Roofing options and costs in St. Thomas
St. Thomas, Ontario homeowners are dealing with a roofing market shaped by older housing stock, weather stress, and a fairly tight contractor pool. In a city of 42,840 people, where 67.8% of households own their homes and 57.7% of dwellings were built before 1981, a lot of roofs are reaching the stage where patching stops making financial sense. Older roof assemblies also tend to hide two-layer tear-offs, brittle flashing, and patched decking, which can add time and disposal cost once the crew gets on site. In neighbourhoods with mature homes such as Southwold or around the historic core, we see frequent calls for leak repairs, chimney flashing work, and full replacement quotes after a few storms or a bad winter thaw.
London’s cold, continental climate drives a different pricing pattern than coastal BC or hail-prone Alberta. In St. Thomas, contractors price for snow load, freeze-thaw cycling, and ice-dam control, so robust eave protection, balanced attic ventilation, and proper insulation details are not optional extras if you want the roof to last. Labour availability also matters: shorter practical install seasons in Southwestern Ontario mean crews often book quickly in peak summer, and rates rise when contractors are squeezing work around rain, snow, and cold-weather safety. Material costs have climbed too, especially for asphalt products tied to oil inputs and metal tied to global commodity pricing, so even straightforward jobs can move into the $7,500 – $16,000 range faster than homeowners expect. If you are comparing quotes, the key is to separate basic replacement pricing from upgrades like premium underlayment, thicker shingles, or extra flashing work. The table below gives a realistic starting point for the most common roof systems in St. Thomas.
| Type |
Typical Use |
Lifespan |
Best For |
Price Range |
| Full asphalt shingle replacement (tear-off + new install) |
Most detached homes and bungalow roofs needing full renewal |
18–25 years |
Budget-conscious homeowners wanting a familiar, repairable system |
$7,500 – $16,000 |
| Architectural / laminated shingle (premium asphalt) |
Upgraded sloped roofs where curb appeal and durability matter |
25–35 years |
Owners wanting better wind resistance and a heavier look |
$9,500 – $19,500 |
| Impact-resistant shingle (Class 4 — hail & wind zones) |
Homes exposed to more severe storms or value-driven insurance buyers |
25–40 years |
Extra storm resistance with potential insurance advantages |
$11,000 – $22,000 |
| Metal roofing (steel panels or standing seam) |
Long-life replacement for steep or medium-slope homes |
40–60+ years |
Low-maintenance owners focused on longevity and snow shedding |
$18,000 – $38,000 |
| Flat / low-slope membrane (TPO or EPDM) |
Porches, additions, garages, and low-slope sections |
20–30 years |
Flat roof areas needing watertight seams and dependable drainage |
$12,000 – $30,000 |
| Roof repair + flashing only (no full replacement) |
Localized leaks, chimney repairs, vent or valley flashing issues |
2–10 years depending on condition |
Minor damage where the roof system is still broadly serviceable |
$350 – $3,500 |
Prices are estimates only and vary by project scope, site access and material selection.
What affects the price of roofing in St. Thomas
Quotes for the same roof can vary by 30% to 50% across London and Ontario because roofers are not pricing only shingles; they are pricing labour risk, access, tear-off difficulty, deck repair uncertainty, and seasonality. In St. Thomas, a simple bungalow in good condition may land near the low end of the $7,500 – $16,000 asphalt band, while a home with two layers of old shingles, soft decking, and lots of penetrations can push well above that once disposal and carpentry are added. The regional climate matters too: snow load and freeze-thaw cycling across Ontario and Alberta drive ice-dam protection requirements and heavier underlayment, Alberta’s hail belt pushes demand for impact-rated shingles, and coastal BC rain and wind favour metal and premium synthetic underlayment. Colder economic regions such as London, St. Thomas, and nearby communities also have shorter install seasons, so crews work harder during peak summer windows and labour rates rise when weather delays are common.
