Window and Door Replacement London: How to Navigate Permits and Codes

Posted on 2026-06-13 11:22:33

When people talk about upgrading a house in London, Ontario, they often start with windows and doors. It makes sense. New units cut drafts, tame street noise, sharpen curb appeal, and in many cases lift resale value more than a fresh coat of paint ever could. What trips up homeowners is not the shopping, it is the rules. The Ontario Building Code sets the baseline for safety and performance, and the City of London adds its own procedures on top. Knowing where those lines are will keep your project moving, your budget intact, and your sleep easier.

I have sat at kitchen tables with homeowners who assumed a window swap was a quick Saturday job, only to discover they were changing bedroom egress or enlarging a front opening. I have also worked with careful clients who pulled a permit they did not need, costing time and fees. The sweet spot is understanding what triggers a permit, what documentation helps plan examiners say yes on the first review, and what inspections you should expect. That is the ground we will cover, with practical examples from real projects in London.

What counts as “replacement” and what counts as “alteration”

Contractors and municipalities use these words differently. In the market, window and door replacement London usually suggests full frame removal and a new unit. From the City’s point of view, the key question is whether you are changing structure, safety, or performance requirements.

If you remove a window and slide in a new unit the same size, keeping the rough opening intact, you are typically in the clear. The same is true if you swap a worn slab for a new slab in the same door frame. The moment you widen or raise an opening, introduce a new opening where there was none, convert a window into a door, or touch a wall that acts as a fire separation, you have stepped into alteration. Alteration is where permits and inspections start. There are also trigger points for egress, tempered glass, and energy labeling even when the opening size stays put.

I have seen this get fuzzy when a client chooses a thicker factory-mulled window, or a door with larger sidelites. If the rough opening grows by a few centimetres and you need to trim a stud, that is a structural change. Plan Additional info for a permit.

When the City of London expects a permit

Rules evolve, but the City’s position has been steady for years. You should always confirm with Building Services, yet these are the recurring scenarios that have required permits on projects I have managed in London.

Creating a new window or door opening in any wall Enlarging or reducing an existing opening Converting a window to a door, or a door to a window Replacing or altering a door or window in a fire rated or fire separated wall, including between a house and an attached garage

If you are in a heritage conservation district or your home is listed or designated, you will often need a heritage alteration permit even if the work might otherwise be exempt. In those cases, design details matter, such as muntin patterns, sightlines, and materials visible from the street. I have had heritage staff sign off on aluminum-clad wood windows where vinyl would have been rejected, even though both met the energy targets.

For like-for-like swaps that do not touch structure or fire separations, a building permit is generally not required in London. That does not mean anything goes. You still need to comply with the Ontario Building Code for safety glazing and bedroom egress, and with product labeling standards.

The code rules that shape design decisions

Most surprises arrive not from whether you need a permit but from the technical standards that govern what you can install. A few have outsized influence on window and doors London Ontario projects.

Bedroom egress windows

Any bedroom without a sprinkler system needs an egress window. The Ontario Building Code requires a minimum unobstructed opening of 0.35 square metres, with no dimension less than 380 millimetres. That is the clear opening through which a person can crawl, not the rough opening size on your quote. If you are replacing a casement window with a slider in a basement bedroom, you may lose precious clear space because sliders tend to keep more frame in the opening. Many projects stall here. I keep a tape measure and manufacturer cut sheets handy to run the numbers before anyone orders.

If the window opens into a well, you need at least 760 millimetres of clearance from the face of the window to the well wall. If the sash could project into that space, the code expects a hinged cover or enough room to swing the sash clear. I have watched crews discover a 600 millimetre window well after the unit arrives. That is a bad day.

Safety glazing near doors and tubs

Tempered or laminated glass is required at hazardous locations. The rules are technical, but two common cases apply to many London window and door jobs. First, glass in or immediately beside a door. If the glazing is within 300 millimetres of the door edge and within a typical human impact zone, you will likely need safety glazing. Second, glazing around showers or tubs. Within about 1.5 metres horizontally, tempered glass is the default. This matters if you are adding a larger bathroom window above a tub or replacing a full-lite door that opens to a deck. I specify tempered sidelites on nearly every steel door installation London Ontario project with a narrow sidelite. It is safer and avoids a last minute change order.

