YS Roofing handles full roof replacements for residential and commercial properties across Markham and York Region. We assess, recommend, and install, with honest advice on whether you actually need a replacement or whether a targeted repair will do.
Most Markham homeowners do not think about their roof until something goes wrong. Water on the ceiling, a missing shingle spotted from the driveway, or a home inspector flagging issues during a sale. By the time any of those things happen, the roof has usually been failing quietly for one or two seasons. The question is never just “is my roof bad?” It is “how bad, and what do I do about it?”
Ontario’s climate makes that question harder than it looks. Markham roofs face freeze-thaw cycling every winter, ice dams that form along soffits and eavestroughs, UV exposure in summer that breaks down asphalt binder, and wind events that lift poorly seated shingles. A roof that would last 25 years in a mild climate may be showing serious wear at 17 or 18 years here in York Region. The lifespan numbers you read on shingle packaging assume ideal conditions. They do not account for a Canadian winter.
This guide covers how to decide between repair and replacement, what drives cost in Markham specifically, and what the replacement process looks like from first call to final walkthrough.
Act on This Immediately
Call us before reading further if any of the following apply:
- Water is actively entering the home through the roof deck
- Your ceiling or attic insulation shows signs of moisture staining or mould growth
- You can see daylight through the attic from inside the home
- Shingles are lifting or missing across multiple sections after a storm
- Your roof has already been repaired twice in the same area and the problem has returned
- You are preparing to list your home and a pre-sale inspection flagged the roof
Any of these warrants a prompt call. Delaying on an active water intrusion issue adds interior damage costs that a replacement alone will not fix. Reach us at 647-667-1367.
What Most People Get Wrong
They treat age as the only indicator. A 20-year-old roof on a south-facing slope with minimal attic ventilation may need replacing today. A 20-year-old roof on a shaded north-facing property with proper ventilation may have several years left. Age matters, but it is not the whole picture. Ventilation, slope, material grade, and installation quality all affect how fast a roof actually ages.
They repair when replacement is the better financial call. If a roof is 17 years old and needs a $1,800 repair, that repair might buy 18 months before the next problem appears. A full replacement at that point spreads the cost over 20-plus years. We see this pattern regularly in the older neighbourhoods around Unionville, where homes built in the 1990s and early 2000s have had multiple rounds of patching that added up to more than a replacement would have cost.
They assume a new layer of shingles over old ones is fine. Ontario’s building codes permit a second layer in some cases, but adding shingles over a failing base does not fix the underlying problem. It adds weight, traps heat, reduces the lifespan of the new shingles, and masks deck damage that should be addressed.
Overlay vs. tear-off: the honest comparison
Factor | Overlay (shingles over shingles) | Full tear-off |
Upfront cost | Lower | Higher |
Deck inspection | Not possible | Full inspection included |
Lifespan of new shingles | Shortened by trapped heat | Full manufacturer lifespan |
Ontario Building Code | Permitted in limited cases | Always compliant |
Warranty eligibility | Often voided or restricted | Full GAF warranty available |
Our recommendation | Rarely appropriate | Standard for most Markham homes |
They wait until the end of the season. A roof showing active granule loss or multiple soft spots going into November is a problem. York Region winters are not kind to a compromised roof deck. Ice dams form along the eaves when heat escapes through a poorly insulated or poorly ventilated roof, and water pooling behind those dams finds any gap in the shingle roofing system.
When Is the Best Time to Replace a Roof in Ontario?
Late spring through early fall is the optimal window for roof replacement in Ontario. Temperatures between 10°C and 25°C allow asphalt shingles to seat and seal properly. Cold-weather installations are possible, but adhesive strips on shingles require hand-sealing below 5°C, which adds labour time.
The worst time to discover you need a replacement is November. Material lead times, contractor scheduling, and short daylight hours all tighten. If your roof is showing failure signs in the fall, address it before winter, not after.
We complete replacements year-round across Markham. Cold-weather jobs are done correctly, not rushed. But if you have flexibility, booking in spring or early summer gives you the best conditions and more scheduling options.
How Long Should a Roof Last in Markham's Climate?