On a practical level, a steep roof on an older St. Thomas home can add a few hundred to a few thousand dollars because crews need more setup time, safety gear, and slower production. If hidden decking damage shows up after tear-off, you might add $500 – $2,500 for partial sheathing replacement before the new roof goes on. Chimneys, skylights, and multiple vents also raise labour because each flashing detail is a leak risk that needs proper integration. Homes built before 1981, which make up 57.7% of dwellings here (Statistics Canada, 2021 Census), are more likely to need these corrections, especially where past repairs were done cheaply. Meanwhile, ice-and-water shield coverage can increase a quote by a few hundred dollars, but that extra cost is usually justified in this climate; it is far cheaper than dealing with a leak after a January thaw. The point is that price differences are often driven by roof condition and climate readiness, not just contractor markup.
| Price Factor |
Why It Matters |
Cost Impact |
| Roof pitch and steepness |
Affects safety equipment and install speed |
Steeper roofs can add 10% to 20% for labour and safety setup |
| Number of shingle layers to tear off |
2 layers = extra labour + disposal |
Often adds $1,000 – $3,500 depending on area |
| Total roof area in squares (1 square = 100 sq ft) |
Bigger roofs need more material, labour and waste handling |
Each additional square typically adds $250 – $600 for asphalt systems |
| Decking condition |
Rotted OSB or plywood must be replaced |
Commonly adds $500 – $2,500 or more if widespread |
| Chimney, skylight and vent flashing complexity |
More penetrations mean more labour and leak protection |
Can add $250 – $1,500 |
| Ice-and-water shield coverage required |
Climate-driven eave protection for freeze-thaw and ice dams |
Usually adds $200 – $800 on a typical home |
| Regional labour rates and length of the install season |
Shorter seasons and peak demand increase contractor pricing |
Can shift a quote by 10% to 25% in the London market |
| Material quality tier |
Standard vs. impact-rated vs. premium systems change both cost and lifespan |
Upgrade from standard to premium may add $2,000 – $8,000 |
Permits & regulations in Ontario
In Ontario, most like-for-like re-roofing jobs do not require a building permit if you are simply removing worn shingles and installing a new roofing system on the existing roof shape. That said, a permit is often required if you are adding a second layer where the code or the roof structure does not allow it, repairing or altering the roof deck in a structural way, changing from a pitched roof to a flat roof, or modifying framing, trusses, and load-bearing components. If a contractor says “no permit needed” for major structural work, that is a warning sign. For a standard asphalt replacement in St. Thomas, the key is making sure the job is done to Ontario code with proper underlayment, eave protection, ventilation, and safe disposal.
Before signing, verify three things: Ontario licensing or business registration, liability insurance, and WSIB coverage. Start by asking for the legal company name and checking whether the business is registered and active online. Next, request a certificate of insurance showing current liability coverage, not just a verbal promise. Finally, ask for a current WSIB clearance letter or equivalent workplace coverage confirmation; this matters if a worker is hurt on your property. A reputable roofer will provide these documents without hesitation. For warranty-backed installs, confirm the manufacturer certification or approved installer status in writing, because some shingle warranties require certified installation to stay valid. In St. Thomas, where older roofs are common and weather windows are short, it pays to be cautious: a cheap quote is not a bargain if the contractor cannot prove they are properly covered and qualified.
Choosing the right roofing material for St. Thomas's climate
St. Thomas sits in a cold, continental climate where the roof has to handle snow load, freeze-thaw stress, and the occasional wind-driven storm, so material choice should be based on performance first and aesthetics second. Standard architectural shingles are usually sufficient for many homes here, especially if the roof has good ventilation, proper insulation, and strong ice-and-water protection at the eaves. They offer a balanced life cycle, reasonable maintenance, and resale appeal without the leap to metal pricing. Impact-resistant shingles are worth considering if your home is exposed, you want a tougher product, or your insurer offers a discount for upgraded storm-rated materials; even if the premium is 20% to 30%, the upgrade may make sense on a roof that would otherwise need replacement in the $11,000 – $22,000 range anyway. Metal roofing can be the smartest long-term option when you want lower maintenance, better snow shedding, and a 40+ year service life, but the upfront cost in the London market is significantly higher, often justified only if you plan to stay put or are dealing with repeated shingle failures. Flat membranes make sense only for low-slope sections, additions, and porches where shingles are not a good fit. If spending an extra $3,000 – $6,000 on metal avoids a second reroof in 20 years, the math can work; if you are planning to sell in five years, architectural shingles may give better value and stronger resale appeal.
