Getting a door to swing true, seal tight, and look like it grew there starts long before you set the unit in the hole. The quiet work, the sort that never makes it into glossy before-and-after photos, happens with a tape measure, a level, and a pencil. In and around London, Ontario, where winter wind can turn a hairline gap into a draft you feel in your bones, accurate measuring and careful prep are the difference between a clean job and a callback.
I have replaced hundreds of exterior and interior doors across the city and county. Brick veneer in Old North, vinyl siding in Fox Field, poured concrete porches in Byron, and split-levels in White Oaks all teach their own lessons. The framing behind the casing can surprise you, and older homes sometimes conceal three layers of trim and a threshold that has sunk just enough to cause trouble. The method below keeps you out of most traps, and when things go sideways, it helps you diagnose quickly.
Why measuring matters more in this climate
London sits in a climate zone that mixes freeze-thaw cycles with summer humidity. Exterior doors move with those swings. A steel door can expand on a July afternoon, a wood jamb can tighten up in February, and an aluminum sill will telegraph any unevenness in the subfloor. If your rough opening is too tight, the frame binds and the door scrapes. Too loose, the shims carry everything and the foam can’t bridge cleanly, so you get air and water pathways. Installing right means building in predictable gaps, managing water with proper pans and flashing, and ensuring the hinge side is plumb so the latch lines up every time.
Homeowners often approach door installation as a one-off project, but it rarely lives alone. Many of us doing door installation London Ontario also handle window installation London Ontario, patio door installation, and full window and door replacement London packages. That overlap matters when you think about air sealing, siding tie-ins, and consistency of finishes. If you plan window replacement London Ontario in the same season, you can coordinate brickmould profiles, capping colours, and caulking joints so the home reads as one system.
Prehung vs slab, and what that means for the opening
Most exterior door projects in London Ontario use prehung units, whether steel, fiberglass, or wood. Prehung means the door comes already mounted in a frame with hinges set and, often, a preinstalled sill and weatherstripping. A slab is just the leaf of the door. Swapping a slab on an existing frame can work for interior doors when the jambs are in good shape, but it rarely delivers a tight seal on an old exterior frame. Given our winters and the price of energy, prehung wins for exterior retrofits nine times out of ten.
Steel doors London Ontario remain popular because they balance price, durability, and security. They stand up to salt spray off the road and take paint beautifully. Fiberglass insulates better and shrugs off dents. Wood looks classic but asks more of you in maintenance. Each choice leaves the same measuring fundamentals, with small differences at the sill and brickmould.
Patio door installation adds width, glass weight, and water management to the mix. Sliding patio doors commonly replace old aluminum units from the 70s and 80s. Those openings tend to be wider, sometimes sagging slightly under undersized headers. Garden doors, which are essentially double outswing units, load the hinges more and require crisper shimming on the hinge posts. Planning for these differences helps you order the right size and prep the site properly.
Know your rough opening, not just the visible casing
The number that matters for ordering a prehung door is the rough opening, the cavity framed by studs and a header before drywall and trim. Mistakes happen when you measure the old door slab or the finished casing width. Builders and siding companies London often cover a world of sins with jamb extensions, brickmould, and caulking. When you peel it back, you find the truth.
If you are replacing a door sized in imperial, the rough opening typically sits 2 inches wider and 2.5 to 3 inches taller than the nominal unit size. For example, a 36 by 80 inch door often sits in something like 38 by 82.5 inches, allowing space for the jamb, shims, and a sill pan. That rule of thumb helps, but nothing substitutes for field verification. I have seen a “standard” opening pinch down to 37.25 inches because an old plaster return and a proud stud marched into the space.
For brick veneer homes that dominate London neighborhoods, pay attention to the masonry opening as well. Brickmould covers the gap between the door frame and brick, but it only has so much reach. When an original wood frame is unusually thick, switching to a modern insulated steel door can shorten the reveal to the brick. That affects not only aesthetics but also how well you can seal the joint.
