When it comes to construction window cleaning, it is important to realize it is a very specialized form of window cleaning.
There are substantial challenges in removing construction debris from glass without scratching, and it is therefore not something that should ever be attempted by anyone not specifically skilled in this area. This section illustrates some of these challenges and discusses the major topics involved in this area.
In theory, windows in a construction environment would be covered at all times, protecting them from paint, plaster, and other construction debris. Unfortunately, in practice this is rarely the case, where the protection is usually incomplete, damaged, or nonexistent. Given this reality, choosing a skilled construction window cleaner is vital. The following photos show the conditions one could expect to find in a construction environment.
There are many commonly held ideas about what is, and what is not, safe to use to clean windows. Unfortunately, many of these ideas are not valid. Below is a list of the most commonly spread falsehoods about glass scratches.
If used properly, a scraper will not scratch glass. This includes any size or style of metal scraper.
This is also incorrect. Aside from leaving sections of the glass inadequately cleaned, and nick in the scraper with not adversely affect the glass.
This is also false. Experimentation has shown repeatedly that #0000 steel wool with not scratch the glass surface.
With some of the myths exposed, what are some facts about construction window cleaning? Construction window cleaning carries a very high risk of glass damage if excess construction debris is present or if the window cleaner is not properly trained. Here is a list of what can cause scratches.
- Construction debris.
- Construction debris behind a scraper, or rust on a scraper.
- Construction debris or rust in steel wool.
- Construction debris in a strip washer.
- Fabricating debris fused to the surface of low-quality tempered glass during the tempering process.
Proper Training and Techniques
Given the magnitude of the challenges faced in construction window cleaning it is clear that proper training and techniques are vital to minimizing the amount and severity of glass scratches. Listed below are some basics of construction window cleaning that, when followed, can greatly reduce scratches. For a more detailed discussion of this topic, refer to the article titled Constuction Window Cleaning Basics.
- Always keep the glass wet when scraping construction debris from the glass.
- Use only new razor blades or sharpened scrapers.
- Never move the scraper backwards on the glass. Construction debris caught behind the scraper can scratch the glass.
- Notify the project manager at the first sign of excessive construction debris on the glass. The offending party should be held responsible for any extra cost or liability for removing the construction debris.
- Get scratched glass waiver signed for all tempered glass prior to starting any window cleaning. For example, "(Your company name) will not be liable for any scratches on any tempered glass".
Know Your Glass
In order to be able to properly clean windows in a construction environment, or to be able to manage those who do, one must know the basics about the glass fabrication process. For example, one should know the difference between tempered and annealed glass. Just as important is the ability to distinguish between high and low-quality tempered glass. Standard construction window cleaning techniques on low-quality tempered glass can result in major scratching.
When glass scratches are noticed, it is helpful to observe the direction of the scratches. Many assume that if the scratches are in the same direction as the path taken by the window cleaner's scraper that he is to blame. Often times these types of scratches result from excessive construction debris or defetive tempered glass, and are not the result of the window cleaner's scraper. Upon closer examination, it is often seen that the scratches do not extend from the beginning of the scraper's path to the end of the scraper's path. On defective tempered glass, as the scraper passes over each glass defect, it dislodges the defect and creates a scratch as it is dragged across the glass surface. For a more extensive discussion of this topic, see the Glass Quality section of this site.
Metal scrapers have always been highly suspect for causing scratches. As a result, it has been occasionally suggested that the use of plastic scrapers would be a safer alternative. In an attempt to test this theory extensive testing on new clean tempered and annealed glass samples was done. These tests showed most tempered glass with excessive fabricating debris were scratched by the plastic scraper as well. The experiments also showed that as a result of their use on the defective glass, the plastic scrapers were contaminated with embedded fabricating debris. If this scraper was then used on quality glass, it would result in scratching every window it touched. These tests conclusively showed that the use of plastic scrapers is a destructive alternative to safe metal scrapers.