Window glass cleaning: Window glazing services can recommend replacement glass with different colors and opacity, and may also be able to install replacement glass mirrors. Specialty. Window, glass and glazing services install glass windows, blocks, doors, walls, and other architectural elements. Some companies also design and install custom glass surfaces and mirrors. Glass windows are used in most residential, commercial, and industrial buildings and differ in terms of shape, size, and type. Glass blocks or glass bricks admit light, but are designed to obscure a room or building interior. Glass doors include a wide range of decorative and functional products. Glass walls may be mirrored, transparent, or opaque. Like glass doors, they are rated for either indoor or outdoor use. Decorative glass mirrors are design elements used on walls, doors, tabletops, and other surfaces. Some window, glass and glazing services install mirrors for automotive applications.