The tools and materials that keep you honest
- 25 ft tape measure, 4 ft level, and a torpedo level for sills Laser distance measurer for quick interior checks, verified by tape Framing square, pencil, and painters tape for marking Shims, low-expansion foam rated for windows and doors, and backer rod Waterproof flashing tape, sill pan or pan flashing components, and a quality exterior sealant
A five-step measuring routine that catches problems early
- Record the width at top, middle, and bottom of the existing opening, then note the smallest number. Measure the height on both sides from the finished floor or subfloor to the underside of the header, again using the smallest. Check the diagonals of the rough opening to confirm square. Differences over 1/4 inch call for correction or planning. Verify the wall depth from interior drywall face to exterior sheathing or brick plane to determine jamb and brickmould needs. Level the sill area with a torpedo level and straightedge, noting any crowns, dips, or slope toward the interior.
This five-step pass takes ten to fifteen minutes and tells you whether the opening is plumb, level, and square, whether you need a custom jamb depth, and whether you can use a standard prehung or should order a slightly undersized unit with wider brickmould to cover irregularities.
Reading the surrounding finishes
Doors rarely live in isolation. If you are coordinating with london windows and doors changes, think about how trims and colours meet. Aluminum capping on nearby windows sets a visual standard. If your new door’s brickmould differs by even 3/8 inch in profile, the mismatch catches the eye from the curb. Suppliers serving London Ontario windows and doors typically stock matching brickmoulds and sill nosings; ask to see profiles before you order.
Siding matters, too. Vinyl J-channels and foam backers around the opening can hide framing edges and steal 1/2 inch you thought you had. When you remove an old storm door, you sometimes find the primary door set deeper than modern brickmould expects. Siding companies London often build out trim packages to correct this, but when you are installing just one door, you may need jamb extensions or custom brickmould to hit the same plane as the adjacent siding.
Inside, flooring thickness changes can bite you. If you plan a kitchen reno with new tile or LVP that raises the floor 3/8 to 1/2 inch, order a sill and sweep combination that allows adjustment. I once replaced a steel door in a Westmount bungalow, perfect reveal all around, only to have a flooring crew install click vinyl a week later. The sweep dragged just enough to annoy the homeowner. A simple sill tweak solved it, but better to account for future floor height up front.
Structural sanity checks before you touch a saw
Rough openings for doors rely on a header to carry loads above. On exterior walls with brick veneer, the lintel in the brick handles the masonry, but the wood header behind carries the roof or floor above. In many 1960s and 70s London homes, 2x8 or 2x10 headers span typical single doors. For patio doors, older builders sometimes used built-up 2x8s where a 2x10 should have been. Look for sag above the opening, cupped floors, or doors that rubbed historically. If you see diagonal cracking in nearby drywall or brick mortar joints cooking off at the top corners, pause. You may need to shore or reframe before proceeding.
Interior walls masquerading as non-load-bearing can surprise you when they carry point loads from above. If you are widening an opening, confirm load paths. When I expand a single door to a 5 ft garden door, I mark out proposed jack and king studs, then open a small inspection bay above the current header to verify what it actually bears. A half hour spent here saves you from cracked tiles and sticky doors later.
Removing the old door without damaging what you need
For most retrofit work, cut the paint and caulking lines around casing and brickmould with a sharp knife. Inside, pry gently and save the casing if it is to be reused. Pop hinge pins and remove the slab, then pull interior jamb screws and pry the frame out. If the sill is sealed to a concrete step or wood porch, expect resistance. Score the sealant, and if needed, cut the old sill with a recip saw to remove in sections.
Be methodical. Protect adjacent finishes with cardboard. If you hit hidden fasteners in masonry, back off and locate them rather than leveraging against brick corners. That is where chips happen. I keep a magnet on hand to trace screw lines through paint and caulk.
Prepping the rough opening for the new unit
Once the old frame is out, vacuum the cavity and inspect. You will often find shims left in place, splinters of old jambs, and clumps of brittle insulation. Clean until you can see bare framing and subfloor or threshold substrate. Look for water staining at the sill area. If you see darkened wood or crumbling particleboard, dig deeper. I once chased a small stain at a North London entry that led to a leaking exterior light above the door. Had we ignored it, new flashing would have been compromised by water entering from above.
Correct any rot. Sister compromised studs and replace soft subfloor. For concrete porches that slope toward the house, consider a low, tapered sill plate with a waterproof membrane beneath to maintain a slight outward pitch under the door sill. A level sill is key for outswing garden doors, while sliders can tolerate slight slope as long as the track remains level left to right.
