The International Window Cleaning Association, or IWCA,  has dedicated itself to educating the construction industry about the hazards of post-construction window cleaning for decades. While it can be a profitable sub-segment of the window cleaning industry, there are several keys points that an experienced window cleaner needs to know before attempting post-construction window cleaning. 

1. Discuss pre-existing glass damage with the builder early in the build. 

Having a good relationship with a builder and being able to talk to them about pre-existing conditions is important. Proper storage and protection of all windows on the job site is key to them not being damaged during construction. This includes keeping windows out of the way of other trades before installation and keeping the protective, blue plastic wrap on the glass during construction. 

2. Use a 'Cleaner to Builder' liability waiver.

Window cleaners may have standard liability waivers that they use for residential, commercial, and route window cleaning, but post-construction window cleaning should always be an additional waiver. The IWCA has a sample copy that they recommend using on their website. It specifically spells out that window cleaners need to remove construction debris that has adhered to the window during the construction process. Removing that debris is necessary, but doing so may damage the glass beneath. 

3. Walk through and document damage before starting your project.

When it is time to do the post-construction window cleaning, be sure to do a walk through with the builder or the general contractor first. Point out any damage that you can see with the naked eye -- deep scratches, metal shavings embedded in the glass, globs of cement, and even weld slag, or debris from welding. Reiterate to the builder that damage can and will occur as you attempt to remove all the construction debris from the window glass. 

4. Change razor blades frequently throughout the project.

Another tip for successful post-construction window cleaning is to use a fresh razor blade in your scraper, preferably a new one for every window pane. While that does mean using many razor blades for a custom home, it is important to your success. As you remove construction debris, it nicks the razor blade and minuscule pieces get lodged in the metal itself. Your next pass with your scarper could scratch the glass. Changing your blade often will prevent this from occurring. 

Post-construction window cleaning is a serious business that requires educating the builder and partnering with them for a successful outcome. If your considering doing your own cleanup, consider talking to a post-construction cleaning crew for tips.