Succeeding with Your Vinyl Window Installation in Markham

Vinyl Window Installation in Markham: How to Hire the Right Installer

The window you buy matters less than the person who puts it in. A top-rated vinyl window installed badly can leak cold air and start rotting the wood around it within a few winters. A mid-range window installed properly can give you decades of reliable service.

I've been doing this since 1989, and most of the window problems I get called out to fix aren't product failures. They're installation failures.

This guide is for Markham homeowners considering vinyl window replacement or installation. Proper installation ensures your windows perform well, last longer, and protect your home from the elements. It covers how to pick a window installer you can trust and what a proper vinyl window installation looks like, so you can check the work once the crew packs up.

What Makes a Good Vinyl Window Installation?

A good vinyl window installation seals out water and cold air for decades while the window keeps opening and closing easily.

In York Region, that job is harder than it sounds. Our windows go through dozens of freeze-thaw cycles every winter. Water that sneaks into a small gap freezes and pries the gap a little wider each time. Lake-effect snow and spring rain then find their way into the wall. That's why the parts of the job you can't see after the trim goes on, like the foam and flashing, decide how long your new windows last.

How to Choose a Window Installer in Markham

Start with the company, then check the installation process. A trustworthy company with a sloppy crew still gives you a bad result, so you need to look at both.

How long has the company been in business?

Look for at least five years, and longer is better. A bad installation can stay hidden for years before the drafts and water stains show up. Some installers know this. They cut corners and undercut honest contractors for a few seasons, then close up shop before the callbacks start.

If a company has been around for less than three years, check their references closely and ask them to walk you through every installation step listed later in this article, especially if they also offer broader exterior home improvement services like roofing, doors, or siding.

Do they have a showroom you can visit?

A real showroom is a good sign a company plans to stick around. It also lets you see the actual replacement windows, open and close display units to judge ease of access and how much natural light different styles bring in, and compare glass packages before you commit. Our showroom is at 3400 14th Avenue, Unit 28, in Markham, and you're welcome to drop by.

How long is the warranty on window installation?

Look for a labour warranty of at least five to 10 years from the installer, on top of the manufacturer's warranty, since many vinyl windows come with a 25-year warranty. Product coverage often includes manufacturing defects such as warping and seal failure. These are two separate things. Some companies offer a better deal by also including coverage for installation and service, so homeowners should confirm exactly what is covered, no matter the wording. The manufacturer covers the window itself, like the sealed glass and hardware. The installer covers the work, like leaks around the frame or a sash that won't close.

A long labour warranty from a long-standing company tells you something. If they did poor work, they'd spend all their time going back to fix old jobs. To make sure a company honours its warranty, call a few past customers and check their reviews and Better Business Bureau rating.

Are they insured and covered by WSIB?

Every window installer you hire should carry general liability insurance and be in good standing with WSIB, Ontario's workplace insurance board. Ask for a certificate of insurance and a WSIB clearance certificate before work starts.

Insured contractors who follow safety rules have higher costs, and that often explains why their quote is higher than the cash-only guy down the street. If an uninsured worker falls off a ladder at your house, sorting it out can become your problem.

Who will actually install your windows?

Ask whether the company uses its own installation team or hands the job to subcontractors. An in-house crew can better coordinate the work and minimize disruptions during window replacement to ensure a smoother process. Neither answer is automatically wrong, but you want to know who's responsible if something goes wrong. A company that stands behind its crew will tell you plainly.

What Questions Should I Ask a Window Replacement Company?

The section above helps you vet the company. These questions help you vet the job itself and make a more informed decision about the company and the job, so bring this list to every quote:

• How long have you been installing windows, and do you also handle windows and doors installation in Markham or York Region?

• How long is your labour warranty, and what does it cover?

• Can I see your certificate of insurance and WSIB clearance certificate?

• Will your own installers do the work, or a subcontractor?

• Will you do a retrofit or a full-frame installation, and why?

• What kind of foam do you use around the frame?

• Do you install a drip cap above each window?

• If you find rot after the old window comes out, who pays to repair it, and how is that priced?

• How do you dispose of the old windows?

• How long will the job take, and who is my contact person if there's a problem afterward?

A good installer will answer all of these without getting defensive. If someone dodges the questions about foam and flashing, keep looking.

Retrofit vs. Full-Frame: Which Type of Installation Do You Need?