Dry fit the new unit, if you have it on site. Confirm clearance, mark hinge side shimming points on the studs, and predrill for long screws at hinge locations. Remove the unit and proceed to flashing.
Sill pans, flashing, and air sealing that works in London weather
Modern best practice uses a sill pan or pan flashing under every exterior door. This creates a backstop for any water that gets by the threshold, directing it to the exterior. Preformed pans are available, but well-executed site-built pans with corner patches of self-adhered flashing perform just as well. The sequence matters. Flash the sill so that any water runs out, not into the wall. Lap flashing tapes shingle-style, lower to upper. At the jambs, bring flashing a few inches up from the sill, and integrate with existing housewrap if you have it exposed.
I prefer to foam after the unit is fastened and squared, using low-expansion foam rated for windows and doors. That matters. The high-expansion stuff you find in the plumbing aisle can bow a jamb enough to ruin your reveal. Backer rod and high-quality sealant on the exterior joint finish the air and weather seal. In winter, make sure the sealant can cure at ambient temperature or use a cold-weather rated product.
Setting the door, step by step in narrative form
Place the door into the opening from the exterior, resting the sill on your pan. Center it loosely, then step inside. Use your 4 ft level on the hinge side jamb. This side is your reference. Shim at hinge points first, snug but not so tight you bow the jamb. Drive a long screw through the hinge holes into the stud. I use two per hinge on heavy slabs, one on lighter units initially, adding the second after I confirm swing.
Check the head for level and adjust with shims at the lock side as needed. Close the door gently and look at the reveal around the slab. It should be even, roughly 1/8 inch on most units. If the head is tight on the latch side, lift that side slightly or relax the hinge side shim at the top. Patience here saves you from later latch issues. When satisfied, add fasteners at manufacturer-recommended points, often hidden behind weatherstripping.
Foam the cavity lightly, starting at the bottom and working up. Resist the urge to fill in one pass. Let it set, then top up as needed. Too much foam and the jamb bows inward. On the exterior, install brickmould if it is separate, then seal the perimeter with a high-quality caulk, tooling the bead smooth. On brick, a backer rod behind the joint helps you hit the right shape and depth for long-term performance.
Interior casing goes back on after foam cures and is trimmed. If you use new casing, nail into solid backing, not just drywall, and keep your miters tight. A bead of paintable caulk at the wall joint creates a clean line.
Special notes for steel door installation London Ontario
Steel doors often come with composite bottom rails and sills that resist rot. That is good news in our wet seasons. They also carry factory paint or primer that benefits from a topcoat after installation. In winter, avoid painting if temperatures drop below the paint manufacturer’s recommended range. Hardware sets on steel doors need accurate drilling and backset alignment to avoid dimpling the skin. Use a sharp hole saw, a pilot bit, and support the skin from behind if you can.
Security screws through hinges into framing are a wise addition. London sees its share of attempted prying at back entries. Reinforcing the strike side with a metal plate behind the jamb adds strength without changing the look.
Patio door realities on older homes
Sliding patio doors weigh more than most expect. A retrofit slider can tip the scale at 180 to 260 pounds, more for triple-glazed units. Plan manpower and safe handling. Old aluminum tracks often sit in a mud bed over concrete or a built-up wood sill. When you remove them, you uncover rough concrete or out-of-level framing. Spend time truing the base. A straight, level track prevents racking and unlocks smooth operation.
Water management on patio doors matters even more. The threshold sees splashback and snow buildup. Sill pans and generous flashing are your friends. For garden doors, mind the outswing clearance over decks and pavers. I have had to notch a new deck board more than once because a sweep brushed it. Better to anticipate and trim the board before install day.
Integrating with adjacent windows and siding
Many homeowners stagger projects, tackling window replacement London in spring and an entry door in fall. That can work if you plan the interfaces. Jamb depth and brickmould profiles should match across the facade. If you have london ontario windows replaced with a specific capping colour, get the exact code for your door trim. It is tempting to eyeball “Sandstone” from a chart, only to find it skews warmer than the windows from a different supplier.
If you are doing window and doors London Ontario together, sequence matters. I prefer to install the door after the adjacent windows so I can tune the brickmould and capping to a continuous line. Siding returns into the door trim also look cleaner if the door goes in last, but that depends on the crew and the product. Good siding companies London will coordinate the order with you to reduce rework.
