I’m using a studpop (https://youtu.be/Dojw5nakCsY) to detect studs as I’m ready to install a grab bar on my fiberglass shower wall. I’m attaching a picture of my shower wall, where there is a window above it.

So I ran the studpop on that space between the window and the shower wall. I put marks on the blue tape where the studpop ball pops to the center when it detects a nail on a stud behind the wall. What I did was I would run the studpop from left to right then put a mark where the studpop initially detects a nail “left edge”, then move the studpop about 4-5 inches to the right and run it towards the left to get the “right edge”.

However, as you can see from the picture I have four markings on the first stud location (I encircled the marks so they look like eyes just for emphasis). I read that most US homes have studs that are 16-24 inches apart. My condo was built in 1980-1981 so I assume homebuikders follow the same standard through the years. Anyway, the markings show that this stud location seemingly has two studs very close to each other, presumably to support the window right above it. I observed the same situation between the middle and right stud locations as I run the studpop across the same wall within the width of the window. Am I right to assume that each of these three stud locations actually has two studs - which my guess is to support the window that is installed above the shower wall?

If my assumption (two studs in one stud location) above is correct, then am I correct to assume that the vertical line marking on the tape would be the center of the “second stud” in the first stud location?

Thanks in advance.

Update: I am adding pics of my bathroom because Jim noticed those tiles and he thinks they are ceramic tiles. All along I thought this is just part of the design. The shower stall was already in place when I moved in in 2002.

bathtub and shower stall enter image description here

shower wall is facing window


2 Answers 2


If you want to use Wingits, here is what you would need for a high quality installation for tile on drywall without using studs. Wingits and drill bit The special hardened steel Wingits 3/4" drill bit would easily cut through standard bathroom tile (and drywall or cement board underneath) and be the exact right size.

A standard hole saw would not cut through tile and maybe not cement board. Try to make sure there is no stud in the way of where you want to drill the paired 3/4 inch diameter holes for the double Wingit. That would mean getting a proper stud finder. You don't want to bore out a 3/4" hole in the tile and hit a stud or have the hole right next to a stud so the Wingit can't expand.

One benefit of boring a 3/4" dia hole is that it is easier to see into the cavity to insure that there are no wires or pipes that the Wingit would contact and damage.

If you would get a proper stud finder, you could find the king and jack studs on the outsides of the window and find a bar that would allow attachment to a stud. This would allow using the stainless steel screws that come with the bar on both ends. But if the studs are not where you want to place the bar, you could screw one end of the bar to a jack or king stud and, if the other end doesn't fall on a stud, you could use a Wingit on that end.

  • What length of grab bar do you want to place on the long wall? I have used both 36" and longer (42") on the long wall. You should also install a vertical 16" or 18" bar above the edge of the tub at the end of the tub used for stepping into the tub. Consider getting rid of the glass wall with sliding door. A shower curtain on a spring loaded rod is much better for the elderly . . . or anyone IMHO. But if that is too much for you right now, put a horizontal 16" bar on the end wall same height as the long bar so that a person entering can grasp it before stepping over the tub edge. Mar 21 at 15:06
  • I don't think a vertical bar to aid entry will work with the existing glass wall because that is where you would want the vertical bar. I put in a vertical 16" bar in our tub/shower but I wish I had put in a longer one up to 36". A longer bar helps in getting up from kneeling beside the tub for cleaning the tub or washing the dog. Mar 21 at 15:22

On just a plain wall with no windows/doors the standard 16 or 24 inch spacing works well.

When you start adding windows/doors, there is a king stud going up to the ceiling and a shorter jack stud joined to the king to hold the header on both sides above the window/door.

There usually have short/cripple studs under and maybe above the window to act to hold the bottom rough frame and for screws for drywall. They might not be at 16 inch centres but should be close depending on the width of the window.

There is usually a stud at the wall corner for nailing drywall to, which might closer than 16 inch centre.

  • 1
    If you see Youtube videos on how to frame a window opening, you will see what to expect. Generally, the doubled studs are just outside the window opening. The purpose of the special pattern of studs around a window is to support the vertical downward forces on the top plate. The king stud/jack stud pairs just outside the window support the "header", a strong horizontal member above the window. Inside the two jack studs (below the window and often above) are short studs called "cripples". Cripples are usually single studs and make good attachment points for wood screws for grab bars. Mar 19 at 17:40
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    Stud finder results can be hard to interpret. I have had false positives on the presence of studs. I once drilled through ceramic tile on cement board and encountered a void where I expected a stud. Mar 19 at 18:04
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    The magnetic stud finder you are using detects steel nails and steel screws. It does not tell you the nature of the wood into which the nail or screw is driven. Unless this grab bar is very urgently needed, take some time to understand the best bars to use and the best/easiest way to install tem. Mar 19 at 18:13
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    Two cripples (right hand marks on your picture) are unlikely. (One is quite possible.) The left hand marks are good identifiers of two studs. Are you setting the grab bar vertical? If so, just use the studs going down from the corner of the window. If horizontal or thereabouts, look to the other side of the window: it’s framed the same. Mar 19 at 19:58
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    The OP should add a wider angle picture showing the overall layout in one picture. In discussion the OP stated the motivation for installing a grab bar is for a visiting elderly person who may be using a shower seat. In that case it is likely that the existing sliding glass door and fixed glass panel should be removed and a shower curtain installed. I am elderly and use a shower curtain. Mar 19 at 20:27

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