I uninstalled my old bathroom light fixture to replace it with a nicer light but found that there is no stud and no wall box behind the sheet rock. The old light fixture is very light but the new one is not. Is it safe to attach the new light fixture without studs or wall box to attach it to? Would it be safe to just use wall anchors or do I need to hire a professional for this job?enter image description here

  • Did the old fixture have a built-in box? Jun 30 '18 at 18:36
  • No, it did not have a built-in-box.
    – Martha
    Jun 30 '18 at 20:44
  • Definitely not legal and probably not safe to do this. You need to install a box. Jul 9 '18 at 5:02

I found almost that exact same image behind a bathroom vanity light fixture that I took down to replace. Needless to say I was flabbergasted that such garbage workmanship would be hidden behind a fixture.

You should look very closely at what is just behind the place where the romex cable is coming out one hole and reentering the wall cavity at the slot on the right.

enter image description here

Mine looked exactly like that and there was a stud right behind that cable loop.

I opened up a hole to the right of the stud for a suitable metal electrical box. I then drilled a hole through the center line of the stud from side to side and worked the wire through the hole. I then mounted the electrical box to the side of the stud and brought the electrical cable into the box and secured it with the box clamp at the rear of the box. Now it is properly wired but I had to work at finding the proper lighting fixture that would cover up the messy slot in the drywall. (I would have patched and painted it but decided to wait till I give this bathroom a facelift remodel in the near future.

  • Yes, upon further investigation, there is a metal stud on the left side and about 6 inches to the right, there is a pvc pipe that I figure is part of the bathroom plumbing. I am not sure I would know how to do what you suggested since I have never done this but it does seem like it would be a good option. I may find a handyman to help me with this portion of the project. Thank you!
    – Martha
    Jun 30 '18 at 20:40
  • @Martha - In my case it was a wood stud so that was a lot easier to attach the electrical box to it. With a metal stud it will be a little more complicated. If you do hire a contractor to do this work you should hire a licensed and credentialed electrician. A regular handyman is generally not licensed to do electrical work for hire. On the other hand if this property that you own and you do the work your self it is generally allowed.
    – Michael Karas
    Jun 30 '18 at 20:59
  • This kind of fixture is especially easy to install since one just turns off the wall switch to cut power. (For redundancy one could shut off the breaker.) This is well within the capability of most people if they have some tools and judgement. There are several ways to put in a box on the right side of that stud and use the stud and drywall for support. Installed drywall is quite strong and will easily support light fixtures, except for heavy chandeliers. You might do a better job than most "handymen". If you want to try it, we could guide you. Jun 30 '18 at 21:45
  • 2
    @JimStewart - One needs to be careful regarding a general statement that all you have to do is to turn off the switch to cut the power to the light. (That may be the case for the OP's light). But there are plenty of instances where the power feed comes to the light fixture and then a cable runs to the switch as a simple switch loop.
    – Michael Karas
    Jun 30 '18 at 22:05
  • @Michael Karas she uninstalled the old one without excitement; half the job is done. Jun 30 '18 at 22:23

That's terrible. Whoever did the work did very shabby and unsafe work, and you may have a house full of that.

One option is an "old work" (meaning retrofit) junction box that attaches directly to Drywall, however drywall is basically schoolhouse chalk wrapped in paper soaked in glue, you don't expect it to have any strength. It's a basically useless material except for being cheap, holding up paint and being an absolutely fantastic firestop.

A better option is an "old work" lamp or fan box, which has a built-in metal cross-arm. The cross-arm fits through a sensibly sized junction box hole, but telescopes out 15" so it can bite into the nearest ceiling joists. That is how it carries the weight of a heavy light or the dynamic vibration of a fan. Then the junction box proper is able to clip onto that cross-arm at any needed position. They are quite clever.

  • Thank you so much for your suggestions. I do think this goes beyond my handyperson knowledge and not sure I would know how to tackle it but will probably have to hire someone to at least help me add what is needed to ensure my light fixture can be attached safely and securely. Thanks again!
    – Martha
    Jun 30 '18 at 20:42
  • Assuming a light bar with a clamp at the back and a full metal housing, there's not much difference between this and a recessed light in the ceiling. the cable is secure and safe, and there's no additional fire risk. I assume the cable was routed over the stud in each case because that's where the knockout ended up in the light bar.
    – isherwood
    Jul 3 '18 at 3:46
  • OP reported that there is a vent pipe to the right of the location of the light fixture. Bracing of the box on the right will have to be by the drywall, which of course could be augmented by a thin metal plate or thin plywood on the cavity side of the drywall. @Harper do you think she should use a round box or a rectangular one? Jul 3 '18 at 21:13

I worked as an electrician for a few years. Normally it depends on the light fixture you are mounting. The reason why we just stub a wire out is vanity placement. Sometimes we cant get a box mounted in for a few reasons. Plumbing vent stacks, stud placement, and round cut in boxes(old work) will show around the fixture. If the builder placed a nailer for a round nail on box to be used then its great. Normally they dont. We just use a fixture designed for the wire to be spliced inside of it, and use a romex connector. Then we can center it on whatever vanity it's going over. A plastic box supports weight of the fixture. Its max is 25lbs. I believe a single gang nail-on is 9lbs. Weight shouldn't be a problem. Agreed they should of drilled through the stud and slid the wire through it or at least protected it. I agree it looks shoddy but if a licensed electrician did that they he had a bad day and the wrong light fixture was purchased by the homeowner and not correlated with builder/plumber/electrical contractor for box placement. I hope this clarifies the shoddy look. BTW metal studs require a bushing be placed in the pre-cut holes to keep the wire from chaffing.

