Re: Installing a living room light
Do you have access to the ceiling from above? If so, you simply mark the location you want to install the fixture with a nail, then find it from above and adjust to suit installation as necessary.
If you're hanging a simple light fixture, then installing a light box on a stretcher bar between the joints is sufficient. If you're going to hang a fan, then you either need a fan rated joist box attached directly to the joist or you need a stretcher designed for fans.
You then need a power source and to run a switch leg. Interior walls typically are obstruction free and no insulation, making them the best candidates for fishing new wires in from above.
With attic access you can typically install an overhead light with no damage to the ceiling or walls. There are some instances, such as blocking within the wall that can cause problems, but a small access hole is easily patched, perforating your ceiling and wall as you suggest is not.
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