Replacing a Roof

Replacing a roof means more than putting on new shingles. For homeowners in Markham and across York Region, it usually involves inspecting the roof, tearing off the old materials, repairing any damaged decking, installing underlayment, shingles, flashing, and vents, and finishing with a final inspection so the roof stands up to local freeze-thaw cycles and heavy snow.

We’ve been replacing roofs across Markham for over 30 years. From quick tear-offs on bungalows in Unionville to full replacement jobs on steep multi-level homes in Cathedraltown, we’ve seen it all. This guide is for homeowners in Markham and York Region considering a roof replacement. A roof replacement is one of the biggest investments you can make in your house, and understanding the process helps you make an informed decision about when and how to tackle it.

We’ll walk you through the signs your roof needs replacement, the step-by-step process, material options, cost ranges, timing, repair versus replacement, DIY considerations, and what to expect if you hire Edmunds for the job.

Signs You Need a New Roof

Most asphalt shingles last between 20 and 25 years, but actual roof lifespan in Markham depends on materials, installation quality, and local weather. If yours are getting close to that age, watch for these warning signs:

• Curling edges
• Cracked or missing shingles
• Dark streaks where granules have worn away
• Granules often end up in your eavestroughs, so check there too

Go into your attic space on a sunny day. If you can see daylight through the roof deck, that is a problem. Look for dark stains or wet spots on the underside of the decking; any sign of water damage or mould means the roof is failing. A professional roof inspection catches issues you might miss from the ground. At Edmunds, we inspect the roof surface, attic, flashing, and ventilation before recommending a roof repair or a full roof replacement.

The Roof Replacement Process Step by Step

A roof replacement project is typically divided into several main phases, each with specific tasks and goals. Roof replacement typically involves several main phases, each critical to ensuring a durable and safe result. Here is what to expect when a roofing team arrives at your house for a new roof installation.

Step 1: Roof Inspection and Assessment

Before any roofing materials leave the truck, your roofing contractor should do a thorough inspection covering the shingles, the roof deck, and the attic space below. On older Markham homes from the 1980s and 1990s, we often find ventilation problems that have dried out the decking over time. Catching that early changes the whole roofing project.

Step 2: Choosing Your Roofing Materials

Asphalt shingles are the most popular roofing materials in Markham. They handle our Ontario climate well, come in a range of styles, and are the most cost effective option for most homeowners.

At Edmunds, we install IKO products in three tiers: three-tab shingles, IKO Cambridge architectural shingles, and IKO Dynasty premium shingles. Dynasty provides high wind resistance, which matters during York Region winter storms. We also offer metal roofing and composite shingles for homeowners looking for longer-lasting alternatives. Your roofing contractor can help compare the lifetime value of different materials based on your budget and the local climate.

Step 3: Preparing Your House for Installation Day

Move vehicles off the driveway and clear patio furniture and breakable items from around the house. Falling debris is unavoidable during tear-off, so cover gardens and plants near the foundation with tarps to protect them. Inside, take down wall hangings on the top floor because the vibration from roofing nails can shake things loose. Let your neighbours know the work is coming.

Step 4: Removing the Old Roof

The roofing team strips all existing shingles, old flashing, and other debris down to the bare decking. This is the noisiest part of the job. On some older homes, there may be two or three layers of old shingles stacked up. Removing multiple layers of existing shingles adds about 20% per layer to the cost because of the extra labour and disposal weight.

Step 5: Inspecting and Repairing the Roof Deck

With the old roof stripped away, the crew inspects the decking underneath. Soft, rotted, or delaminated plywood needs to be replaced before new materials go on. Any structural damage at this stage could compromise the entire new roof installation. Plywood repair is common on older Markham homes, often because poor ventilation dried out the deck. At Edmunds, replacement runs about $90 per sheet (4 x 8 feet).

Step 6: Installing New Underlayment and Ice Shield

The Ontario Building Code requires ice and water shield membrane at the eaves and valleys. This waterproof barrier stops ice dam leaks and damage from reaching your house, and ice dams are a real concern in Markham because of our freeze-thaw cycling. At Edmunds, ice and water shield is standard on every new roof installation. Synthetic underlayment covers the remaining decking. Upgrading to full synthetic underlay across the whole roof adds roughly 10%.

Step 7: Installing New Shingles

New shingles go on from the bottom edge up. The roofing team starts with starter shingles along the bottom and sides, then applies the main shingles in staggered rows secured with roofing nails per manufacturer guidelines. The ideal time to install a roof is during mild, dry weather. Shingles are easier to work with and become watertight right away. The sealing strip on heavier laminate shingles gets activated by future hot weather, which in Ontario may not happen until the following summer on a late-season installation.

Proper installation makes a real difference. Cutting corners on nail spacing or alignment leads to problems that void your warranty. Roofing professionals also apply roofing sealant at key transition points to ensure a watertight seal.

Step 8: Install Flashing and Drip Edge

Flashing goes around chimneys, skylights, pipe vents, and anywhere two roof planes meet. Metal drip edge gets installed along the eaves and gable ends to direct water into the eavestroughs. Old flashing is one of the most common leak sources on older roofs. During a roof replacement, all flashing should be replaced with new materials.

