Window cleaning after construction: stickers, overspray and scratch risk

New windows arrive at a jobsite perfect and leave the construction phase covered in stickers, overspray, stucco, silicone and fingerprints. Cleaning them is the most visible part of a final clean and the one with the highest risk of expensive damage. Here is how we do it and why.

The razor blade problem

Ask any window cleaner and they will tell you a razor blade is the fastest way to get paint and adhesive off glass. They are right. It is also the fastest way to scratch tempered glass, and most of the glass in a new home is tempered: doors, sidelights, windows near floors and tubs, anything large.

Tempered glass can carry tiny fused particles on its surface from the tempering process, called fabricating debris. A metal blade catches those particles and drags them, leaving fine scratches that show in low sun. The glass manufacturer’s warranty will not cover it, and neither will ours.

So our rule is simple: no metal blades on tempered glass, and we assume glass is tempered until the label proves otherwise. We use plastic razors, solvents appropriate to the residue, and time.

Stickers and labels

Manufacturer labels protect the glass and, importantly, they carry the information the builder may need for warranty. We photograph every label before it comes off.

To remove them: a corner lifted with a plastic blade, a slow peel at a low angle, then warm water and a mild solvent for the adhesive. Labels that have baked on through a summer come off in pieces and take patience. Rushing them is how blades get used.

The scratch under the sticker. This is the one we check for on every window. Glass gets scratched during handling and installation, and the sticker hides it. When the sticker comes off at final clean, the scratch appears, and if nobody is looking, the homeowner finds it a week after closing and assumes we did it. So every pane gets looked at in raking light the moment the label is off, and any scratch goes on the flag sheet with a photo, before we clean the rest of the window.

Overspray

Paint overspray on glass comes off with a plastic razor and a lubricant, pane by pane. Oil-based overspray takes a solvent. Overspray on frames and hardware is a different problem: it usually cannot be removed without damaging the frame finish, so it is flagged for the painter.

Stucco, mortar and concrete splatter

Masonry splatter is alkaline and bonds to glass. If it is fresh, it comes off with water and a plastic scraper. If it has cured, it takes a specialized cleaner and more time, and if it has been on the glass for months it may have etched. That goes on the flag sheet. The mason’s protection should have prevented it, and the builder will want to know.

Silicone smears

Caulking around windows leaves silicone fingerprints and smears on the glass. Silicone does not dissolve in water. We use a silicone-specific remover on a cloth, never poured on the frame, and a plastic blade.

Tracks, screens and frames

The parts people forget. Window tracks are full of drywall mud, sawdust and dead flies. We vacuum, scrub and wipe them dry. Screens come out, get washed, dried and reinstalled. Frames get wiped with a cleaner safe for the frame material, which is not the same product as the glass cleaner.

The second story

Interior glass is always included. Exterior second-story glass is included wherever there is safe access from the ground, a deck or a roof with a walkable pitch. Where it needs a lift or a ladder on uneven ground, we say so in the quote rather than skipping it quietly.

What the homeowner should know

Low-E glass has a microscopically thin metallic coating, almost always on an inside surface of the sealed unit where you cannot touch it. But some specialty glass carries a surface coating. If the window label mentions a surface coating, the care instructions matter: no ammonia, no abrasive, soft cloth only. We leave those instructions with the builder when we see them.