| Material |
Lifespan |
Snow & Ice Performance |
Wind / Hail |
Maintenance |
Price Band |
| Asphalt 3-tab (entry-level) |
15–20 years |
Average; needs strong eave protection in St. Thomas |
Moderate wind resistance; weakest of the asphalt options |
Higher risk of curling and early granule loss |
$7,500 – $12,000 |
| Asphalt architectural / laminated (standard) |
25–35 years |
Good with proper ventilation and ice-dam detailing |
Better wind performance than 3-tab; fair hail resistance |
Moderate, with periodic inspection after storms |
$9,500 – $19,500 |
| Impact-resistant shingle (Class 4) |
25–40 years |
Very good; usually paired with upgraded underlayment |
Strong wind and improved hail resistance |
Low to moderate, depending on storm exposure |
$11,000 – $22,000 |
| Metal — steel panels (exposed fastener) |
30–50 years |
Excellent snow shedding; watch fasteners and seal points |
Strong wind resistance; good storm durability |
Low, but fasteners and sealant should be checked |
$18,000 – $28,000 |
| Metal — standing seam (concealed fastener) |
40–60+ years |
Excellent in snow and freeze-thaw conditions |
Excellent wind performance; premium storm resilience |
Very low; best long-term durability |
$24,000 – $38,000 |
| Flat TPO / EPDM membrane (low-slope only) |
20–30 years |
Good when drainage is designed correctly |
Good wind performance if fully detailed and flashed |
Moderate; seams and penetrations need inspection |
$12,000 – $30,000 |
How to choose a roofing contractor in St. Thomas
Choosing a roofer in St. Thomas starts with verification, not price. Ask for the company’s legal name and confirm they are operating in Ontario, then request proof of liability insurance and a current WSIB clearance letter. Check the insurance certificate directly with the broker if anything looks outdated. You should also ask whether the crew is manufacturer-certified for the system being quoted, because that can affect the product warranty. After that, get at least 2 to 3 itemised written quotes so you can compare labour, materials, underlayment, flashing, ventilation, disposal, and any carpentry separately. A lump sum is harder to assess, especially when one bidder has included ice-and-water shield at the eaves and another has not.
Read the scope carefully. Does the contractor include permit handling if one is required? Is disposal included? How many layers are being removed? What is excluded, such as rotten decking, chimney rebuilds, or skylight replacement? Ask for the workmanship warranty length and whether the manufacturer warranty is transferable to the next owner. In a market where homes often date from before 1981, a clean, documented scope matters more than a flashy sales pitch. Never pay more than 10% to 15% upfront, and hold the final payment until the job is complete, the site is cleaned up, and any punch-list items are finished. Get the start date and realistic completion window in writing, since weather delays are common in the London area.
- Confirm the legal business name and local contact information.
- Ask for a current certificate of liability insurance.
- Request a WSIB clearance letter dated within the current project window.
- Verify manufacturer certification for the proposed roofing system.
- Compare 2 to 3 itemised quotes, not lump sums.
- Check that tear-off, disposal, underlayment, and flashing are listed separately.
- Confirm whether permit work is included if needed.
- Ask how many shingle layers will be removed.
- Ask what decking repair allowance is included, if any.
- Get workmanship warranty terms in writing.
- Confirm transferability of the product warranty.
- Set a clear payment schedule and completion date.
Red flags in St. Thomas include a roofer who cannot show insurance or WSIB paperwork, refuses to itemise the quote, demands a large deposit, says “no permit ever needed,” pressures you to sign that day, or offers a price that is far below the local $7,500 – $16,000 asphalt range without explaining what is missing. Watch out for vague exclusions, no cleanup plan, and anyone unwilling to put start and finish dates in writing.
Frequently asked questions — roofing in St. Thomas
How do ice dams affect roofs in St. Thomas and how do I prevent them?
