Wall mounting fasteners for cinder-block walls.

[itsmoked]

I'm faced with mounting a bunch of 300 pound enclosures on cinder-block walls. I'm looking at a bunch of so called "fasteners" but have little confidence in what I'm seeing as a lot of it is probably marketing BS.

Does anyone have something they actually trust to stick enclosures and Unistrut to Cinder Block walls (or concrete masonry units)?

Got a link or name for it?


Keith Cress
kcress -

http://www.flaminsystems.com

 

[JohnRBaker]

Do you have access to both the 'inside' and the 'outside' of the wall? If so, would it be practical to run lag bolts through the entire wall?

John R. Baker, P.E. (ret)
EX-'Product Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[itsmoked]

Hi John; Nope. In this case the other side is another business.

I'm thinking maybe Tapcons, the blue things. I wonder if I need the larger ones with the square ends or if the more common pointed screws would be fine.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[MintJulep]

Tapcon screws work well

The right size hole made with the right bit and hammer drill are essential.

Anything longer than the thickness into the void is a waste.

 

[catserveng]

What is the installation? If you have large temperature variations or vibration from plant equipment, Tapcons by themselves may loosen. In a lot of the plants we work in, we hang vertical runs of strut to the wall with Tapcons, but run them all the way to the floor to support the weight better, then hang the enclosures off the strut.

Most sites, like wastewater or power plants, we use 1/4" Tapcons every foot. Be careful not to overtorque, the install tool is worth the money if you haven't used them before. On old cinder block we also add a dab of anchor epoxy.

MikeL.

 

[tygerdawg]

Did you consider Red Head sleeve anchors, or similar?
More work than Tapcon but, done properly, will give some serious holding power.

TygerDawg
Blue Technik LLC
Manufacturing Engineering Consulting

http://www.bluetechnik.com

 

[dik]

The CMU wall may not likely take serious holding power.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[TugboatEng]

Most fastener systems are good in shear. How far from the wall is your center of gravity? You only need a little resistance to pull out. These have very good pull out numbers.

https://www.mcmaster.com/Standard-A...t-female-threaded-anchors-for-block-and-brick

Disclaimer: My experience is with adhesive mount fasteners in metal. However, there are some tricks here. One issue is leveling the enclosure to the surface so you aren't using all of your pull out strength to distort the enclosure. I usually put a nut on the stud prior to installing the enclosure and then run the back nuts until they touch the back of the enclosure flange before tightening the mounting nuts.

Expansion type studs require tension to remain in place. Install a spacer and then nut first to maintain tension on the anchor, then install a second nut for leveling before placing the enclosure and final nut. Install the anchor slightly proud so the expansion nut isn't also pulling on the anchor

Finger sketch time:

Purple is anchor, gray is block, red is stud, green is spacer, black are nuts, blue is enclosure flange.

 

[itsmoked]

Thanks all. Looking at your responses I went ahead with Tapcons (my first). The enclosures are 3ft tall by 2 feet wide and I estimate them to be about 300#. I couldn't get my beliefs behind the 1/4" Tapcon and while weighing the 3/8" ones in my hand I stumbled across 5/16" ones! I went with those. I have a very nice hammer drill I'll drill the holes with.


I have to mount the enclosures to short Unistrut then mount the Unistrut to the walls because the customer isn't dead-certain where exactly to put the control panels and fears having to move them again. Mounting them via the Unistut avoids the nightmare of having to remove loaded, wired panels before a move can be made.

tyger; I've used Red Head sleeve anchors lots of times. They make me nervous because occasionally they jam up wrong and boy, that gets ugly fast.

Cat; Never big temp excursions. Central CA coast.... Indoors heated neighboring business. Probably about a 30F swing. I am noting that smart strut-to-the-ground scheme. Thanks!

Over torque... CHECK!

Install tool: Couldn't bring myself to pay $32 for what looked like cheap nut-driver sockets. Maybe I should've looked closer.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[itsmoked]

Tug; Cross post!
Thanks for the key I couldn't figure your drawing out at all until I saw that then it made total sense.

Interesting point on keeping tension to keep the anchor locked in the wall. I'm noting both the pull out and shear are about triple the same size of four-way expansion anchors.

5/16"

650PO 820SH
verses
2,250PO 2,505Shear.

Oh, and that's the bolt in the considerably larger anchor. That means drilling MUCH bigger holes in the masonry. NOW I understand why Tapcon keeps touting "installs faster". The masonry hole size might be all the time difference. A 5/16" anchor requires a 1/2" hole.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[HTURKAK]

I do not know locally available expansion bolts in your region. There are expansion bolts ( hilti universal, fisher injection anchors...)

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1638271329/tips/TSNGOQBEIHILTIUNIVERSAL45_HUD1-3_jntneu.webp[/url]

 

[Artisi]

My initial concern wouldn't be the fixing method, it would be the localised cinder block strength / load etc.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[kjoiner]

Hello,

As HTURKAK mentioned, I would contact Hilti for fastener recommendations.

Kyle

 

[drawoh]

itsmoked,

Have you talked to a civil or structural engineer? My understanding is that brick walls have zero tensile strength. All the mortar does is distribute the load. Maybe your three hundred pound enclosures should sit on the floor.

In my opinion, 300lb structures elevated any distance above the floor, require structural analysis by a qualified civil or structural engineer.

--
JHG

 

[MintJulep]

Allowable loads in shear and tension given here

https://www.tapcon.com/getattachment/c564162c-139b-4c5f-9ce3-242562e2139d/ESR-1671