How to Hire a Siding Contractor in Ontario: The Questions, the References, WSIB and Insurance, Deposits, Manufacturer Training and the Paper a Good Crew Hands Over Without Being Asked

Exterior Finishes

Hiring a Siding Contractor: The Wall Will Hide His Work for Thirty Years, So Do the Looking Before He Starts

Siding is the one trade where the finished job tells you almost nothing about the quality. Vinyl nailed too tight, fibre cement cut and left unprimed, a window with no sill pan, all of it looks perfect from the driveway on the day the invoice arrives and shows up as a ripple or a stain years later. So the hiring is the inspection. The questions below are the ones I would ask any crew before letting them on a wall I was responsible for, and the paper at the bottom is what a good crew produces without a fuss.

Ontario rules and Central Ontario practice, checked October 2026. Applies to siding, stucco, stone and eavestrough contractors alike.

Eight questions, and what the answers tell you

  1. Who measured the house, and what did you get? A contractor who quotes without measuring is guessing, and the guess is in his favour. The answer is a net wall area per elevation, which you can check against your own tape.
  2. What goes on the wall before the siding? The right answer names a sheathing membrane, how it laps, flashing at every opening, and whether this product wants a rainscreen gap. “The old wrap is fine” is an answer too, if he has seen it.
  3. What is your rate if the sheathing is rotten? He should have one, in dollars per square foot and per opening, and he should expect to find some on any house over 25 years old. “We will see” is a change order with your name on it.
  4. How do you nail vinyl, and how do you cut fibre cement? Vinyl: loose, head 1/32 in. off the panel, centred in the slot, every 16 in., so it can move. Fibre cement: shears or a dust-collecting saw, cut ends primed, 6 in. off the grade, 2 in. off a roof. He should say this without looking it up. If he does not know the manufacturer’s sheet, the warranty is already gone.
  5. Who is on the ladder, and are they yours? Employees or subs, and whether the same crew that quoted will do the work. A salesman who hands the job to whichever crew is free is a different business.
  6. Can I see a job from three years ago? Not last month’s. Three winters in, where the panels have moved and the caulking has done whatever it is going to do.
  7. What is your workmanship warranty, in writing, for how long? Two years is common for siding labour, five is good. The product warranty is a separate thing and the contractor registering it for you is a small sign of a crew that has done this before.
  8. What is the payment schedule? Something like 10% on signing, draws at stages you can see, 10% held back. Anything front-loaded is financing the contractor’s last job with your money.

References: visit, do not phone

A phone reference is a nice person saying nice things. A visit to a three-year-old job is a wall. Stand back and look along the siding in low sun for waves and ripples, which on vinyl means tight nailing and on fibre cement means a wavy substrate nobody strapped. Look at the bottom course: 6 in. off the grade, straight, and not buried in the garden. Look at a window: is there a visible head flashing above the trim, and is the caulking at the sides and not across the bottom? Look at the butt joints on fibre cement for the flashing tab behind each one. Then ask the owner the one question that matters: when something came up, how fast did he come back?

Ask for one reference from a job that went wrong. Every contractor has one. The ones who will tell you about it and what they did are the ones you want.

The paper: WSIB, insurance, HST, the contract

WSIB clearance certificate. In Ontario, construction contractors have to be registered with the WSIB and you can check a clearance certificate online by business name before anyone climbs a ladder. Without it, an injured worker on your property can become your problem. A crew that says it is “all covered under my own insurance” is either a one-man shop with an exemption, which is possible, or not covered. Ask to see the certificate; it takes thirty seconds to produce.

Liability insurance. A certificate of commercial general liability, $2 million is the usual number, naming the contractor, with a current date. Call the broker on the certificate if the job is big. A dropped ladder through a bay window or a grass fire from a saw is what it is for.

HST number. On the quote and on the invoice. A contractor doing $30,000 jobs for cash with no HST number is a contractor who will not be there for the warranty, because on paper he was never there at all.

