Siding is the most visible component of your home’s exterior — and the most complex to install correctly. Done right, it protects the building envelope, manages moisture, and lasts 30–50 years. Done wrong, it traps moisture behind the cladding, accelerates rot in the sheathing, and fails in ways that are expensive to diagnose and repair because the damage is hidden until it’s severe.

The questions that matter most about siding aren’t about the color or the profile. They’re about what goes behind it and how it’s installed.

“I’ve been called in to replace siding that was only six years old because the crew that installed it didn’t use house wrap, didn’t flash the windows properly, and didn’t leave adequate clearance at the base. The homeowner had no idea because it looked fine from the street. Moisture had been working behind those panels for years. The questions to ask about siding are mostly the questions about what you can’t see once it’s on.”

— Gentian from Siding Solutions and Gutters., certified exterior cladding specialist and renovation consultant with 15 years of experience in residential siding installation across the Greater Toronto and Hamilton areas

Questions About the Product

What type of siding are you recommending, and why?

There are several major siding categories available for Canadian homes:

Vinyl siding is the most common residential cladding — low maintenance, resistant to rot and insects, and available in a wide range of profiles and colors. Quality varies enormously by gauge (thickness). Entry-level vinyl at 0.040″ is noticeably more prone to warping, cracking, and fading than premium vinyl at 0.046–0.048″. Ask specifically what gauge is being quoted.

Engineered wood (fiber cement or composite) products like James Hardie or LP SmartSide offer a more traditional wood look with superior impact resistance and fire ratings. They require more maintenance (painting) but perform exceptionally well in Canadian climates. Ask about the painting schedule and whether the product comes pre-primed or pre-finished.

Aluminum siding is less common today but still installed on many homes. It’s durable and recyclable but dents more easily than vinyl and requires painting over time.

Wood siding (cedar, pine) is a premium option requiring ongoing maintenance — painting or staining every 5–10 years. In the right hands, it’s beautiful and long-lasting. Installed poorly or neglected, it fails quickly.

Ask the contractor what they’re recommending for your home, your climate, and your maintenance tolerance — and ask for specifics, not just the category.

What a good answer looks like: A specific product name, gauge or thickness, warranty class, and a clear rationale for why it’s appropriate for your home.

What is the shingle or panel warranty?

Premium vinyl siding typically carries a 40–50 year limited warranty, with some manufacturers offering lifetime coverage. Fibre cement products like James Hardie carry a 30-year limited warranty. Ask what the warranty covers — fading, cracking, peeling — and what the conditions are for the warranty to remain valid.

Are you a certified installer for this product?

Many siding manufacturers — particularly fiber cement brands like James Hardie — require installation by certified contractors to qualify for enhanced warranty coverage. Ask whether the contractor holds current certification for the products they’re recommending.

Questions About What Goes Behind the Siding

Will house wrap be replaced or inspected?

House wrap (or building wrap) is the moisture barrier installed between the sheathing and the siding. It allows water vapor to escape from inside the wall while preventing liquid water from getting in. If existing house wrap is being reused, ask when it was installed, what condition it’s in, and whether it meets current standards.

On a full siding replacement, house wrap should be replaced as standard — not reused.

What a good answer looks like: New house wrap specified as standard on a full replacement, with the brand and type named.

How will windows and doors be flashed?

Flashing at window and door openings is the most critical installation detail in siding work — and the most commonly skipped on budget jobs. Without proper flashing, water infiltrates at every opening and works its way into the wall assembly behind the siding. Ask specifically how each window and door will be flashed, and with what material.

What a good answer looks like: A specific flashing method described clearly — self-adhering flashing tape at sills and jambs, integrated with the house wrap, before siding panels go on.

Will the sheathing be inspected, and how is damage handled?

When old siding comes off, damaged or rotted sheathing may be exposed. Ask how this is handled: will the contractor stop and show you any damage before repairing it? Is there a pre-agreed per-sheet price for sheathing replacement? This should be in the quote before work starts.

What a good answer looks like: A specific per-sheet price for sheathing replacement, agreed upfront, with a commitment to document and show any damage before proceeding.

What clearance will be left at the base?

Siding requires minimum clearances at the bottom — typically at least 6 inches above grade, 1–2 inches above flat surfaces like decks and walkways — to prevent moisture wicking and insect infiltration. Ask the contractor what clearances they’ll maintain and confirm it meets the manufacturer’s installation requirements.

Questions About the Installation

How will inside and outside corners be handled?

Corners are one of the most visible installation details on any siding job. Ask whether corners will be finished with J-channel (a less premium look), corner posts (more finished), or a mitered wrap. The answer tells you about both the aesthetic quality and the care taken with weatherproofing.

How will the base and top of the wall be treated?

Ask about starter strips at the base, undersill trim at windows, and how the siding will terminate at the top — whether under soffit, at a frieze board, or at a different cladding material. These transitions are where water gets in when they’re not done carefully.

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