A retrofit installation slides the new window into your existing frame. A full-frame installation, which we often call brick-to-brick in Markham, removes the old windows down to the rough opening and starts fresh.

Retrofit is faster and costs less. It works well when the existing frame is solid and dry. The trade-off is that you lose a little glass area, and you can't see what's happening inside the wall.

Full-frame costs more, but it lets the installer check for rot before insulating and flashing the whole opening properly. If your old wood frames are soft, or you've seen water stains under a window, full-frame is usually the right call. Many 1970s and 1980s brick homes in neighbourhoods like Unionville and Markham Village are good candidates for brick-to-brick work.

How Are Windows Installed? The Steps a Good Installer Follows

Vinyl windows are installed by removing the old unit, setting the new frame plumb and level on shims, fastening it through the side jambs, sealing the gap with foam, and protecting the outside with flashing and caulking.

Below is how we typically handle a replacement install on a Markham home. Details like shim spacing and fastener placement can vary by window, so the manufacturer's installation instructions always come first. Use these steps as a guide for what to ask about, and expect a good installer to explain any differences.

1. Remove the old window and prep the opening

The installer takes out the old window and checks the opening for rot or soft wood. Any damage gets repaired before the new window goes in. Covering up rot is one of the most expensive shortcuts you can pay for.

2. Set the window plumb, level, and square

Before setting the unit in the opening, confirm the window is the correct size to determine a proper fit, then shim it so it sits level, plumb, and square. Plumb means perfectly vertical, level means perfectly horizontal, and square means all corners are 90 degrees. As a rule of thumb, we place a shim about every 16 inches along the sill and about every 24 inches on the side jambs. A window that's even slightly out of square will bind and leak air at the corners.

3. Fasten through the side jambs

The frame is fastened through the jambs at each shim location using round-head, rust-resistant screws. On this type of replacement install, we avoid fastening through the sill, because a screw there can interfere with drainage and give water a path into the wall.

4. Insulate the gap with low-expansion foam

It’s essential to apply low-expansion foam insulation around vinyl windows during installation, so we apply two beads of low-expansion polyurethane foam about one inch deep around all four sides of the frame. One bead goes along the outside edge, right behind the brickmould. The other goes near the inside edge. If the jamb extensions aren't sealed to the frame, the foam should cover that joint too.

Low-expansion is important because vinyl frames require it to avoid damage. Regular spray foam from the hardware store can swell enough to bow a vinyl frame and jam the sash.

5. Install a drip cap above the window

A drip cap is a small piece of metal flashing that sits above the head of the window and sheds rain away from the top of the frame. Ontario's building code calls for flashing over most window openings in exterior walls, and good installers treat it as standard practice. The back leg of the drip cap should tuck up behind the building paper so water can't run in behind it.

This is the step I see skipped most often, and it's one of the main reasons windows leak after a few years.

6. Seal the outside with brickmould and caulking

The gap around the outside of the window gets covered by vinyl brickmould, which is usually built into the window, or by aluminum capping. Then the installer runs a bead of quality exterior-grade caulking where the brickmould meets the brick or siding. Every gap should be sealed and protected from the weather.

7. Finish the interior

Inside, the installer adds jamb extensions and trim, then checks that every sash opens and locks smoothly. A good crew also leaves the interior clean and hauls away the old windows before they leave, and the finished vinyl window is highly durable and needs very little ongoing maintenance.

Should You Nail the Top Flange of a Window?

Follow the window manufacturer's instructions, because they vary. Many vinyl window makers want the top fasteners left slightly loose, or set in slotted holes, so the header above can settle without squeezing the frame. Nailing the top flange tight can make the window hard to open later.

This mostly applies to new-construction windows with a nailing flange. Most replacement windows going into existing Markham homes are screwed through the side jambs instead, as described above.

How Can You Tell If a Window Is Installed Correctly?

A properly installed window opens and locks without force, the gaps between the sash and frame look even all the way around, and it should also help reduce outside noise because tight seals and thick framing materials stay evenly compressed. Here's what to check once the crew is done:

• Open and close each window fully. It shouldn't stick or need an extra push to lock.

• Look at the reveal, the gap between the sash and frame. It should be even on all sides.

• Check outside for a continuous bead of caulk with no gaps or smears.

• Look for a drip cap above each window.

• On a windy day, slowly run your hand around the trim and frame to feel for drafts.

• Watch for water or frost on the inside of the frame after the first heavy rain or cold snap.

