long.”
2. Stains or Moisture in the Loft
Why it is a red flag:
The loft reveals the true condition of a roof. Brown stains, damp insulation, or a musty odour all point to leaks that may not yet be visible inside the home. Water stains on rafters indicate that moisture has been entering for some time even if the shingles look fine from outside.
In Sarnia’s humid summers and cold winters, attic condensation can also cause mould growth and rot. Poor ventilation traps moisture, which speeds up the deterioration of shingles from below. Most shingle Manufacturers will not warranty a roof without correctly ventilated attic space. A common area of trapped moisture are improperly installed Bathroom Exhausts and Kitchen Range hood Exhausts.
What to do:
Bring a torch to every viewing and inspect the loft if possible. Look for damp or compacted insulation, dark patches on the timber, or rust on nails. These are all early signs of leaks.
If you find evidence of moisture, do not assume it is minor. Have a roofer such as Cheshire Roofing assess the ventilation, soffit openings, and roof vents. Adding a ridge vent can extend roof life, but if water damage has spread, the insulation and sheathing might need replacement.
3. Granules in the Gutters or Downpipes
Why it is a red flag:
Asphalt shingles are coated with small mineral granules that protect against ultraviolet rays and water penetration. Over time, those granules loosen and wash into the gutters. A handful of granules is normal on a new roof, but a consistent build up means the shingles are wearing out.
Once the protective layer is gone, the shingles absorb heat, dry out faster, and crack more easily. It is like the roof losing its sunscreen, and from there, the damage speeds up.
What to do:
During a viewing or inspection, look inside the gutters. If you see a thick layer of black grit, take note. Steven explains, “When we clean out a gutter and find granules piled up, that tells us the shingles are reaching the end of their service life.”
This issue does not always call for immediate replacement, but it is something to consider during negotiations. If the roof is more than 12 years old and losing granules heavily, budget for replacement within five years.
4. Damaged or Loose Flashing Around Chimneys, Skylights, and Vents
Why it is a red flag:
Flashing is the thin metal, often aluminium or galvanised steel, that seals the joints between the roof and vertical structures such as chimneys or skylights. It is one of the most common points of failure because water naturally flows toward these areas.
When flashing is loose, rusted, or badly sealed with caulking, water can seep behind it and rot the decking underneath. Over time, this leads to leaks inside walls or ceilings, often far from where the problem began.
What to do:
Walk around the property and look for exposed metal or lifted edges near chimneys or vent pipes. In the loft, check for discolouration in those same spots.
Steven explains, “Flashing problems are one of the first things we fix on inspection jobs. The good news is that if they are caught early, they are inexpensive to repair. Left alone, they can cause major internal damage.”
If you are serious about buying the property, request a roofing inspection that includes all flashing points. Small resealing jobs might cost a few hundred dollars. Ignored, they can cause thousands in hidden damage.
5. Multiple Layers or Evidence of Patch Repairs
Why it is a red flag:
Some homeowners install new shingles directly over the old ones to save money. While this is allowed under certain conditions, it is not best practice. Layered roofs trap heat, prevent proper fastening, and make it impossible to inspect the decking underneath.
Likewise, visible patches of mismatched shingles often mean leaks were treated reactively rather than properly repaired. Multiple layers or patch jobs can conceal deeper issues such as rot, mould, or poor ventilation.
What to do:
Ask your home inspector to confirm how many layers the roof has. In Ontario, two layers are legal, but if you are buying a house with a double layer, plan for a full tear off next time. Steven says, “You cannot fix a roof properly until you strip it down to the deck. Otherwise, you are just hiding the problem.”
If you notice inconsistent shingle colours or oddly placed vent caps, get a second opinion. It may suggest previous repairs that did not solve the underlying issue.
Final Advice for Homebuyers
A roof that looks fine from the curb may be hiding years of deferred maintenance. The average asphalt shingle replacement in Sarnia costs between $8,000 and $15,000, depending on size and complexity, so it pays to understand what you are buying.
Before closing, hire a qualified roofer to conduct a dedicated roof inspection, not just a general home inspector. Roofing specialists like Cheshire Roofing Sarnia can provide a written condition report, estimate the remaining lifespan, and quote realistic replacement costs.
Steven sums it up: “You do not need to be a roofing expert, but you should know what warning signs look like. If something seems off, it is always cheaper to check before you buy than to fix after you move in.”
Realtor Advice from Carla & Sheri
Buying a home is one of the biggest investments you’ll ever make, and the roof is one of the most important parts to pay attention to. A solid roof not only protects your home — it protects your peace of mind.
As realtors, we always encourage our buyers to look beyond the surface. A beautiful home can lose its appeal quickly if a costly roof replacement is around the corner.
That’s why we recommend:
Ask about the age of the roof early on. If it’s more than 15 years old, plan for a closer inspection.
Include a professional roof inspection as part of your due diligence. Many issues aren’t visible from ground level or in a general home inspection.
Factor potential repairs into your offer strategy. Knowing what you might be facing gives you leverage in negotiations.
Don’t skip insurance questions. Your insurer may ask about the roof’s age and material, and this can affect your premiums or coverage options.
At Living in Lambton Realty Group, we guide you through each step — connecting you with trusted local professionals like Cheshire Roofing, helping you interpret inspection results, and ensuring there are no surprises after closing.
Your home should be a source of comfort, not concern — and with the right advice and support, it will be.
Cheshire Roofing Sarnia
439 Palmerston St S, Unit 2
Sarnia, ON N7T 3P4
519-330-7376
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Carla MacGregor REALTOR®
Initia Real Estate Brokerage
519-464-3230
Sheri Strangway REALTOR®
Initia Real Estate Brokerage
519-331-9048
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