Shingle type | Manufacturer rating | Real-world GTA lifespan |
3-tab asphalt | 20–25 years | 15–18 years |
Architectural (laminate) | 30 years | 20–25 years |
Premium impact-resistant | 30–50 years | 25–35 years |
Modified bitumen (flat) | 15–20 years | 12–18 years |
TPO membrane (flat) | 20–30 years | 15–22 years |
Three factors shorten these lifespans faster than anything else in this climate:
Inadequate attic ventilation. When heat builds in an attic, it accelerates shingle degradation from below. Ice dams form when warm air escapes through the roof deck and melts snow at the peak, which refreezes at the cold eaves. Markham homes built before 2000 frequently have insufficient soffit-to-ridge ventilation, and we see the damage this causes consistently across the older subdivisions.
Ice and freeze-thaw cycling. Water expands when it freezes. Any water that works its way under a shingle or into a small crack in flashing will expand and force that gap wider every freeze cycle. After four or five Ontario winters, small problems become structural ones.
UV exposure on south-facing slopes. The south face of a Markham roof takes the hardest UV hit, and granule loss accelerates on that side first. If your roof looks worse on one side, that is why, and that side sets the clock on the whole system.
7 Signs Your Markham Home Needs a Roof Replacement
- Granule loss filling the eavestroughs. Finding significant granule accumulation in your gutters means the shingle surface is breaking down. Granules protect the asphalt layer from UV. Once they go, the shingle degrades quickly.
- Curling or cupping shingles. Shingles curl upward at the edges (cupping) or downward at the center (clawing) when they are drying out and losing flexibility. Both indicate the material is past its serviceable life.
- Bald patches or exposed asphalt. Sections with no granule coverage are no longer providing weather protection. One or two bald patches can sometimes be replaced; widespread bald areas signal system-wide failure.
- Sagging sections of the roof deck. Any visible dip or soft spot when you walk the roof (or view it from the ground) points to deck damage below the shingle layer, typically from moisture intrusion over time. This requires more than new shingles.
- Flashing failures around chimneys, skylights, or vents. Flashing is the metal sealing around penetrations. When it cracks, lifts, or pulls away, water enters. If this is happening on a roof already 15-plus years old, the shingles around those areas are typically in similar condition.
- Multiple areas of repair history. A roof patched in three or four locations over the past five years is telling you something. Each repair site is a symptom of a system failing across the board.
- Interior signs: staining, mould, or light in the attic. Water stains on attic insulation or ceiling drywall, or visible daylight through the roof deck, indicate the system has already been breached.
Roof Repair vs. Roof Replacement: How to Decide
The repair-vs.-replace decision comes down to three factors: the age of the roof, the scope of the damage, and the cost comparison over time.
Situation | Recommended action |
Roof is under 10 years old, isolated damage | Targeted repair |
Roof is 10–15 years old, damage in one section | Repair, monitor annually |
Roof is 15-plus years old, damage in multiple areas | Replace |
Roof is 15-plus years old, single failure but widespread granule loss | Replace |
Active water intrusion reaching living space | Assess immediately, likely replace |
Repeated repairs to same area within 3 years | Replace |
Pre-sale inspection flagging the roof | Replace for maximum value outcome |
If your roof is under 12 years old and the damage is localized to one section or one penetration point, roof repair is almost always the right move. We will tell you that directly. We are not interested in selling a replacement to a homeowner who does not need one.
Markham Homes: What We See on the Roof
Markham’s housing stock is heavily concentrated in two build eras, and the roofing problems we encounter track closely with those periods.
1985–2000 builds (Unionville, Milliken Mills, Wismer Commons area). These homes are now 25 to 40 years old. Most have had at least one shingle replacement already, sometimes an overlay rather than a full tear-off. The original ventilation systems in many of these homes are undersized by current standards. We regularly find damaged decking, compressed attic insulation, and inadequate soffit-to-ridge airflow. If your home was built in this period and you have not replaced your roof in 20-plus years, an assessment is overdue.
2000–2015 builds (Angus Glen, Box Grove, Wismer). Builder-grade three-tab shingles were standard on a significant portion of GTA subdivision homes completed in this period. Three-tab material rated at 20–25 years by the manufacturer typically performs closer to 15–18 years in Ontario’s climate. These roofs are now entering or approaching their failure window. Granule loss, cracking along the tab cutouts, and lifting in wind events are the most common presentations we see on this housing stock.
