# Suspending something heavy from a concrete beam **URL:** \ **Category:** Factual Questions\ **Created:** [June 18, 2009, 10:42pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227 "2009-06-18T22:42:33Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [June 18, 2009, 10:42pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/1 "2009-06-18T22:42:33Z")
I got myself a nice 65kg boxing heavybag and the most suitable place to mount it is a reinforced concrete beam in my bedroom. I am thinking of taking a sheet of metal of sufficient thickness, welding a hook in the middle, drill some holes and attach it to the beam with concrete anchors like these: [http://www.supplierlist.com/photo\_images/71313/Wedge\_anchor.jpg](http://www.supplierlist.com/photo_images/71313/Wedge_anchor.jpg) Is it safe to drill a load bearing concrete beam to insert those anchors? The beam cross section is 25 by 45 centimeters and I guess there’s about 1 cm of mortar covering the actual beam. How deep should I drill? ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [June 19, 2009, 12:26am UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/2 "2009-06-19T00:26:31Z")
I wouldn’t fuck with the tension side of a load bearing composite beam. I’d rather put shallow expansion bolts near the top-side of the beam (maybe 25 mm deep) and hang the rig from the compression side of the beam. 65kg ain’t such a huge load but include footage of the building collapsing if it all goes wrong.l ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [June 19, 2009, 3:31am UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/3 "2009-06-19T03:31:39Z")
I’d just use a single anchor drilled right into the bottom of the beam (that is, drill straight up into the beam). It’s pretty common to use anchors in concrete like that to hang stuff like pipe hangers, uni-strut, cable trays, etc. in buildings. How deep you drill depends on the anchor you use. ---
**Author:** ![TastesLikeBurning](https://avatars.discourse-cdn.com/v4/letter/t/839c29/32.png) [@TastesLikeBurning](https://boards.straightdope.com/u/TastesLikeBurning)\ **Post date:** [June 19, 2009, 3:37am UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/4 "2009-06-19T03:37:26Z")
Another thing to consider is whether the anchors you’ve chosen are suitable for hanging something that will move (with considerable force). ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [June 19, 2009, 4:44am UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/5 "2009-06-19T04:44:35Z")
If it is pre stressed concrete do not drill to deep with out an x ray. I would not mess with it, and if you must on the sides near the top. ---
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [June 19, 2009, 7:28am UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/6 "2009-06-19T07:28:03Z")
AFAIK it is not prestressed. Compression side is the top side right? It is not practical to drill that high. I was thinking somewhere around the middle. Anyway, I ordered a U shaped sheet of metal. The idea is to put it so it hugs the whole beam and then drill 2 holes at each side and put the anchors. Then I am going to weld a ~30 cm rod (parallel to the floor) and hang the bag from there because there is not enough space to hang it directly below the beam. ---
**Author:** ![butler1850](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@butler1850](https://boards.straightdope.com/u/butler1850)\ **Post date:** [June 19, 2009, 2:31pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/7 "2009-06-19T14:31:38Z")
Why not take that U shaped piece, and hang it over the beam. Connect the sides with a set of long bolts, and suspend the bag from the middle one (if using pick one, if you’re using less)? Something like this: ```auto --- |b| |b| -------- <-Rod ||| | bag ``` No drilling, easy to move to a new location. ---
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [June 19, 2009, 3:22pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/8 "2009-06-19T15:22:52Z")
There’s no gap between the ceiling and the beam so this is not possible. This is what I am thinking. The thick lines are the ceiling and beam. [http://img10.imageshack.us/img10/6660/dokari.gif](http://img10.imageshack.us/img10/6660/dokari.gif) ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [June 19, 2009, 3:26pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/9 "2009-06-19T15:26:16Z")
Are you the building owner? Do you have adequate insurance? ---
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [June 19, 2009, 4:12pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/10 "2009-06-19T16:12:44Z")
Yes, I am the owner. Insurance? In case the building comes down? 😃 ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [June 19, 2009, 7:12pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/11 "2009-06-19T19:12:57Z")
What is the ceiling made out of? ---
**Author:** ![Hyperelastic](https://avatars.discourse-cdn.com/v4/letter/h/a3d4f5/32.png) [@Hyperelastic](https://boards.straightdope.com/u/Hyperelastic)\ **Post date:** [June 19, 2009, 9:15pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/12 "2009-06-19T21:15:11Z")
I would really advise against this. But if you absolutely must hang your bag from the beam, get or make a very large (big, big area) U-shaped bracket and bond, do not bolt, it to the beam using something like Araldite. ---
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [June 19, 2009, 9:44pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/13 "2009-06-19T21:44:35Z")
> [@Dag\_Otto](#): > > What is the ceiling made out of? The ceiling is concrete too ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [June 20, 2009, 2:04am UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/14 "2009-06-20T02:04:50Z")
Leave the beam alone and put the expansion bolt directly into the ceiling. This is a common way to hang mechanical equipment. ---
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [June 20, 2009, 5:23pm UTC](https://boards.straightdope.com/t/suspending-something-heavy-from-a-concrete-beam/500227/15 "2009-06-20T17:23:09Z")
This is the U-shaped bracket I am talking about: [http://img44.imageshack.us/img44/68/img9797.jpg](http://img44.imageshack.us/img44/68/img9797.jpg) This is the beam where it will be attached (some mortar was scraped off when I slipped the bracket on the beam. It fits nice and snugly): [http://img14.imageshack.us/img14/1750/img9799w.jpg](http://img14.imageshack.us/img14/1750/img9799w.jpg) And this is the heavybag: [http://img7.imageshack.us/img7/8708/img9801r.jpg](http://img7.imageshack.us/img7/8708/img9801r.jpg) A friend will bring his heavy duty drill on Monday to make the holes. If the roof of my house doesn’t fall on my head, I will post pics with the heavybag in place.