Doors between house and garage

The door from the house to an attached garage is not an ordinary exterior door. It is part of a fire separation. The slab must be rated at not less than 20 minutes, be weatherstripped, and be equipped with a self-closing device. Decorative glass is generally not permitted in that location unless the assembly is tested and labeled accordingly. When clients ask for a full-lite door between the mudroom and garage, I steer them to solid or limited vision options rated for the application, or we rework the plan.

Fall protection at upper storey windows

On the second floor and above, bedroom windows need limiters or opening control devices if the sill is low enough to present a fall risk. You can often use manufacturer supplied limiters that cap the initial opening to 100 millimetres, with a release mechanism available for cleaning or emergency egress. If a client insists on a low-sill picture window in a child’s room, I flag this early. The fix is simple when planned, annoying when missed.

Energy performance and labeling

New windows and doors in Ontario generally need to meet energy efficiency targets under SB-12 of the Ontario Building Code. For typical low-rise homes in London, the most common route is to select units with an Energy Rating or U-factor that complies with the compliance package your builder or energy advisor uses. For renovations, inspectors often check that the product carries a Canadian Standards Association or NFRC label showing compliance. I have yet to see an inspector in London argue about a reputable label, but I have seen projects delayed when import units arrived without Canadian labeling. For the sake of smooth inspections, I prefer models certified to NAFS-08 or newer, with climate-appropriate performance.

Structural lintels and point loads

Any enlargement of an opening means someone has to do the math for the lintel. In older North London homes, I have found undersized wood lintels carrying brick veneer and floor loads. When we widened a living room window by 300 millimetres, the structural review led us to a two-ply LVL with proper bearing, shims, and flashing. That beam added a few hundred dollars and avoided cracked brick and sagging in two winters. If your drawings show “header as per code,” you will probably get a plan review comment. Put the size, species, and point load path right on the plans.

The permit package that gets approved on the first review

Over the years I have learned that good drawings and a few specific notes save weeks. The City of London’s Building Services staff are pragmatic. They look for clarity, dimensions, and code touchpoints.

For a simple enlargement or a new opening, your drawings should show the existing wall, the proposed opening size, lintel details, and location on the elevation. Include window type for egress bedrooms. If a window well is involved, show the plan view with the 760 millimetre clearance. For doors, show the threshold and landing conditions, especially if you are converting a window to a door that now opens onto grade. A drop over two steps needs a proper landing. If you are in a heritage area, add color photos of the existing façade and a brief rationale for material choices.

If you are working through a contractor for door installation London Ontario, ask them to put their BCIN or engineer stamp on structural details if required. Some projects do not need an engineer, but I have had challenging brick veneer situations where a quick lintel review and letter eased the plan examiner’s mind.

The process, step by step

If you are new to permitting for London window and door work, this is the sequence that keeps things clean.

Confirm scope and triggers. Decide if your project touches structure, fire separations, or egress. Call Building Services if any part is gray. Assemble drawings and product data. Simple, dimensioned plans, lintel spec, window well clearance, and manufacturer cut sheets for egress and safety glazing as needed. Submit application and pay fees. The City’s online portal accepts residential applications, or you can file in person. Most small alteration permits clear in a few business days if complete. Schedule inspections. For new or enlarged openings, expect at least a framing inspection before you close, and a final inspection after installation and exterior finishes are on. Like-for-like swaps have no inspection because there was no permit. Keep labels and take photos. Leave energy and NAFS labels on until final. If a label peels off early, photos in place help.

On a recent project in Oakridge, we enlarged a basement egress window and added a walkout door to the backyard. The permit was approved in three days because the drawings called out the LVL header, showed the 760 millimetre well clearance, and included the unit’s clear opening math. The inspector checked the framing and well before we insulated. Final passed the following week.

Site logistics many people forget

Permits are not the only roadblocks. A smooth window and door replacement London job also depends on how you handle the street and the site.