Flat roofs on Markham townhomes. Many Markham townhome builds from the 2000s onward include a partial or full flat roof section, typically covered in modified bitumen. These systems have a shorter service life than pitched shingle roofs and fail differently. Ponding water, membrane cracking at seams, and drain blockages are the primary failure modes. See our flat roof replacement page for the specifics.
What causes ice dams in Markham homes? Ice dams form when heat escapes through the roof deck, melts snow at the upper slope, and that meltwater refreezes at the cold eaves and soffit line. The underlying cause is almost always inadequate attic insulation, insufficient ventilation, or both. The ice dam is a symptom. The ventilation deficit is the problem. A replacement done without addressing ventilation will face the same ice dam risk within a few winters.
3-Tab vs. Architectural Shingles: Which Is Right for Your Markham Home?
Factor | 3-Tab | Architectural (laminate) |
Thickness | Single layer | Double-layer laminated |
GTA lifespan | 15–18 years | 20–25 years |
Wind resistance | 60–90 mph typical | 110–130 mph typical |
Appearance | Flat, uniform | Dimensional, textured |
Cost | Lower upfront | 10–15% more, longer return |
GAF warranty eligibility | Basic | Enhanced coverage available |
Our recommendation | Not for new installs | Standard for all YS Roofing replacements |
We do not install 3-tab shingles on replacement jobs. The cost difference over a 20-year period does not justify the reduced lifespan and lower wind resistance, particularly given Markham’s storm exposure. Architectural shingles are the baseline on every replacement we do.
What Does a Full Roof Replacement Include?
Tear-off and disposal. We remove the existing shingle layer (and any underlayment) down to the roof deck. This is the only way to assess deck condition and address any damage before new material goes on.
Deck inspection and repair. Once the deck is exposed, we check every section for soft spots, rot, or moisture damage. We replace damaged deck boards before anything else happens. You approve any additional scope before we proceed.
Ice and water shield. In Ontario, proper installation requires ice and water shield membrane along the eaves and in valleys, the areas most vulnerable to ice dam backup. This is required under Ontario Building Code and non-negotiable in Markham’s climate.
Synthetic underlayment. Laid across the full deck, this provides a secondary moisture barrier beneath the shingles.
New shingles. We install architectural (laminate) asphalt shingles as the standard for residential replacements. As a GAF Certified contractor, we install GAF shingle systems that qualify for enhanced warranty coverage. We review the specific product with you before the job starts.
Flashing replacement. We replace or reseal all flashing around chimneys, vents, skylights, and valleys. Reusing old flashing on a new roof is a mistake we do not make.
Ridge vent installation or assessment. Proper ventilation is part of the job. If existing ridge or soffit ventilation is inadequate, we address it during the replacement.
Site cleanup. We remove all debris. The job is done when the site looks the way it did before we arrived, minus the old roof.
What Does a Roof Replacement Cost in Markham?
Every roof is different. Replacement costs depend on what is found during inspection, roof pitch, complexity, deck condition, and material requirements. The only accurate number comes from an on-site assessment. YS Roofing provides free estimates with no obligation. Financing is available through Financeit for homeowners who prefer to manage the cost over time.
What to Expect When You Hire YS Roofing
Assessment (free). We come out to your Markham property, inspect the roof, and give you an honest recommendation. The assessment typically takes 30 to 45 minutes. Before we leave, you will know whether the right call is repair, replacement, or monitoring. Photos of findings are included.
Proposal (within a few days). You receive a clear, itemized written quote. No vague line items. You know exactly what is included, what materials are used, and what the timeline looks like.
Scheduling. Most residential replacements in Markham are scheduled within one to three weeks of contract signing, depending on season.
Installation day. A standard residential replacement on a typical Markham detached home takes one to two days. Larger or more complex roofs may take longer. The crew arrives early and works through until completion. The site stays clean throughout.
Final walkthrough. Before we leave, we walk the job with you. You see the completed work, we confirm cleanup is done, and we answer any questions about your warranty and maintenance.
Documentation. You receive copies of the GAF warranty registration and our workmanship guarantee. Both transfer to a new buyer if you sell.
When to Replace a Roof in Ontario: The Short Answer
A roof in Markham typically needs replacement when it is 17 to 22 years old and showing multiple failure signs including granule loss, curling shingles, deck damage, or repeated repair failures. Ontario’s freeze-thaw cycles, ice dams, and UV exposure accelerate shingle wear compared to milder climates, making age alone an unreliable guide.