The Ontario Building Code and practical clearances
While the Ontario Building Code is dense, a few practical notes apply to door installs. Exterior steps need consistent riser heights after a new threshold goes in. If your new sill sits 1/2 inch higher, your top riser increases, and the stair can become noncompliant and, more importantly, feel off underfoot. Plan to adjust the first step or add a thin overlay to keep risers within tolerance.
Egress dimensions apply to some doors, particularly secondary exits in renovations. Measure clear opening with hardware in place if you are pushing limits on tight spaces. For accessibility, low-profile sills paired with beveled transitions make a big difference. Discuss those needs up front during window and door replacement London consultations so the ordered unit meets your goals.
Common pitfalls and field fixes
A frequent misstep is trusting the floor to be level. London’s older homes settle. If you do not check and correct the sill plane, you chase the reveal for half an hour and still land with a rub at the head. A composite or PVC sill shim works well here, and it won’t compress like cedar shims under long-term load.
Another issue is ordering a door with the wrong swing. Think from the outside looking in when you define left or right hand inswing or outswing. I have walked homeowners through a doorway with a rectangle of painters tape marking the swing arc. People visualize better that way. It takes a minute and avoids weeks of delay.
Finally, beware of over-foaming in cold weather. Foam cures slower in January. Installers get cold and tend to lay it on thick, hoping it fills gaps in one pass. It expands later, bows the jamb, and you get a latch that misses by a hair. Warm the cans in a bucket of lukewarm water, apply in lifts, and you keep control.
When to call a pro, and what to expect from one
If you open a wall and find a sagging header, water stains you cannot trace, or a concrete step bonded to an old sill with a mystery mastic, bring in help. Crews that focus on london windows and doors do this weekly. A seasoned installer will walk you through rough opening adjustments, recommend sill pan options, and tie in with your future plans for window replacement London or siding work.
A https://finnbqjy917.yousher.com/door-installation-london-ontario-measuring-and-preparing-openings good pro measures twice, explains the numbers, and shows you how the new unit will sit relative to floors and finishes. They should talk about shimming strategy, fastener placement, and air sealing. If they are doing steel door installation London Ontario, ask where they plan to add long screws and how they will reinforce the strike. For patio door installation, ask how they will manage the threshold and what warranty applies to water intrusion.
Pricing varies with complexity. A straightforward prehung steel door swap with standard brickmould, clean opening, and no structural issues sits in one tier. Add rot repair, custom jamb depth, or a sagging header, and the number climbs. Transparency helps. I show clients photos of the opened framing and explain the options, from minimal fixes to best-practice rebuilds.
Ordering smart to fit the opening you have
Once you have your smallest width and height, wall depth, and sill conditions, you can order with confidence. In many London Ontario windows and doors showrooms, standard sizes are in stock in common colours. If you need custom jamb depth to suit thick plaster walls or a foam-backed siding detail, expect a lead time of a few weeks. Match hardware prep to your lockset. Multi-point locks on taller slabs are worth the upgrade in windy exposures, and they need correct prep from the factory.
Consider energy performance. A foam-filled steel slab paired with a thermally broken sill and good weatherstripping will feel warmer underhand and underfoot. For south-facing entries, a fiberglass slab with a light colour finish resists heat cycling better than a dark steel door. These are small choices that add up in day-to-day comfort.
Tying the project into broader exterior upgrades
If you are mapping a year of exterior improvements, stack your work in a logical sequence. Roof and eaves first if they are due, so water management is sound. Window installation London Ontario next, then door installation London Ontario, then siding. That order keeps your weather barriers continuous and reduces recapping or re-caulking. If budget forces a different order, communicate clearly among trades. A door installed just before new siding should receive temporary protection at the trims and a plan for final caulking after the siding crew completes their work.
A brief anecdote from the field
We replaced a front entry in a Masonville two-story where the homeowner complained of a whistling sound on winter nights. My initial measurements showed a standard 36 by 80 prehung would fit, but the diagonals were out by 3/8 inch and the sill dipped 1/4 inch to the interior on the latch side. The old frame masked it with thick caulk. We rebuilt the sill with a tapered composite shim, flashed a site-built pan, and set a foam-filled steel door with a multi-point lock. The reveal came in clean, the latch lined up on the first try, and the whistle vanished. In February, the same client called about window replacement London for the living room. Because we had documented jamb depth and brickmould profiles on the door, we matched the new london window and door package so the facade lines stayed consistent. Sometimes one careful door install opens the door to a coordinated, energy-smart refresh.