If something feels off, call the installer right away. Small fixes are easy in the first few weeks and much harder after the trim has been painted, and an expert can help you decide whether a problem window should be repaired or replaced.

What Are Common Window Installation Mistakes?

Skipping the Drip Cap

One of the most common mistakes is skipping the drip cap. This crucial piece of flashing helps prevent water from seeping into the wall above the window. Without it, leaks are much more likely to develop after a few years.

Using the Wrong Foam

Another frequent error is using the wrong type of foam. Regular spray foam can expand too much, bowing the vinyl frame and causing the sash to jam. Always use low-expansion foam specifically designed for windows.

Improper Fastening and Shimming

• Screwing through the sill, which blocks drainage

• Shimming only at the corners, which lets the frame sag in the middle

Relying on Caulk Alone

Depending solely on caulk to keep water out is a mistake. Proper flashing and foam insulation are essential for a long-lasting, leak-free installation.

Covering or Ignoring Rotted Wood

• Covering rotted wood instead of repairing it

Incomplete Insulation

• Leaving gaps in the foam that let cold air pour in around the trim

Rushing the Job

• Rushing the job and never checking how each window operates

Almost every one of these is invisible once the trim is on. That's why choosing the right installer matters more than any brochure feature.

How Much Does Vinyl Window Installation Cost in Markham?

Most Markham homeowners pay between $500 and $1,200 per window for vinyl replacement windows, including professional installation, though total replacement costs depend heavily on the number of windows being replaced. Here's roughly how that breaks down:

• The window itself: $200 to $600 for a standard vinyl unit, depending on size and glass package

• Installation: $150 to $400 per window

• Full-frame (brick-to-brick) work and rot repair: These push a window toward the top of the range or past it

For a whole-home project with multiple openings, costs can run around $22,000 depending on scope.

Large bay windows and bow windows cost more. Upgrading to triple-pane glass adds a bit to the price but can end up saving money over time through lower heat loss, and vinyl is typically more affordable than wood, fibreglass, or aluminum. For a full breakdown, see our guide on how much it costs to replace a window in Markham and our detailed page on window replacement in Markham.

Once your custom windows arrive, most homes are completed in one to two days.

Is there a rebate for new windows in Ontario?

Yes, for now. Ontario's Home Renovation Savings Program pays $100 per window or door rough opening for ENERGY STAR certified products, and homeowners comparing windows and doors should expect a front door replacement to cost about $3,000, with a minimum number of openings required. You need a home energy assessment first, and windows have to be paired with at least one other qualifying upgrade, like insulation. The program is scheduled to run until November 30, 2026, so check the program site before you plan around it.

Can You Install Vinyl Windows Yourself?

You can, but for most homeowners it isn't worth the risk. DIY installation saves the labour cost, but a poor install can void the manufacturer's warranty and leave you with air leaks you can't easily fix. Buying windows yourself and hiring someone else to install them has its own catch. If a window leaks, the supplier and the installer can each blame the other, and you're stuck in the middle.

If you're handy and replacing one basement window, go for it. For a full house of replacement windows, hire a professional.

When Is the Best Time to Install Windows in Markham?

Any season works when the product and installation are suited to local weather. Fall and winter can be easier times to schedule, because demand is usually lower than during the spring and summer rush, and many projects can still be completed within a week, and there are specific advantages to installing windows and doors in winter. High-quality vinyl windows are moisture-resistant and will not rot, warp, peel, or corrode, and they can last 30 years or more without peeling or cracking even in harsh weather. A good installation team works one opening at a time, so each room is only open to the cold for a short while.

Talk to Edmunds About Your Vinyl Window Installation

You now know what a good installation looks like and how to check one. If your windows are fogging up or letting in drafts, Edmunds Home Improvements can inspect your current windows, recommend energy-efficient vinyl windows where appropriate, explain style options such as casement or double-hung, and provide an honest recommendation with a written quote that can help lower heating and cooling costs. You can also look through our home improvement project examples to see the kind of exterior work we do. We've been serving Markham homeowners since 1947, and our reputation helps deliver peace of mind, so rest assured some warranties also include coverage for installation and service.

Learn more about our window installation service in Markham, or contact Edmunds at 905-472-0276 to book a free in-home estimate. We're happy to look at any roofing or other renovation questions while we're there, and vinyl's multi-chambered frames help reduce heat transfer while the material never needs scraping, painting, or staining.