After construction, windows are often sprayed with paint, silicone, stucco and plaster debris. Even the tidiest construction site leaves windows needing some special care. Post construction window cleaning requires more expertise, specialized tools and greater attention to detail than usual maintenance window cleaning. The risk of scratching the glass is very high and thought needs to be taken to select the right tools to clean the glass without causing damage. Tempered glass is particularly sensitive to scratches. The composition of the glass and microscopic flaws from manufacturing means that scrapers will scratch this type of glass. Tempered glass is tedious to clean because it needs to be manually scrubbed to remove paint and debris.
Professional glass scraper
Fresh stainless steel scraper blades
'0000' steel wool, the world's finest grade of steel wool that does not scratch glass
Goof Off (tm) to remove sticker residue
3M (tm) Scratch-free scrubber pads
Acid to break down and remove dried concrete and stucco
To remove dried concrete from glass we use muriatic or hydrochloric acid to break down dried concrete. The silica in concrete chemically bonds to the silica in the glass surface making it challenging to remove. Acid is used to chemically break these bonds so that the concrete and sand particles can be rinsed away without dragging them across the glass surface. Care must be taken to ensure that this acid doesn't run onto the stucco siding or get dropped onto concrete sidewalks and cause discolouration.
Mechanical removal of concrete with a scraper will cause the particles of sand to grind into the glass and cause permanent scratches. A scraper can only be used on the glass once all abrasive particles have been rinsed from the glass surface.
We remove manufacturers stickers by first soaking them with water and detergent to soften the paper and adhesive. Our detergent contains slickening agents to help scraper blades slide smoothly across the glass. Ideally, the scraper blade should glide on a thin layer of water and not touch the glass at all. Once the sticker has softened, we carefully use a stainless steel scraper blade designed for use on glass and lift the sticker off the glass.
Window manufacturers seal windows into their frames using silicone and can sometimes get smears of silicone on the glass. Silicone is once of the mosrt difficult substances to remove from glass, but with some elbow grease it is possible. To remove silicone we first get rid of any large globs using a fresh scraper blade and then srub the entire surface of the glass in a cicular polishing motion with '0000' steel wool.
Dried paint needs to be removed with a scraper blade. The blade needs to be inspected and changed often as the glass wil eventually dull the blade and knicks in the blade could demage the glass. We recommedend 5" wide staineless steel scraper blades as they wont rust and the stainess steel is softer then carbon steel blades.
Tempered glass, like that used on patio doors, skylights and bathroom windows is more susceptible to scratching due to manufacturing impurities in the glass. Tempered glass is designed to break apart into cubes in the case of breakage and is also known as safety glass. Using a scraper on tempered glass may push these invisible particles across the glass causing gouging to occur. Even a perfect scraper blade using the correct technique will push these 'glass fines' into the glass surface and leave visible scratches.
The best way to remove paint and adhesives from tempered glass is with a 3M anti-scratch glass scrubbing pad, or '0000' steel wool and detergent solution. Scrubbing is a more labour intensive process than scraping but prevents any chance of scratched glass. The only precaution when using scrubbing pads is the inspect them regularly to ensure that sand particles haven't embedded themselves in the scrub pad or steel wool. If a scrub pad gets dirty it may need to be rinsed out or replaced.