Joists are beams or studs found on the ceiling of the house. Whenever you want to install a fan, light bulb or decorations on the ceiling, you must know where they are located. One advantage of locating joists is that building standards require them to be uniformly spaced. Most of them are placed 16 to 24 inches apart.
For a flat ceiling surface, a stud finder is the best tool to use; you can sample some of the top models at Stud Locator. If the ceiling has an irregular surface, you may need to use some more complicated methods to locate the joists. Irregular ceilings are common in most buildings and using a stud finder on them can be impossible. The surface may interfere with the finder’s sensor and damage its surface. A ceiling that is unevenly insulated also interferes with the performance of the stud finder. You can place a cardboard on such a ceiling to create a smooth scanning area or invest in a multiscanner, which is capable of accommodating any type of surface.
The process of scanning the ceiling for joists or studs is almost similar to the one used to detect wall studs. It is as follows:
- Place a ladder on one of the walls and use it to access the ceiling.
- Hold the stud finder close to the ceiling and calibrate it basing on the manufacturer’s guide, or at an area which has no joist.
- Using a measuring tape, measure a distance of 16 inches from the edge of the wall. Move the finder around this area and when it beeps or lights up, mark this as the edge of the joist. Use this edge to determine the exact center of the joist. If the stud finder does not locate any joists, increase the distance to 24 inches.
- Once you detect the first joist, measure an interval of 16 or 24 inches from it and move the finder across each area to detect the rest of the joists on the ceiling.
If your ceiling is one that sheds dust on touching or drilling, you will need to put on a dust mask. In case you do not have a stud finder, you can use the tapping and test-hole methods to locate the joists. When using the tapping method, pay attention to any changes in the density and sound produced by the ceiling as you tap. Once you detect any change, drive a nail to the area to find the exact location of the joist’s centre and edges. Repeat the process at 16 or 24-inch intervals to find the other joists. Do not guess the intervals as some constructers always ignore some building standards, including the even joist spacing rule.