Is my analysis of a closet system (rails hanging from a top track) correct? (e.g. Elfa, IKEA Algot, or floating shelf on L brackets)

So my contractor didn't use the supplied anchors from the closet company (Elfa), and now I don't know if the random anchors they used will hold up, and wanted to know if I should re-mount the tracks with better anchors.

(This is a representative pic from the site in the watermark--Red circles are where I may support rails from the bottom with a block of wood or something, since they almost touch my square baseboard)

More pictures of the system: https://i.stack.imgur.com/nqIND.jpg

After a bunch of research, and using these links as resources:

https://physics.stackexchange.com/questions/601974/is-this-the-right-way-to-calculate-the-force-on-a-screw

Physics - Mechanics: Ch 15 Torque (20 of 25) More Examples: 2 F=? of Screw on Bracket - iLecture Online https://youtu.be/kkgj5QBF_Tc

I drew this diagram of forces (free body diagram?):

I simplified the actual closet system to one with just one anchor and one rail (assuming weight will be evenly distributed). Point A, the bottom of the rail is the point of rotation.

(Please tell me if this approach is ok for the purposes of this analysis)

And made this spreadsheet to help calculate things using the torque/moment formula:

T = F * d

And that the sum of T should be 0.

F1 = force on shelf (assume at front edge) F2 = force on anchor

Then, F1 x d1 = F2 x d2

F2 = F1 x (d1/d2)

My results are that with a 50lb rated anchor I should be able to support at least 100lbs safely (dividing the formula result by 2 for safety) on that anchor-- does this seem right?

The rails are very long (80") so I suppose that plays into it, but want to make sure I'm not missing anything.

If this is correct, then basically it means that the closet system should be fine on even average 50lb rated drywall anchors, and if I use heavy duty toggle bolts, there should be no worries under typical closet loads?

EDIT:

It occurred to me after posting this that perhaps what I'm missing is the vertical shear force on the anchor? If I support the rails from the bottom (so the rails are basically sitting on the wood baseboard), that would eliminate that concern, right?

EDIT 2:

After having a chance to get on-site and take a closer look, found a few things:

1. Does not appear that any anchors are in the studs, will go back this weekend to check again with an endoscope, cut open the drywall or use finish nails to double check.

2. It seems the top tracks were glued onto the wall, after removing all screws in the track, I cannot budge it, even prying with a screwdriver. The main reason I would remove it is to remount right-side up, but the only difference would be some cut out slots that let you slide in rails from the top. I was able to get rails in from the bottom, and can leave it upside down as long as there's no concern for bending the small portion of the rail that's next to the slots. (Can see in picture)

3. My new plan is to drill another hole or two through the top track to get into metal studs once I locate them, and secure with snap toggles. And also find something to place on the baseboards to support the rails from the bottom (any ideas? coins? folded paper/cardboard?). Any other issues I'm missing with this plan?

More pictures of the top tracks and my setup: https://i.stack.imgur.com/4T7N7.jpg

Thanks for everyone's replies!

• Key question/information missing? what anchor type did they use ?? picture please Jul 21, 2022 at 21:57
• what is the spacing between vertical rails Jul 21, 2022 at 21:58
• What anchors did the contractor use, and what type did the instructions call for? Examine that and not all the mumbo jumbo.
– JACK
Jul 21, 2022 at 21:58
• I would probably toss the anchors and just use #10 or #12 2 inch or 2 1/2 inch screws into the studs. No math needed and should hold a tank. Jul 21, 2022 at 22:09
• The vertical rails hang from the top horizontal support. Which often can be screwed directly into the header. Rock solid - we have several such setups heavily loaded still up years later. Jul 22, 2022 at 15:30

Using bottom screws will defeat the purpose of hanging adjustable space rack.

Insert small piece of foam between the rack and wall to prevent scratches.

Starting from the corner of the room, measure 16 inch, and observe if there is a screw in the top rail.

Repeat measurement for next screw and so on.

That would indicate they used studs (and no anchors), which would be the strongest hold.

• I was thinking of supporting from the bottom with a block of wood or something, rather than bottom screws. Point A is just where the rails touch the wall. Jul 21, 2022 at 23:44
• @vlotty please measure the spacing between the screws, not between the railing. Jul 22, 2022 at 0:00
• @ruskes is right that the elfa system relies on the top rail to support the load. Screws in studs (or possibly the top plate) in the rail are more than adequate. Elfa’s supplied drywall fasteners are fancy, but they are really only holding the uprights in alignment. Jul 22, 2022 at 0:51
• @Ruskes Sorry, I misunderstood-- I will be on site this weekend to check for where the screws are and measuring to see if they line up with where studs should be (and will bring a stud finder just in case). Appreciate the answer Jul 22, 2022 at 1:10
• @Ruskes Just added an edit-- did not appear that any current screws hit any metal studs Jul 26, 2022 at 21:16