A line laser is an electronic device that produces a visible horizontal or vertical laser beam line across a surface, such as a white wall. The most common application for this device is within the interior construction industry; workers can align floor joists, door frames, and tiling panels with a properly set up line laser. Laser manufacturers have designed different variations of the device for easier use during the work day.
The basic line laser available in the marketplace produces a simple horizontal line from a small yellow housing. An internal diode emits a powerful red light that is spread into a visible line as it exits the transparent outer housing cover. Workers will typically attach these lasers to a tripod or acoustical ceiling grid; the horizontal line provides a level reference for workers to align interior construction materials within the designed specification.
Another line laser variation emits a horizontal and vertical beam in a cross line formation. Similar to the setup for a horizontal only line laser, this device's vertical laser emission offers a reference for a 90 degree plumb line. The plumb line is extremely important in construction since it complements the perfect horizontal level by forming right angles at building corners; improper interior corner angles can contribute to poor construction integrity of the structure.
Other laser models allow the user to alternate between a horizontal and vertical line, rather than using both lines simultaneously. Buttons provided on the laser's outside housing indicate the line mode chosen; toggling through the modes is possible until the worker finds the needed function. This versatility is important in construction since some jobs may be in small spaces or structures; any laser light that is not necessary for aligning the construction materials may distract workers or cause errors. The ability to use only the light needed for layout is essential for a safe working area.
An alternative form of line laser is referred to as a rotary model. These lasers do not emit a stationary line across a surface; rather, they have rotating heads that emit a diode's light in a 360 degree pattern, effectively creating a ring of level, horizontal light. Rotary line lasers are useful in larger construction projects where a level line is needed along all four walls of a room. In contrast, some rotary line lasers can be placed in a vertical position; this plumb ring of light is especially helpful for aligning tile edges for flooring layout.