If you plan to place a dumpster or materials on the road or boulevard, you need a right-of-way occupancy permit from the City. Most crews put bins on the driveway to avoid this, but tight lots in Old South or Woodfield sometimes leave no choice. Book ahead, and mind the lead time. Fines for unauthorized street occupation cost more than the permit.

Sidewalk protection and scaffolding on the boulevard also trigger permits. Neighbours call when they step into a lane closure without warning. I post clear signs and schedule deliveries outside rush hours. Noise bylaws in London typically limit construction noise to daytime hours. Early Sunday glass cuts will not make friends.

If you are excavating for a deeper window well, make an Ontario One Call locate request. Gas, hydro, and telecom lines wander across side yards more than you think. I have uncovered shallow telecom lines inches from foundation walls. A locate ticket costs nothing and saves outages and liability.

Choosing products that satisfy inspectors and daily life

Aesthetics matter, but so does the way a unit performs under London’s climate. Between lake effect snow, spring freeze-thaw, and hot July sun, product selection is not theoretical.

For replacement casements, I like triple-pane units on north and west elevations. They quiet traffic from busy streets and tame drafts. On south elevations with deep overhangs, a high Energy Rating double-pane with low-e tuned for solar gain sometimes makes better sense. Inspectors do not judge taste, but they do read labels. Keep every factory label until the last inspection. It spares you a scramble.

When clients ask for steel door installation London Ontario on the front entry, I point them to foam-filled slabs with thermal breaks at the sill and an adjustable threshold. A good sill pan under the threshold keeps meltwater out of the subfloor. It takes an extra hour to cut, level, and set a pan, and it has saved me thousands in callbacks. If your door opens onto a porch without a landing that meets width and depth rules, add that to the scope and the permit. Expect an inspector to ask about it even if the old door looked the same.

Sidelites and transoms lift a façade, yet they also raise safety glazing questions. If the sidelite is narrow and within the impact zone of the latch side, specify tempered glass. If you are replacing a door adjacent to a staircase, protect the landing with proper guards and verify swing clearances. I once had to flip the hand of a door to avoid swinging over a stair tread. Catch that on paper.

Working in condos, semis, and heritage homes

Not every job is a detached house on a wide lot. Condominiums add layers. Even if your change is inside your exclusive use area, the corporation likely controls exterior appearance and penetrations through the building envelope. You might win City approval, then wait for board sign-off. Plan for that time. In high-rises, altering a balcony door can involve fire alarm zones and pressurization rules. Bring in a contractor who has worked that arena before.

Semi-detached and row houses complicate matters at party walls. You will not be adding windows to a party wall. If you remove and replace units in the side wall near a property line, spatial separation rules and fire resistance ratings can limit window size and type. Thin lots in older neighbourhoods have tight clearances. A small change to glass area may keep you compliant while still brightening a room.

Heritage homes in Woodfield, Bishop Hellmuth, and Blackfriars have their own rhythm. I have won approvals with wood or aluminum-clad wood units that preserve sightlines and muntin profiles. Vinyl with chunky frames often struggles. The city’s heritage planners respond well to thoughtful submissions that show you care about the streetscape. Hand them photos, profiles, and color swatches, and you turn a gatekeeper into a partner.

Budgeting with permits and contingencies in mind

Clients often ask how much a permit will add. For a straightforward residential alteration permit in London, fees are modest compared to material and labor costs. Think in the low hundreds of dollars. The bigger costs come from scope creep and surprises inside the walls. Rot around sills, undersized headers, or hidden utilities close to a window well can add 10 to 20 percent to a project if you have not set a contingency.

In my quotes for london window and door projects, I carry a contingency line and spell out allowance items, such as engineered headers or tempered glass upgrades. It removes friction when the inspector asks for a tweak and helps clients feel in control. If you are comparing bids for window and doors London Ontario, look beyond the bottom number. Ask who pulls the permit, who handles inspections, and how extras are priced. A low bid that ignores code may become the expensive one.

Coordination between trades and inspectors

Window and door work crosses boundaries. On a larger retrofit, insulation contractors, bricklayers, and electricians may touch the same openings within days. A thoughtful sequence saves damage and rework.

