1

So, I've read through a bunch of stuff online for mounting a pull up bar to a cinder block wall and before I go out and rent a hammer drill I want to see what would be the best anchor system for my specific scenario.

I plan to mount the bar in my garage. It is cinder blocks, but until I drill I'm not certain whether it is hollow or if the blocks are filled. In either case, it is a load bearing wall as on top is a cement slab, over top some sort of metal sheeting. I do have access to the other side of the cinder blocks both from the outside and the inside of the house, but would prefer not having something sticking out the other side if possible.

I'm not sure if I can just use 3/8 in. sleeve anchors, or if it would be better to mount some 2x8's vertically with cement screws and then bolt into those, or drill all the way through the wall and then bolt it through that way. I just want to make sure it is safe and secure for years to come.

I'm reasonably handy, but I've never really drilled and mounted into concrete and I know this is a somewhat special case due to the inconsistant force being applied.

Pull up Bar Image

  • 2
    I don’t like any kind of toggle bolt , anchor bolt , red head or sleeve anchor on a load that is less than static in a block wall!!!!! I would be putting a large piece of plywood on the wall anchored to the block and use that to support the pull-up bar. Block is brittle and will not last without additional support in my opinion. – Ed Beal Jan 1 at 1:47
  • 1) You need to consider the dynamic load, 2X or 3X? 2) Don't assume that the load will be evenly distributed between the sides. 3) Consider what will happen if it fails. Using it as intended: sprained ankle? broken leg? ... What if someone hangs from their knees: Broken neck? – Mattman944 Jan 1 at 3:50
  • I installed a similar attachment to this in my closet on an exterior block wall. I used 3/8" toggles with 3/8" threaded rod , washers and nuts. I did not use the 8 holes but only the top hole on each support. I was lucky and got the hollow portion of the block. It hasn't budged in 35 years. – JACK Jan 1 at 14:31
  • @Jack Appreciate the feedback from an actual install! – Dakcenturi Jan 1 at 16:20
  • 1
    If and when you do use a hammer drill on a CMU for any type of expansion anchor try using the hammer drill on the spin only. Often the hammering will just destroy the block. – NoSparksPlease Jan 2 at 1:45
0

I installed a similar attachment to this in my closet on an exterior block wall. I used 3/8" toggles with 3/8" threaded rod , washers and nuts. I did not use the 8 holes but only the top hole on each support. I was lucky and got the hollow portion of the block. It hadn't budged in 35 years.

0

The problem can be divided into 3 parts:

A) Determine the static pull-out force.

B) Determine the dynamic to static force ratio. My gut feel is 2X to 3X, but I have nothing to back it up.

C) Determine the appropriate fasteners and/or additional interface.

This is only an answer to part A.

The problem is much easier to solve if a few simplifications are made. I have re-positioned the diagonal, this is OK because we don't care about the compression force in the diagonal member. Each member can now be considered to be a strut of a simple truss (tension or compression only, no torque).

The geometry determines the forces. The static pull-out force at the top is the weight of the person multiplied by the ratio of the dimensions (projection/vertical).

250 lbs * 30"/24" = 312 lbs

enter image description here

  • I'm only 210lbs so that reduces this a bit. In any case, I know the safest option would be to drill all the way through and set bolts on the outside of the wall with a small steel plate to distribute the force, but that is definitely not optimal. I'm wondering if, while not very aesthetically pleasing, running a 4x4 from the ground up to the overhand of the bar, just to minimize the down ward pull would make it feasible to just utilize sleeve or toggle anchors. – Dakcenturi Jan 1 at 16:28
  • 1
    If you are going to use wood, run it all the way to the ceiling. Pull-out on the top is the risk, not the down force (shear). The higher that the screw into the block is, the less pull-out force it will have. I would probably use 2x6s. – Mattman944 Jan 1 at 17:17
0

I would use 3/8 toggle bolts. At 50 inches, you should be able to hit the hollow part of the blocks. If they aren't hollow, then great, go with sleeve anchors, which should be fine according to the calculations above. I used to see old tube type TV mounted in classrooms to blocks all the time.

-1

I think you're over thinking this. You have 4 mounting holes across the top, which is going to want to pull away from the wall when you hang from the bar. I'm not concerned about the shear (straight down) force as you have 4 more bolts along the bottom to help with that force.

Not sure how much you weigh, but let's say you're a big guy, 250 lbs. That's 62.5 lbs per fastener along the top. According to the Concrete Fasteners website, a 1/4" sleeve anchor embedded 1" has a pull out strength of 682 lbs. See table below.

enter image description here

With 4 of them the pull out force would be greater than 2700 lbs.

Mount the bar directly to the wall. Why bother with an intermediate support like the 2x8's you were talking about?

Edit 1 1/1/2010:

Updated my back-of-the-envelope estimate for the pullout force on the upper connectors. Here's the analysis-

enter image description here

Top diagram is the exercise bar with dimensions and the 250 lb load

Second diagram depicts the upper, horizontal bar and the brace. The arrows indicate the various forces acting on the pinned joints A & C.

Method used was to sum the moments about A that, because it is pinned, have to equal zero, and solve that for the reactive force on the brace, Rc in the diagram.

Once I have Rc, I can solve two more equations to get the reactive forces on A. Rx has to equal, in magnitude, the pullout force on the top of the bar. Rx works out to be 312 lbs, just like Mattman showed in his analysis.

Honestly, I was surprised our answers were identical, given that Mattman had made some simplifying assumptions.

Anyway, we're now at 312 lbs total pull out force on the top of the bar, or 78 lbs per fastener, or about 20% higher that my original estimate. Even with a 2X or 3X margin needed for shock, I don't think that's too much for a wedge anchor in a hollow block. But I don't have anything solid (no pun intended) to base that on.

  • You do not want to rely on the “shell” of the concrete block. The shell is a maximum of 1 1/4” thick and the expansion anchor will not hold. That chart is probably for 3,000 lbs. concrete...not cinder block. Also, a 250 lb. man hanging 30” off the wall generates more than “62.5 lbs. per fastener along the top.” (250 lbs. x 2.5 ft = 625 foot lbs.) You need to anchor to a reinforced core of those cinder blocks. – Lee Sam Dec 31 '19 at 23:45
  • 2
    I would mount to wall too but have a few 3'8" toggle bolts handy. I doubt that the cinder blocks are concrete filled and I'm pretty sure values above are for concrete, not block – JACK Dec 31 '19 at 23:53
  • @Lee Sam & Jack - The chart was for 2,000 lbs concrete – SteveSh Dec 31 '19 at 23:57
  • 2
    Impact force from the change in direction will be multiplied by the distance from the wall. I have never seen many pull-ups or chin ups done with out high shock at the bottom. Block walls , much different than concrete, a large plywood attachment to distribute the shock and weight with a live load would better! – Ed Beal Jan 1 at 2:05
  • 1
    often there's a bond beam in a block wall, ths is a row of blocks with open ends filled with a solid course if concrete and reinforcing bar. this will be near the ceiling. depending on the ceiling height you might need to install the pull-up bar upside down, connecting the struts to the bond beam with 3/8" wedge bolts and the arms just to hollow part of wall. – Jasen Jan 1 at 22:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.