Ice dams are a real winter issue in St. Thomas because our cold, continental climate can produce freeze-thaw cycling along the eaves. Warm air leaks into the attic, melts snow on the roof, and that water refreezes at the cold edge, creating a dam that can force water back under shingles. The damage is often hidden at first: wet insulation, stained ceilings, and rot at the soffit or decking. Prevention starts with the roof system, not just roof raking. Good attic ventilation, proper ceiling insulation, sealed air leaks, and a continuous ice-and-water shield at the eaves are the standard fix. On an asphalt reroof, spending an extra few hundred dollars on proper eave protection is usually cheaper than paying for interior repairs later. In Ontario, that protection is especially important on older homes with uneven insulation or past patchwork upgrades.
What roofing warranty should I expect?
For a typical roof in St. Thomas, you should expect two warranties: a workmanship warranty from the contractor and a product warranty from the manufacturer. A solid workmanship warranty is often 5 to 10 years, though some reputable companies offer longer coverage on premium installs. Manufacturer warranties vary widely, and the fine print matters more than the headline years. Some cover materials only, while others include enhanced protection if the installer is certified and the full system is installed correctly. If you are paying for an asphalt replacement in the $7,500 – $16,000 range, ask whether underlayment, starter strip, vents, and flashing are all part of the warranty-backed assembly. Also ask if the warranty is transferable, because that can help resale value in Ontario’s older housing market.
Is metal roofing worth the extra cost in St. Thomas?
Metal can be worth it in St. Thomas if you plan to stay in the home long enough to benefit from the longer service life, or if your roof gets hammered by repeated freeze-thaw and snow load issues. The upfront price is usually much higher than asphalt, often in the $18,000 – $38,000 range, but the maintenance burden is lower and the roof can last 40 to 60 years or more. For homeowners in older neighbourhoods with steep pitches or recurring shingle wear, metal can make sense because it sheds snow well and handles winter stress better. If you are selling in a few years, though, architectural shingles may provide a better return on investment because buyers often value condition and curb appeal more than a premium roof they may not fully recover in the sale price.
What time of year is best to replace a roof in St. Thomas?
In St. Thomas, late spring through early fall is usually the best window for roof replacement because temperatures are more stable and crews can work safely and efficiently. Shingles seal better when the weather is warm enough, and there is less risk of moisture-related delays. That said, good roofers still work into the shoulder seasons when needed, especially if a home is leaking and waiting would cause more damage. Winter jobs can be done, but they are slower, more expensive, and more weather dependent in the London area. If your roof is nearing the end of its life, book early because the best crews fill up quickly. A planned summer replacement is usually easier to schedule than a last-minute emergency repair that can quickly climb into the $350 – $3,500 repair range or higher if hidden damage is found.
How do I compare roofing quotes fairly?
To compare roofing quotes fairly in St. Thomas, make sure each contractor is pricing the same scope. That means the same tear-off depth, the same underlayment, the same ice-and-water shield coverage, the same flashing details, and the same disposal plan. If one quote is much lower, find out what was left out. Ask for itemised line items for labour, materials, ventilation, decking allowance, and cleanup. Confirm whether permits are included and whether the workmanship warranty is identical. A quote for a standard asphalt reroof near the $7,500 – $16,000 band should not vary wildly unless one contractor is adding premium components or another is cutting corners. On older St. Thomas homes, hidden decking replacement or two-layer tear-offs are often the real difference, so compare those assumptions carefully before you choose.
Should I repair or replace my roof in St. Thomas?
The decision comes down to roof age, leak frequency, and how much of the system is failing. If the damage is localized, such as a small flashing failure or a few lifted shingles, a repair in the $350 – $3,500 range may be the right move. But if the roof is nearing the end of its life, has multiple leaks, curling shingles, soft decking, or two layers already in place, replacement usually makes more financial sense. In St. Thomas, older housing stock is common, and many roofs built before 1981 are simply too tired for repeated patching to be cost-effective. A full replacement also gives you the chance to fix ventilation, improve ice-dam protection, and reset the warranty clock. If you are seeing interior staining after each thaw, replacement is usually the smarter long-term choice.
