When roofing quotes are far apart, check what each includes before comparing the totals. Tear-off, flashing replacement, deck repairs, and ventilation can change the price substantially. This guide explains how to request comparable quotes; it does not provide a verified GTA market-price range. The lowest total is only useful once you know what it buys.
Which measurements does a roof estimate need?
Living area is not roof area. A compact two-storey, a wide bungalow, and a house with dormers can have similar interior square footage and completely different roof surfaces. Pitch, valleys, hips, access, number of existing layers, material disposal, skylights, chimneys, low-slope sections, and the condition of the deck all change the work.
A measured roof plan and site inspection establish the quantities and visible conditions. Ask which parts of a preliminary estimate remain provisional.
What should every roof quote include?
| Line item | What should be written | Why it changes cost |
|---|---|---|
| Measurement | Roof area, pitch, slopes, valleys, ridges, and penetrations | Defines material quantity and labour |
| Removal | Number and type of existing layers, disposal, and site access | Multiple layers and difficult access add handling |
| Deck | Inspection method and unit rate for approved replacement | Hidden damage cannot be confirmed before removal |
| Water management | Eave membrane, field underlayment, valleys, drip edge, and flashings | Different scopes can look identical in the final total |
| Roof covering | Exact manufacturer, product, colour, accessories, and fastening system | Products and warranty systems are not interchangeable |
| Completion | Ventilation work, protection, cleanup, taxes, schedule, and warranties | These are part of the job even when a quote forgets them |
What changes the total most?
Geometry and access usually move labour first. A steep or cut-up roof needs more setup and slower material handling than a simple gable. Tight driveways, protected landscaping, neighbouring walls, and limited bin access also matter. Include access and disposal arrangements in the quote.
The existing assembly can move the scope even more. A full tear-off may expose damaged deck boards, obsolete flashings, blocked intake ventilation, disconnected exhaust ducts, or a low-slope section that needs a different roofing system. Those conditions should be documented, explained, and approved before extra work begins.
How should hidden deck repairs be priced?
No contractor can honestly confirm the entire deck through finished roofing. The contract should say how the exposed deck will be checked, show a unit rate for approved replacement, and require photos or owner approval before the allowance grows. Owens Corning's roof-deck preparation instructions require a dry, smooth, structurally sound deck. Resolve damaged decking before installing the new roof system.
Do asphalt, metal, and cedar quotes include the same work?
They should cover the same house, but not pretend the assemblies are identical. Asphalt quotes should identify the complete manufacturer system and warranty conditions. Standing-seam metal quotes need the panel, substrate, coating, seams, clips or fasteners, trims, penetrations, and snow-management review. Cedar quotes need grade, treatment, exposure, fasteners, ventilation, valley, and underlayment details from the Cedar Shake & Shingle Bureau manual. Our material comparison explains the homeowner tradeoffs without mixing them into the quote math.
What should the contract say before work starts?
Ontario's home-renovation consumer guidance says to get written estimates with itemized products and services and include the selected estimate in the contract. When an estimate is part of the contract, the final price generally cannot exceed it by more than 10% unless you agree to new work or a new price. The contract should also state schedule, payment terms, cleanup, warranties, subcontractors, and responsibility for permits.
Do not accept ‘standard roofing package’ as the material description. Write down the exact products, quantities or measured scope, exclusions, deck-repair process, and change-order rule. If a detail matters while comparing quotes, it matters enough to survive into the contract.
How do you compare three roofing quotes fairly?
Normalize the scopes first. Ask each contractor to clarify missing lines and separate optional work from required work. Then compare the exact assembly, repair allowances, schedule, warranty, and total. Ontario's guide to hiring a roofer also recommends written estimates and a detailed contract. Our roofing and siding service follows the same scope-first approach.