Replacement is the better financial choice over continued repair when the roof is past the 15-year mark and damage appears in more than one area. Ontario Building Code requires ice and water shield installation at eaves and valleys, a standard included in every YS Roofing replacement job.
Frequently Asked Questions
How long does a roof replacement take in Markham?
Most standard residential replacements take one to two days. A typical Markham detached home with a straightforward hip or gable roof is usually completed in a single day with a full crew. Complexity, including multiple dormers, steep pitch, or extensive deck repairs, can add time. We give you a realistic timeline in the proposal before any work begins.
Can I stay in my home during a roof replacement?
Yes. Roof replacement creates noise and some vibration, but there is no reason to vacate. Most of our Markham clients are home during the job. We secure tarps and manage debris throughout the day.
Does a new roof add value to a home in Markham?
It does. A new roof removes a major negotiating variable for buyers in the York Region market, where home inspectors flag aging roofs consistently. GAF warranty coverage transfers to a new owner and is a documented asset during a sale.
What is an ice and water shield, and do I need it?
Ice and water shield is a self-adhering membrane applied to the roof deck at eaves, valleys, and around penetrations before shingles go on. It creates a secondary barrier against water that backs up behind ice dams. It is required by Ontario Building Code on new installations.
Should I repair or replace my roof before selling my home?
If the roof is more than 15 years old or has any flagged issues, replace it before listing. A roof flagged in an inspection report affects your negotiated price, usually by more than the replacement would have cost. For roofs under 10 years old with no flagged issues, repair only what is needed.
What warranty comes with a YS Roofing replacement?
As a GAF Certified Residential Roofing Contractor, we install GAF shingle systems that qualify for manufacturer warranty coverage on materials. Workmanship is separately guaranteed. We document and register both warranties. Coverage specifics depend on the product selected, which we review with you before the job starts.
How do I know if my roof deck needs to be replaced?
Deck issues are usually identified once the old shingles are removed. Signs before tear-off include visible sagging, soft spots underfoot when walking the roof, and significant interior moisture staining in the attic. We inspect the full deck during every replacement and flag any areas requiring board replacement. You approve any additional scope before we proceed.
Can roof repairs void the manufacturer warranty?
Yes, in some cases. If repairs are made by a non-certified contractor using non-GAF materials on a GAF warranted roof, the manufacturer warranty can be voided or restricted. This is one practical reason to use a GAF Certified contractor for any work on a GAF system, not only the original installation.
What is the best time of year to replace a roof in Ontario?
Late spring through early fall gives the best conditions. Asphalt shingles seat and seal most reliably between 10°C and 25°C. Cold-weather installations are done correctly but require hand-sealing of adhesive strips below 5°C. If your roof is failing now, do not wait for spring. Delaying through an Ontario winter on a compromised roof adds interior damage risk.
Book Your Free Roof Assessment
A roof leaking in one spot rarely stays contained. Water finds the path of least resistance, and in Ontario winters, that path expands with every freeze cycle. A free assessment from YS Roofing identifies exactly what is failing and what can be repaired versus what needs replacing.
GAF Certified contractors carry requirements that standard roofers do not. Licensing and insurance are mandatory, not optional. Fifteen years of working across Markham and York Region means we have seen this climate do its worst to every roof type and housing era.
Here is what the assessment looks like:
- Arrives within a few business days of your call
- Takes 30 to 45 minutes on-site
- Includes photos of any findings
- Gives you a clear repair vs. replace recommendation before we leave
- Comes with a written quote if replacement is needed
- Carries no obligation to proceed
Step 1. Call 647-667-1367 or submit a request through our contact page.
Step 2. We schedule a time that works for you.
Step 3. We inspect, give you a straight answer, and hand you the findings in writing.
Book Your Free Assessment | Call 647-667-1367
YS Roofing
Trusted roofing services provider
YS Roofing is a trusted, GAF Certified™ Residential Roofing Contractor with over 15 years of industry experience serving the Greater Toronto Area. Specializing in comprehensive roof replacements, expert repairs, and structural protection, the company is built on a foundation of premium craftsmanship, high-quality materials, and exceptional customer service.