It did not occur to our architect, builder, or any of the subs to mention that it might be a good idea to install blocking for cabinetry or bathroom towel/grab bars before sheet rocking. I think it would have been a very good idea to do this. Not such a big deal with cabinets, because not too hard to hit studs with those, but quite important for grab bars, which are likely to not land on studs, and also maybe for towel bars, though loading for those will not be too bad.
So I didn’t want to cut the walls open to install blocking for towel bars. Our bathroom fixtures are all Hansgrohe’s Axor Citterio M in satin nickel. Hansgrohe bars look OK but are expensive and long lead time and squared off. We decided to go with Valsan’s Porto line, which has round rods and is modern looking and available in a satin nickel, moderately priced and readily available.
To mount I consulted the many photos I took before we sheet rocked and used my handy neodymium magnet stud finder, along with wall panel shop drawings, to figure out what was where. Where I could mount to studs I used 1.5″ GRK cabinet screws. Where I was not going to catch a stud I used Everbilt hollow wall anchors, I think these are considered to be molly bolts and seem to be the best way to secure things securely to sheet rock. Our sheet rock is all 5/8″, so needed the longer anchors for this. I think the shorter anchors may have worked, but the boxes for same call out max thickness of 1/2″. Home Depot had these anchors (Lowe’s did not, nor did a good local hardware store).
Theoretically you can just drive these anchors through the sheet rock, but you would have to pound the heck out of them for this. Our sheet rock is already poorly fastened because studs were all over the place and driving these through would have caused a lot of damage. I already popped a few sheet rock screws fastening the towel bar fitting to studs. I forget what drill size I finally used, but I worked up to a size where it was pretty easy to tap the anchors through the hole. No problem with the anchors spinning as they were set, the barbs held plenty well in the new sheet rock. I would not want to hang anything hugely heavy on sheet rock, but a couple of towels on 5/8 should be fine. I put of a couple of hotelier racks like this too and am not too worried about them either.
No grab bars for now. If those don’t happen to land on a stud I think we are cutting the walls open to block for those. We’ll wait until we are a bit older …