Step 9: Replacing Vents

Roof vents are replaced or upgraded during a new roof installation project. Your roofing contractor will assess whether you need ridge vents, soffit vents, or static vents based on the layout of your attic space. Proper ventilation prevents heat and moisture buildup that shortens the life of new shingles. In Ontario, the standard is the 1/300 ratio: one square foot of net free vent area for every 300 square feet of attic.

Step 10: Final Inspection and Cleanup

A good roofing company does a final walkthrough when the job is finished to confirm the installation meets required standards. Check the alignment of the shingles, the flashing, and the overall look of the new roof. The roofing professionals should clean up all debris, old shingles, packaging, and loose nails from your property. Removing debris matters just as much as collecting loose nails and packaging. At Edmunds, we do a magnetic sweep to catch stray nails across the entire yard. Nobody wants a flat tire a week later.

How Much Does It Roughly Cost to Replace a Roof?

Per-Square Pricing

A standard asphalt shingle roof replacement cost in Markham on a typical detached home starts at around $9,000. The range we quote is $5,500 to $18,000, depending on the size of the house, the pitch, and the materials chosen.

Here is what our per-square pricing looks like at Edmunds (one roofing square equals 100 sq ft):

• Three-tab shingles: approximately $350/square
• IKO Cambridge architectural shingles: approximately $360/square
• IKO Dynasty premium shingles: approximately $375/square
• Composite shingles: approximately $750/square
• Metal roofing: approximately $850 to $950/square

These prices reflect Spring 2026 conditions in the Markham area. Costs have risen just over 10% in the past couple of years, driven by rising oil and transportation expenses.

Cost for a 2,000 Sq Ft Roof

For a 2,000 square foot home in Ontario, the roof area is typically larger than the floor area because of overhang and pitch, and replacement cost depends on the roof’s square footage rather than the home’s interior size alone. A home that size usually has between 20 and 25 roofing squares of surface area. At Edmunds, an architectural shingle replacement cost for that range lands between $7,200 and $9,375 before extras. Getting multiple detailed quotes from local roofing contractors is the best way to understand what your specific roof replacement will cost.

Factors That Increase Cost

Several factors can drive the replacement cost up:

• Steep pitch adds 10% to 20% for roofs between 8/12 and 12/12. The roofing team needs safety equipment and extra time.
• Multiple tear-off layers add about 20% per layer.
• Plywood replacement adds $90 per sheet, which is common on Markham homes from the 80s and 90s where attic ventilation was undersized and roof lifespan is shortened in Markham’s climate.
• Complexity from chimneys, skylights, and multiple valleys can add up to 10%.
• Tight access on townhome complexes adds 5% to 10% for extra protection and logistics, and replacing a shared roof on townhomes or semis can involve coordinating scope and timing with your neighbours.

Cheapest Replacement Options

Three-tab asphalt shingles are the least expensive roofing materials for a full replacement, at roughly $350 per square installed. Even among asphalt shingles, three-tab is the budget tier. Keep costs lower by choosing a standard-pitch roof with a single layer to tear off and no structural damage underneath.

Standard re-roofing in Markham does not require a building permit, so there are no permit costs. Permits only apply for structural changes to the roof construction. Compare quotes from more than one roofing contractor, and compare the scope of work and warranty coverage, not just the bottom line.

What Time of Year Is the Cheapest to Replace a Roof?

Late spring through early fall is the best window for roof replacement in the GTA. In Markham, that means May through October when weather conditions are mild and dry.

Off-season jobs can come at a lower price because roofing contractors are less busy. But winter roofing in Ontario is tricky. Cold temperatures make shingles brittle. Snow creates safety risks. And the sealing strip on laminate shingles will not activate until warm weather returns. Weather conditions in Ontario make late spring or early summer the safest bet for most Markham homeowners looking for the best combination of performance and contractor availability.

Should You Repair or Replace Your Roof?

If your roof is 15 years or older, a roof replacement usually makes more financial sense than ongoing roof repair. A practical rule: if the repairs cost more than 25% of a full roof replacement, it is more cost effective to replace the whole thing. Insurance typically does not cover roof replacement caused by normal wear. Sudden damage from events such as fallen trees is handled differently when homeowners make claims.

Typical Roof Repair Costs

Typical roof repair services at Edmunds start at about $300 for materials and labour, but can run into the thousands if there is a bigger underlying issue. We always provide a free quote when the repair would exceed that $300 minimum.

Can You DIY a Roof Replacement?

Hiring a professional roofer for roof installation and replacement is safer and usually the better choice than attempting the work yourself. Roofing is dangerous work even with safety equipment, and proper installation is what makes a roof last. Experienced roofing professionals know how to spot hidden damage and have the training to handle the hazards of replacement safely and correctly, follow manufacturer guidelines, and meet local building codes that keep your warranty valid. There are very few situations where a DIY roof replacement makes sense on a full-sized house.

In Ontario, any roofing contractor working on your house should carry WSIB clearance. That protects you from liability if a worker is injured on your property. Ask to see the certificate before signing a contract.

Ready to Replace Your Roof? Talk to Edmunds

If you are a homeowner in Markham, Unionville, Cornell, Berczy Village, Cathedraltown, or anywhere in York Region, Edmunds Home Improvements is here to help with your roof replacement. We have been guiding homeowners through the roof replacement process for over three decades. We offer free quotes and honest assessments for every roofing project, whether you need a simple repair or a full replacement.

Contact our Edmunds Home Improvements team today to get started.