For example, on a bungalow in Byron, we enlarged two front windows and added a full-lite side door to the driveway. We scheduled the framing inspection the morning after headers went in, then set windows and door that afternoon. The following day, the mason returned to tooth brick around the new openings. Only after that did the insulators and drywallers mobilize. The final inspection wrapped the job. When sequencing slips, you end up tearing off fresh trim to expose a header or scraping mortar off a new sill.

Inspectors are not adversaries. They are allies who want safe houses that last. A quick call before you pour a new window well drain or close a tricky jamb can save two trips and a red tag. In my experience, London inspectors appreciate calls that flag a judgment call. They would rather talk it through than argue on site.

How this ties back to your choice of installer

The rules are the rules, yet the way a contractor navigates them makes a real difference. A firm that treats permits as an afterthought tends to cut corners elsewhere. When you interview companies for door installation London Ontario or window and door replacement London, ask about recent permitted jobs in your ward, how they handle egress measurements, what they do for sill pans, and how they document lintel sizes. If the salesperson shrugs at the term NAFS label, keep looking.

I also look for signs that a company is set up for communication. Do they provide a simple drawing with dimensions when they quote? Do they keep labels on until inspections are done? Will they coordinate with heritage staff if your house demands it? The right answers do not guarantee a flawless job, but they raise the odds.

A few real examples from London projects

A North End two-storey had small 1980s sliders in the kids’ bedrooms. The parents wanted quiet and better air sealing, so we proposed triple-pane casements. The catch was egress, because the new frames slightly reduced the clear opening. We selected a series with slim profiles, verified that the smallest dimension cleared 380 millimetres, and filed no permit because the rough openings stayed the same. We installed window opening control devices for fall protection. The inspector never visited, but our photos and labels stayed in a project file in case the house sold.

In Wortley Village, a heritage home needed new front windows. Vinyl would have been cheaper, yet the district design guidelines pushed us to aluminum-clad wood with true divided lite profiles. We submitted a heritage alteration application with photos and profile drawings. Approval arrived with conditions on color and muntin pattern. No building permit was required because the openings did not change, but the heritage permit was essential. On install day, we used wood brickmoulds milled to match the originals. Passersby assumed we had restored the old windows, which is the best compliment.

On a Westmount raised ranch, the owners wanted patio access from a basement rec room. We cut a new door opening, installed a 36 inch insulated garden door, added a landing and stairs to grade, and excavated a deep well for the adjacent enlarged egress window. That job needed a permit, a framing inspection, and a final. The lintel design went to an engineer because of point loads from above. Everything cleared smoothly because the drawings were explicit and we called for inspection at the right moment. That door changed how the family used the space, and the resale photos later sold the house in a week.

Tying it all together

Replacing windows and doors is one of those projects that can be refreshingly straightforward or unexpectedly complex. The dividing line is rarely the material or the style. It is the interplay of structure, safety, and local process. If you learn the common permit triggers, respect the egress and glazing rules, and assemble a clean application when you do need permission, you avoid the stumbling blocks.

Whether you are planning a simple london window and door refresh or a more ambitious conversion that pairs a larger picture window with a new side entry, think like a builder. Measure clear openings, not just frames. Plan lintels before you order. Keep labels, photograph the steps the inspector cares about, and line up the right-of-way paperwork if your site is tight. A disciplined process does not dampen creativity. It lets it take shape without detours.

For homeowners comparing quotes for window and doors London Ontario, look for partners who speak fluently about the Ontario Building Code and the City’s expectations. The craft of a perfect miter on a casing is still the soul of the trade. Add a clear-eyed approach to permits and codes, and you get a project that looks right, functions well, and stands up to the file folder the next buyer’s lawyer will examine.

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McCallum Aluminum Ltd is a professional window and door installation company serving London, Ontario.

For door installation in London, Ontario, contact McCallum Aluminum Ltd at (519) 433-4223 or visit https://mccallumaluminum.on.ca/.

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Landmarks Near London, Ontario

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3) Covent Garden Market — In the core? Ask about window and door replacement options.

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