The contract. Ontario’s consumer protection law requires a written contract for any home renovation over $50, and an estimate cannot be exceeded by more than 10% without your written agreement. If the contract was signed at your door rather than at his office or yours by appointment, you have a 10-day cooling-off period to cancel it in writing for any reason. What the contract itself should say is on the exterior renovation contract checklist, and the payment rules under the Construction Act, holdback and prompt payment both, are there too.

Manufacturer training and what it is worth

James Hardie runs a contractor program, LP runs one for SmartSide, the Vinyl Siding Institute certifies installers against its manual, and the EIFS and stucco makers train applicators on their systems. None of it is a guarantee. All of it means the crew has at least read the installation sheet once, and on fibre cement in particular, where the clearances, the primed cuts, the flashing behind every butt joint and the no-caulk-at-the-laps rule all come from that sheet, that is worth something. A warranty claim on fibre cement starts with the manufacturer’s inspector reading his own instructions back to the installer, and the trained installer is the one who followed them.

Fibre cement is a good product that is hard to install: heavy, dusty, brittle on the edges, fussy about its gaps. The cheap fibre cement quote is the one to worry about, because the only way to install it cheaply is to install it wrong. Stucco is the same conversation with a different sheet; the stucco hub covers what a stucco crew should know, and the brick and stone hub covers the masons.

Deposits, and the one number that ends the interview

A deposit buys material and holds a slot in the schedule. On a $40,000 siding job, 10% is $4,000, and the siding itself is not ordered until the colour is signed off, so even that is generous. Progress draws should follow things you can see: wall stripped and wrapped and flashed, siding on, trim and cleanup done. The last 10% is holdback under the Construction Act, which you are required to keep for 60 days after the job is finished so that a supplier or sub who was not paid has something to lien against other than your house. A contractor who asks for 50% down is telling you he cannot buy the siding for your job without your money, which means the last customer’s money went somewhere else. End the interview politely.

One honest note about this site. I build ICF houses and finish most of them in stucco, stone and siding, but I do not have a siding, stucco or masonry sub I can hand you across Ontario, and I will not pretend to. The $99 quote review and the $249 takeoff are what I sell, and they work anywhere. If you are in Simcoe, Muskoka or the Georgian Bay area and send the request-a-quotation form, it comes to my office and I sort it out from there. Everyone else, the quote comparison grid and this page are the tools, and they are enough.

Questions people ask

How much deposit should a siding contractor ask for?

About 10%, with the balance in draws at stages you can see and 10% held back for 60 days after completion under the Construction Act. 50% down is a reason to keep looking.

Does a siding contractor in Ontario need WSIB?

Yes, construction contractors with workers must be registered, and you can check a clearance certificate online by business name. Some sole proprietors with no employees are exempt; ask which it is and get it in writing.

What insurance should a siding contractor have?

Commercial general liability, usually $2 million, with a current certificate you can verify with the broker, plus WSIB coverage for the workers. Your own home policy does not cover his crew.

Do I need a permit to replace siding in Ontario?

Usually not for like-for-like siding with no structural change. Adding masonry, changing openings or adding exterior insulation that changes the wall assembly can need one; ask your municipality before the quote, and get the answer in writing if the contractor says no.

What is a manufacturer-certified siding installer?

A contractor who has taken the maker’s training on that product and is listed by them. It is not a guarantee of workmanship, but it means the installation sheet the warranty depends on has been read, which on fibre cement is most of the battle.

Can you recommend a siding contractor near me?

No, and I would be suspicious of a website that says it can for all of Ontario. I review quotes and do takeoffs. In my own area the quotation form comes to my office. Elsewhere, the eight questions above and a reference visit will find you a good one.

Hire with the number in your hand

Run your house through the exterior cladding cost calculator before the first contractor comes, so the interview is about his lines and not his total. Then send the quotes you get to the $99 review and let me read them against the same list.

Price my job firstReview my quotes, $99

Sources and further reading