Window Installation Inspection Checklist: What to Check Before You Sign Off

When the crew says the job is done, do not take their word for it and do not take ours. Walk it yourself. A window that sticks, a missed bead of sealant, or a scratched pane takes minutes to fix while the installers are still on site.

This checklist goes window by window, then covers the paperwork. Print it or pull it up on your phone. It is part of our California window guide.

Before you start

• Do the walk-through in daylight, with the crew lead.
• Have your contract and the order schedule in hand, so you can check each window against what was ordered.
• Carry a notepad or use your phone, and photograph anything you want fixed.
• Check every window, not a sample. Problems are rarely evenly distributed.

Part 1: each window, from inside

Is it the right window?

• Type and handing. The window opens the way you ordered, and the operable side is the side you chose.
• Glass. Obscure glass is where it should be. Grids match the pattern ordered.
• Color and hardware finish match the order, inside and out.
• The label matches the quote. Read the U-factor and SHGC on the NFRC sticker and compare them with the figures in your contract. Our guide to reading an NFRC label shows where each number is.

Operation

• Open and close every operable sash through its full travel. It should move smoothly, without scraping or binding at any point.
• A hung window should stay where you leave it, not drift down.
• A slider should roll without rocking and should not lift out of its track when pulled.
• A casement or awning should crank evenly and pull tight against the weatherstrip when closed.
• Tilt-in sashes should tilt and re-latch on both sides.

Milgard's instructions describe the standard: windows must be installed level, plumb, square, and weather-tight in the opening. Smooth operation is how you test the first three.

Locks and latches

• Every lock engages fully without you pushing, pulling, or lifting the sash to line it up.
• On windows with two locks, both engage.
• With the window locked, push on the sash. It should not rattle.
• Any vent stops or night latches work.

A lock that needs help to engage is the most reliable sign of a frame that is slightly out of square or bowed.

Reveals, gaps, and shimming

• Reveals are even. The gap between sash and frame is the same width along its length on all sides.
• Sightlines line up. On a slider or hung window, the meeting rails are parallel and meet evenly.
• The frame is straight. Sight down each jamb and along the head and sill. A frame that bows inward was squeezed by over-tightened screws or by expanding foam. Milgard warns that foam must be the low-expansion type and that frame distortion from foam is not treated as a warranty issue.
• Adjacent windows align. Windows side by side on one wall should have heads and sills at the same height.

You will not see the shims once the trim is on. What you can see is their effect: a frame that is straight and a sash that fits evenly was shimmed properly.

Glass

• No cracks, chips, or scratches. Look at each pane from an angle, inside and out.
• No moisture, haze, or debris between the panes.
• No sealant or paint smeared on the glass. Do not scrape it off yourself with a blade. Manufacturers warn that razor blades can permanently damage glass.
• Tempered glass is marked. Where safety glazing was required, look for the small permanent mark in a corner of the pane. CRC Section R324.1 (formerly R308.1) requires safety glazing in hazardous locations to carry a manufacturer's designation that is visible in the final installation. Where it is required is covered in California tempered glass requirements.

Interior seal and trim

• There is no visible daylight and no draft around the frame. On a breezy day, hold the back of your hand near the perimeter.
• The interior sealant bead is continuous and neat, with no gaps at the corners.
• Any new casing, stool, or stops are tight, with clean miters, filled nail holes, and no splits.
• Drywall returns, plaster, tile, or paint disturbed by the work have been repaired to the standard your contract describes.

Screens

• Every operable window that should have a screen has one.
• Screens sit flat in their tracks, with no bent frames, tears, or loose spline.
• Screens come out and go back in without a fight.

More on screens is on our window screen replacement page.

Part 2: each window, from outside

Exterior sealant

• The bead around the frame or flange is continuous at the head and down both sides, with no gaps, bubbles, or pulled-away sections.
• The bead is tooled, meaning pressed into the joint and smoothed, not just laid on the surface.
• Sealant is on the joint, not smeared across the stucco, siding, or frame.
• The color is what you agreed.

Weep holes and the sill

This is the item most often done wrong and least often checked.

