Glass Expert Analyzes WIndow Damage

Glass failure analysis expert analyzes scratched windows on new construction. There have been numerous occasions where a glass expert has been brought in the determine the cause of window scratching. This is often on new construction that has a stucco exterior. Post construction window claening is critical because of adhered construction materials. Removal of these materials is difficult because of their adhesion. Therefore, cleaning crews should not use blades to remove debris. In many cases abrasive debris such as stucco or cement can be captured by the blade and scratch the glass as the blade is being drawn across the surface. Abrasives can also be captured by dry cloths and pads and can also cause window scratching. The photographs above show the resulting window scratches. Upper left is a sample of cloth related window scratching, and upper right is a sample of metal blade related window scratches. These are window cleaning related and are not manufacturing defects. Only experienced window cleaners should be assigned to clean windows on new construction.

WIndow Defect Analysis

Glass failure analysis expert witness has analyzed numerous cases of window damage. Often a metal blade is used by the window cleaners. In many cases the window damage is found on new construction. GANA has specific window cleaniong instructions that forbid the use of metal blades. The concern is that the blades pick up abrasive particles that get between the blade and the window glass and cause glass scratching when the blade is moved across its surface. In the case of scratched tempered glass, there is a consern that glass particles have attached themselves to the window surface during the tempering process. Later cleaning will dislodge these particles and they will cause scratching. The california failure analysis expert has examined unscratched clean windows that have streaks that were shown to be adhered glass particles. This observation proves two things:

1. Cleaning tempered windows with adhered particles can be done without scratching. Use of a blade during cleaning of tempered glass will cause scratching and the abrasive is not necessarily adhered glass. It can also be dirt or abrasive materials such as concrete or stucco.

2. Microscopic examination can be used to determine if there are glass particles stuck to the surface of tempered glass.

Above are two microphotographs of a tempered glass surface found to have adhered glass. Upper left is 25X magnification and upper right is a 200X magnification. This window was cleaned before the pattern of adhered glass was discovered. Tempered glass window cleaning defects can be avoided even when there are adhered glass particles. On ther other hand, it is extremely risky to use metal blades for window cleaning if window scratches are a problem.

Glass Failure Analysis Expert Discusses Metal Clad Wood WIndows

Glass failure expert re-visits the window reliability of metal clad wood windows. Recently, numerous entities are suing various window manufacturers because of premature window failure (i.e. poor window reliability) of various brands of metal clad wood windows. These window failures are not manufacturer dependant; they are a result of the fact that these are metal clad wood windows. At issue is the fact that water can breach the caulk seal of the metal cladding and saturate the wood. This inturn causes the wood to expand and compromise these seals further. The trapped water cannot escape and as the window heats in the sun, the wood rot occurs (the wood composts), and the window structural integity is compromised (see the photographs above). A degraded window cannot prevent water intrusion. This window damage can happen rapidly (less than 3 to 5 years), and it is hidden from view by the metal cladding. Window reliability is poor and the chance for significant storm damage to a home is very high

Glass Damage from Weld Spatter

At a new condminium complex, numerous windows were discovered to have been damaged by weld spatter. Upper left is a photograph of typical damage found on the affected windows. A glass expert examined the damage to determine if the windows could be repaired. A glass failure analysis was performed to evaluate the damage level. Microscopic examination showed that the damage was below the surface. The damage depth varied from 0.05 mm to 0.3 mm deep. The photo on the upper right is a 20X photo micrograph of the glass damage. The round part of damage is 0.3 mm deep. The failure analysis expert deems these windows unrepairable. They must be replaced.