  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know how best to contribute here. Nov 16 '19 at 15:06

What you want is called an "old work" box, a type which is designed to be installed into a finished wall from the living space side. Normally you'd get the round one for a light fixture (rectangular boxes are for switches or receptacles) because this will have holes spaced for attaching the light fixture. But look at your light fixture and see what it requires.

Old work boxes clamp to drywall with tabs on the inside of the wall cavity and on the living space side. I prefer the type with the plastic ears that swing out when screws are turned; others prefer the type with a spring metal clamp.

Decide where you want the box and carefully pencil an outline for the opening. It is important to cut the opening precisely according to the instructions for the box because if it is too large the box will not clamp securely to the drywall. Before cutting out the opening stop and consider if you have the hole drawn right.

Cut out the opening with a hand drywall saw, being careful to avoid the wire. To better control the cutting you may want to wrap a rag around the blade, exposing only a couple of inches of the end. Using the rag as a hand grip make short strokes and cut carefully.

Once you have the opening cut look inside with a flashlight. You should be able to work the electrical cable through an opening in the metal stud and bring it out the opening you have cut. I think there will be existing openings in the metal stud. At this point you ideally should patch the drywall so the opening is complete all around. If one of the clamping tabs of the box would fall on the repaired section of drywall, you will have to take care to make the repair sturdy, but it will be hidden by the base of the light fixture so it doesn't have to have a finished look. Any part not covered by the fixture could be sanded and finished later.

Pull the end of the electrical cable out of the opening and pass it into the box with enough extra wire so that when the box is inserted in the opening there will be 5 or 6 inches of wire out past the finished wall. Examine the box and the fixture and determine if the box must be in a particular orientation so that the fixture is oriented level on the wall. (The fixture may have a mounting mechanism which makes orientation of the box irrelevant. If so, you could orient the box so that the clamping ears are not on your repaired drywall.) Only now push the box into the opening and secure the clamps.

More later.

  • Thank you Jim. That information and everyone elses imput has been extremely helpful. I went to the local hardware store and got familiarized with the different electrical boxes available. I am starting to get a better understanding on how to attach this box now and think I may actually try to finish the job myself. My only concern is selecting the right box. Should the box be metal, PVC, or other material? Also, my light is about 10 lbs. Is there anything else I should look for to ensure it will hold the weight?
    – Martha
    Jul 1 '18 at 22:54
  • 1
    I suggest a metal box for this job, as the plastic boxes can flex under the load of a wall fixture. Jul 2 '18 at 2:44

Does your new fixture have any instructions with it? Examine the round blue plastic old work boxes (or octagonal metal boxes?) and see if the mounting holes for the fixture fit correspond to the mounting hardware for the fixture. The diameter of the box must be small enough to fit inside the mounting cover of the fixture. If these conditions are met, buy this box.

Decide on a location for the box. I have never worked with metal studs. There may be a clamp or attaching system which allows a box to be fastened to a metal stud. Use the box or a paper template that comes with it to draw an outline on the drywall for the opening you will cut with a drywall saw. Cut the hole and make sure the box fits (but of course do not install it yet).

Do you have a cordless electric drill? If not, borrow or buy one. You now want to reroute the electric cable through the metal stud. There should be a hole already but if not you will have to drill one about 1/2 inch in diameter. You may have to buy a rubber or plastic grommet to pop into the hole to prevent chafing or cutting of the electric cable. Work the cable through the metal stud and out the hole for the box.

Now repair the hole so that the borders of the hole are strong enough to support the box and the weight of the fixture when it is attached. If the box is to be attached to the metal stud, then this will be stronger, but it may be that the desired location for the box will be father to the right and if so it will be important to properly repair the wall board on the side adjacent to the stud and on the other side.

More later.

  • The light fixture did not come with instructions because it is previously used. The mounting plate is 4" and every round blue box I found does not come in 4 inches. Yes, I have a cordless drill.
    – Martha
    Jul 2 '18 at 1:25
  • If the fixture was previously used, you may not have all the mounting hardware. Could you post pictures of the fixture both sides? The mounting plate may overhang the box but should have holes that allow it to be fastened with screws to the holes in the box. I assume the decorative base would cover a standard box. Is the desired location location right next to the metal stud or is it a few inches away? Will you be able to attach the box to the stud or will there be drywall between the metal stud and the left edge of the box. Note that @A. I. Breveleri suggests you use a metal box. Jul 2 '18 at 3:08
  • I have never worked with metal studs. I suppose some have holes for wiring, some have knockouts, some would require drilling and cutting to make holes for wires? Jul 2 '18 at 15:24

Adding a box with no studs

I wanted to add an electrical box between two studs and not up against one, so none of these approaches worked for me. I found this YouTube video by Jon Eakes though:


His approach is to

  1. Cut an octagonal hole in the drywall the size of the electrical box
  2. Use instant-grab glue to attach 2 pieces of 3/4 inch plywood to the left and right on the back side of the hole (2 per side)
  3. Mount the electrical box by drilling and screwing into the plywood on either side at an angle

In the comments below the video he says that should hold a 15 pound fixture with no issues.

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