• The window's weep holes are open. Find the small slots on the exterior face of the bottom of the frame. They should not be covered by sealant, trim, or stucco. JELD-WEN's instructions state: do not seal weep holes or channels.
• On a flush-fin retrofit, the bottom sealant has gaps. AAMA 2410 calls for the sealant along the sill to be left open for at least an inch in line with the old frame's weep holes, or near each corner if there are none, so trapped water can escape. A bottom edge sealed solid from corner to corner is not correct.
• The sill is supported. The bottom of the frame should not flex when you press on it.

Why this matters is explained on our window flashing and waterproofing page.

Flange, trim, and cladding

• On a retrofit, the flush fin sits flat against the wall all the way around and fully covers the old frame.
• The head flashing or drip cap above the window, if there is one, is not covered or blocked by the new flange or sealant.
• New exterior trim is tight, caulked, and primed or painted as agreed.
• Stucco or siding around the opening is not cracked or chipped by the work. If stucco was patched, the patch is complete to the stage your contract specifies, and you know when the remaining coats and paint will happen.

Frame condition

• No scratches, dents, or cracked corner welds on the frame.
• Protective film is removed from frames, as the manufacturer directs.

Part 3: code items worth a second look

The building inspector checks these on a permitted job. You can check them too.

• Bedroom windows still open wide enough. A replacement window in a sleeping room has to remain usable as an emergency escape opening. The code's allowance for replacement windows is in CRC Section R319.5 (formerly under R310). If a bedroom window now opens noticeably less than the old one did, ask how it complies. See egress window rules.
• Low upper-floor windows. CRC Section R321.2.1 covers operable windows whose opening is less than 24 inches above the floor and more than 72 inches above the ground outside. If you have one, confirm that the limiter or opening control device that was specified is installed and works. See window fall prevention.
• Tempered glass where required, as above.
• Smoke and carbon monoxide alarms. CRC Section R310.2.2 ties permitted alterations to smoke alarms located as required for new dwellings. Inspectors commonly check alarms at a window final, so make sure yours are in place and working before the inspection.

Part 4: the site

• Old windows, glass, and packaging are gone.
• Floors are vacuumed, sills wiped, and tracks free of debris and screws.
• Outside, the ground under each window has been checked for glass, nails, and screws. Walk it yourself, especially lawn and play areas.
• Plants, hardscape, and exterior fixtures are undamaged.
• Furniture and anything the crew moved is back where it was, if that was the agreement.
• Window coverings and alarm sensors are reinstalled if that was in scope.

Part 5: the permit final

If the job had a permit, it is not finished until the building department signs it off. Whether your job needed one is covered on our permits for retrofit windows page.

• Ask when the final inspection is scheduled and whether you need to be home.
• Leave every NFRC label on the glass until the inspector has been.
• Get proof of the final: the signed permit card, or the record from the city or county's online permit portal.
• Do not treat the job as closed, or the last payment as due, on a permitted job that has not passed its final unless your contract says otherwise.

A finaled permit matters later. It is the record that the work was legal, and buyers and their inspectors ask for it.

Documents to keep

Keep paper copies in one folder and scans in the cloud. If you sell the house, the next owner will want the warranty and the permit record.

What to do with your punch list

1. Write every item down, with the window's location and a photo.
2. Give the list to the crew lead before they leave. Most items are adjusted on the spot.
3. For anything that needs a part or a return visit, get a date.
4. Hold the final payment until the list is complete, as your contract provides. Payment terms are covered on our California window contract requirements page.
5. Note the completion date and keep it with your warranty documents.

After that, a little upkeep keeps the windows working as installed. See our window maintenance guide.

Sources

• California Energy Commission, 2025 Building Energy Efficiency Standards, Section 110.6(a)5 (labeling) and Section 10-111 (temporary and permanent labels)
• California Energy Commission, 2025 Single-Family Residential Compliance Manual, Chapter 2 (certificate of installation, CF2R)
• 2025 California Residential Code, Sections R310.2.2, R319.5, R321.2 and R324.1
• FGIA, AAMA 2410-13, Sections 6.4.4 to 6.4.11 (licensed copy published by Anlin)
• Milgard, Installation Information and Frequently Asked Questions
• JELD-WEN, Installation Instructions for Vinyl Windows with Integral Flush Fin (JII-90024), retailer-hosted copy
• Milgard, What to Expect

Working with Heritage Exteriors

Walk the job with us before final payment; we would rather you find something on that walk than a month later. Bring this list; we will go through it window by window. Licensed in California, CSLB #1055919. Call (916) 546-2991.