This has probably been asked a million times. Had a new tub installed today. The tub straps will interfere with my Hardiebacker, which I had planned to run right down to the top of the tub flange.

So I am wondering the best way to handle it. Should I:

  • Hog-out the back of the Hardiebacker where it will hit the straps, so that it rests squarely on top of the tub flange.
  • Add furring strips to the studs.
  • Just place the HB on the straps and accept the slight out-of-plumb condition. This is the situation before, albeit with drywall


I guess I could sister-in some new studs, but that would entail drilling and re-running the ROMEX. Thanks for any advice.

  • Sistering the studs are way overkill, back wall shimming is simple enough, what is the conditions of the side walls? Can they be shimmed without getting into a door? Are all the walls bare?
    – Jack
    Commented Mar 17, 2017 at 4:22
  • 1
    Does the 8/2 cable (40 amp) near the tub bother anyone else? Makes me feel weird but that might just be me. Commented Mar 18, 2017 at 17:57
  • No problem with the romex at all , not sure where you come up with 8/3. But inside the wall is considered a dry location by code so any legal wiring method would be allowed.
    – Ed Beal
    Commented Jan 29, 2018 at 14:33

4 Answers 4


I've never seen a tub with brackets like that. Usually the lip of the tub gets secured directly to the framing. What brand/model of tub is that? Can you find info online? Many tub manufacturers have installations instructions that indicate how things like backerboard should be applied.

Different sources including this Family Handyman article on Backerboard around tub indicate that you should stop the backerboard 1/4" from the top of the tub lip and the tile should canteliver over it to 1/4" above the tub.

If you look at this installation manual for a Kohler tub it tells you to use 1/4" furring strips to extend the backer board over the lip.

If you can find the manual for your tub I'd go with what they recommend. If you can't, or the brackets aren't part of a normal tub install I'd contact the manufacturer of the backer board to see if it's okay to chisel out some recesses for the brackets. If you want the backer to go over the lip use furing strips and chisel out some space for the brackets. You're still going to have an issue with securing the bottom of the backer to framing since the brackets will prevent the screws from going in. I'm not sure the brackets were supposed to be there to be honest.

Also see this post on using some sort of waterproofing over the backerboard What are the pros and cons of adding a vapor barrier behind shower backer board?


Seems to me the screw heads on the tabs are the issue.

Drill new holes and use ring shank very flat head nails. Try to get the tabs as flat to the stud as possible and call it good.


I'd probably just taper things out with several thicknesses of shim above the straps, ending three feet or so up from the tub. You'll never see it in your finished wall.

Otherwise I think I'd be pulling the straps one at a time and chiseling out a bit of the stud to allow them to lie flush. Two easy ways to do so:

  • Using a sharp chisel, drive downward from slightly above the strap location. Once you've shaved out some wood, cut it off flush with the tub flange.

  • Use a sharp spade bit and drill a series of holes into the stud face. If you orient them well you can clear all the wood you need to for the strap.

Be sure to protect your tub from damage due to slips. A chisel or spade bit will ruin your day if it hits the tub.


I'm assuming since you're putting up HardieBacker you are installing tile of some kind. You could either get flatter head screws and then install the HB with the slight out of plumb condition​ that can be hidden when installing the tile, latte the studs flush with the tub, Or you can take a good sharp chisel notch the studs so everything is flush.

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