Final checks that signal a job done right
Before you call it finished, run your hand around the interior on a windy day or with a fan pressurizing the entry slightly. Feel for air leaks. Operate the latch and deadbolt several times. Make sure the sweep meets the sill evenly without dragging. Look at the exterior caulk line for continuity. Confirm the threshold screws are snug but not over-tightened, to avoid warping the sill. Step back from the curb and check that the brickmould and capping align with nearby windows. Small adjustments here make the difference between a passable job and one that looks intentionally crafted.
Door installation in London Ontario, done with care, protects your home from the elements, saves on heating, and upgrades the daily experience of leaving and returning. The measuring and preparation you do on the front end pay you back every time the latch clicks, the weather stays out, and the door swings free. And if you are pairing this with broader work from window and doors London Ontario providers, the same discipline applies: measure what is real, plan for water and air, and build in room for materials to move with the seasons.
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Name: McCallum Aluminum LtdAddress: 3392 Wonderland Rd S, London, ON N6L 1A8, Canada
Phone: (519) 433-4223
Website: https://mccallumaluminum.on.ca/
Email: [email protected]
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https://mccallumaluminum.on.ca/
McCallum Aluminum Ltd is a reliable window and door installation company serving London, Ontario.
For door replacement in London ON, contact McCallum Aluminum Ltd at (519) 433-4223 or visit https://mccallumaluminum.on.ca/.
McCallum Aluminum Ltd provides expert exterior renovation help for exterior doors, helping homeowners improve curb appeal across nearby communities.
To find McCallum Aluminum Ltd on Google Maps, use: https://www.google.com/maps?cid=10246687099425416717.
Looking for a trusted installer near you? Call (519) 433-4223 and learn more at https://mccallumaluminum.on.ca/.
Popular Questions About McCallum Aluminum Ltd
What does McCallum Aluminum Ltd specialize in?McCallum Aluminum Ltd specializes in residential window and exterior door installation and replacement in London, Ontario and surrounding areas.
Where is McCallum Aluminum Ltd located?
3392 Wonderland Rd S, London, ON N6L 1A8, Canada. Google Maps: https://www.google.com/maps?cid=10246687099425416717
What areas do you serve?
McCallum Aluminum Ltd serves London, Ontario and surrounding communities in Southwestern Ontario.
What are the business hours?
Monday–Friday: 8:00 AM – 4:00 PM. Saturday–Sunday: Closed.
How do I request a quote or estimate?
Call +1 (519) 433-4223 or visit https://mccallumaluminum.on.ca/ and use the contact form.
Do you install patio doors and entry doors?
Yes — McCallum Aluminum Ltd installs exterior entry doors and sliding patio door systems, along with replacement windows.
How can I contact McCallum Aluminum Ltd?
Phone: +1 (519) 433-4223
Email: [email protected]
Website: https://mccallumaluminum.on.ca/
Google Maps: https://www.google.com/maps?cid=10246687099425416717
Facebook: https://www.facebook.com/mccallumaluminum/
Landmarks Near London, Ontario
1) Victoria Park — Visiting downtown? Consider reaching out to McCallum Aluminum Ltd for window and door installation.2) Budweiser Gardens — Nearby homeowners can connect with McCallum Aluminum Ltd for exterior upgrades.
3) Covent Garden Market — In the core? Ask about window and door replacement options.
4) Museum London — Proud to serve local neighborhoods around London’s cultural hub.
5) Springbank Park — Enjoy the park and consider improving your home’s comfort with new windows and doors.
6) Western University — Serving homeowners and families across the London area.
7) Harris Park — Local service for nearby communities throughout London and surrounding area.
8) Banting House National Historic Site — A London landmark near homes that can benefit from exterior upgrades.
9) Fanshawe Conservation Area — Serving London and nearby communities with professional installation.
10) Masonville Place — In North London? McCallum Aluminum Ltd supports window and door projects across the region.