| You don't have to open the whole ceiling to run perpendicular. Either buy or borrow a right angle drill or buy a right angle adapter for your drill. Determine the location of each joist. First is hardest after that uniform spacing should tell where the next one is. Now make a hole just large enough for the right angle drill on one side of the joist and dill a 3/4" hole in the joist at least 2" up from the ceiling.. You should only need to make 3 or 4 holes for an average size room. (There needs to be only one per joist.)
Tip: use a short shank spade bit just long enough to go through to keep hole size in ceiling as small as possible. If no short shank spade bit available use a hole saw that drills deep enough to go through joist. |