Window and Door Installation Guides

Windows

Three install methods, every one of them code-aware and water-managed: Nail-Fin (new construction / full-frame), Retrofit (pocket / insert), and Block-Frame (straight-through). Pick the method that matches your wall.

Tools required

Verify the unit + the opening

Most failed installs start before a single screw goes in. Check what shipped, then check what you're putting it into.

Do NOT proceed with damage — even a small chipped corner on a vinyl frame compromises the air seal. Photograph, log a claim within 48 hours, and stop.

Pull siding + remove the old unit (replacement only)

For new construction, skip to Step 3. For full-frame replacement, the goal is exposed sheathing + WRB around the entire opening so you can re-flash from scratch.

If your home was built before 1978 in the US (or before 1980 in Canada), exterior paint may contain lead. Wet the surface before scraping and use proper PPE.

Flash the rough opening (sill pan first)

Water is the #1 reason windows fail. A sloped sill pan + shingled jamb flashing turns the opening into a drainage path even if the sealant fails 10 years from now.

Don't reverse the flashing order. Sill first, jambs next (over sill), head last (over the nail fin). Lapping the wrong way funnels water INTO the wall.

Bead the nail fin + dry-set the window

The window is set from the exterior side, with a continuous bead of sealant on the BACK of the nail fin so it self-seals to the WRB as you fasten.

Shim, plumb, square, then fasten

Get it level, plumb, and square BEFORE you finish nailing. Two fastening systems work together: the nail fin holds plane against the WRB; jamb screws hold the unit square. Per SAWDAC industry spec, BOTH are required — the fin alone is not enough.

Overdriving fasteners deforms the jamb. Drive until snug, no more. If a fastener spins or strips, back it out, plug the hole with epoxy, and re-drill.

Head flashing + re-integrate the WRB

Now that the unit is fastened in plane, the head gets its drip cap and flashing tape — the last layer of shingled water management. Per building code, a drip cap is REQUIRED above every window head.

If the head flashing isn't installed AFTER the window, you've created a water channel into the wall. There is no other order that works long-term.

Two-bead foam insulation + air-barrier continuity

The shim cavity is now a thermal bridge unless you fill it. SAWDAC spec: TWO beads of low-expansion polyurethane foam on all four sides — one near the exterior, one near the interior — so the foam makes continuous contact with the interior poly air/vapour barrier.

Restore siding + interior trim + water test

Final water seal on the exterior, casing on the interior, and the operation tests that prove the install.

Entry Doors

Pre-hung fiberglass or steel entry door install — inswing, single or double, with or without sidelites. Eight steps cover everything from rough-opening inspection to the final water test.

Tools required

Pre-installation inspection

30 minutes of inspection up front saves hours later. Check what shipped, then check what you're putting it into.

If your existing threshold is rotted on a replacement, the rot is almost always worse in the framing behind it. Don't paper over — pull the trim and inspect the sheathing.

Remove the existing door (replacement only)

New construction: skip to Step 3. For retrofit, the goal is a clean, square, ready-to-flash rough opening.

Flash the opening + prep the sill

Water management is the #1 cause of premature door frame rot. Done right, the rough opening sheds water even if the sealant fails decades later.

Don't skip the sill pan. The threshold's gasket is the FIRST line of defense; the sill pan is the LAST line when (not if) that gasket fails.

Set the pre-hung unit + tack it

The unit goes into the opening from outside, gets centered, and is temporarily fastened so you can adjust before committing.

Plumb, square, shim, and final-fasten

This is the make-or-break step. A door that's plumb and square will swing perfectly for decades. One that's racked will rub, stick, and refuse to latch.

Driving fasteners between shims (not through them) bows the jamb inward and the door will bind. Always shim BEHIND every fastener.

Install hardware + verify operation

Lockset, deadbolt, handle — and the strike plate is where most installs need final dialing.

Insulate, weather-seal, and finish-flash

Fill the shim cavity (correctly), apply the exterior weather seal, and put the head flashing on AFTER the unit is fastened.

Leaving the bottom exterior bead OPEN is correct. The threshold and frame have internal weep paths — sealing the bottom traps any water that gets in and rots the sill from inside.

Operation test + finishing + warranty

The install is mechanically done. These last checks prove it works and lock in your warranty coverage.

Sliding Patio Doors

Install a 2-, 3-, or 4-panel sliding patio door. Heavier glass, longer track, larger opening — but the same fundamentals: square frame, level track, drained sill. Eight steps, two people minimum.

Tools required

Inventory + opening verification

Sliding doors arrive in multiple pieces — frame, fixed panel(s), operating panel(s), screen, hardware. Inventory everything before you start.

Store glass panels VERTICALLY against a wall, padded at the contact points. Laying them flat or stacking is how 80% of pre-install panel breaks happen.

Remove the existing door (replacement only)

New construction: skip to Step 3. For retrofit, remove panels first, then the frame.

Flash the opening (oversized sill pan)

A slider's threshold spans 5+ feet of opening. Any water that gets in has 5+ feet of sill to find. The sill pan is non-negotiable.

Sliders cannot tolerate a sill that holds water. If your existing porch slopes back TOWARD the house, you need to address that BEFORE installing — either grind a slope or build the door up on a properly sloped subsill.

Set + square the empty frame

Install the frame alone, no panels yet. With less weight and no panels to fight, you can square it perfectly.

Install the fixed panel(s)

Fixed panels mount permanently into the frame and provide the alignment reference for the operating panel(s).

Install the operating panel + adjust rollers

This is the most physical step. Get it right and the panel glides for decades.

If the panel drifts on its own when you let go in the middle of the track, the frame is NOT level. Don't try to fix this with roller adjustment — re-check the threshold and re-shim the sill if needed. Roller adjustment can't fix a tilted track.

Insulate, head flash, exterior seal

Same water-management sequence as a door — low-expansion foam in the cavity, drip cap and head flashing AFTER the frame is set, exterior bead with bottom kept open.

Operation, weatherstrip, finish + warranty

Final adjustments, casing, water test, warranty registration.

Measure before ordering