mounting to block wall 2

[cvg]

I need some ideas on how to mount a flat screen TV on a mounting arm to a CMU block wall. The wall has firring and drywall. The TV weighs at least 75 pounds. What would be the best type of anchor?

 

[Lion06]

I would check a Hilti catalog for non-adhesive anchors into hollow block and actually design them.

I anchored my flat screen arm to wood studs, but still designed the connection, because I don't believe for a second that the arm manufacturer had an engineer design the actual connection to the wall given all of the possible arm positions.

Check out Hilti's catalog and do the design checks.

 

[slickdeals]

Spoken like a true engineer

 

[racookpe1978]

Remeber your "live loads" in this problem: Sure, they're not much (a 75 lb TV plus a 25 lb (?) mount on the wall), but when you twist the TV to adjust it, or bounce off of while hitting your head, or "bump" into the TV on the mounting arm, it's easy to see a short term 120 - 150 lb jolting load on those mounting bolts.

 

[Stillerz]

bolt the bracket to the wall with some hilti anchors then get your old junk 500 pound CRT TV and hang it on the bracket for a week with a piece of cable....if it doesn't, break, put the flat screen up.

 

[jike]

If the block wall has furring and drywall, don't you need to mount to the drywall, not the block wall? How wide is the furring space between the back of the drywall and front of the block?

 

[DWHA]

Try Lindapter anchors. I believe they have an anchor made for connecting to CMU.

 

[racookpe1978]

jike (Structural)
8 Sep 09 12:20
If the block wall has furring and drywall, don't you need to mount to the drywall, not the block wall? How wide is the furring space between the back of the drywall and front of the block?

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To the contrary, actually. IF you mount to the drywall, you're concentrating all of the load (shear and pullout) from the entire load into a very few single point resistance points (the screws going into the drywall from the mount), THEN across the very weak drywall into the very few and extremely weak drywall screws into the furring strips, THEN down the very weak and extremely flexible furring strips, THEN through the very weak and easy-to-ripout screws holding the furring strips onto the block wall, THEN through the block wall to (something) that is (maybe) strong enough to hold drywall from falling off the wall.

Normal furring strip is 1x2 wood (cut at 1-3/4 x 3/4) or 1x4 wood (cut 3-1/2 x 3/4). Sometimes (not often!) a 2x4 is used, but very seldom.

Nope.

Best way is to go THROUGH the drywall at the points where the furring strips and firmly clamp the mounting hardware (the steel strips or mounting column) THROUGH the drywall and furring strip and block into the hollow center of the block wall.

3x or 4x 5/16" or 3/8" toggle bolts will do, or the newer epoxy-in long bolts that seat in both near-side and far-side of the hollow blocks with a flexible "screen" (or bag) that retains the pumped-in epoxy. 4x or 5x 1/4 toggle bolts will probably also work. The lowest toggle bolt resists shear, the reaming resist prying forces when somebody pulls down the TV.

The "bag" bulges out as the epoxy fills it, then as the resin hardens, the resin in the hole itself, the resin around the bolt, and the resin bulging in the hollow of the block wall all retain the bolt from being pulled out.

 

[Stillerz]

By far the best thing to do here is to remove a 24" wide (or whatever width you want) strip of drywall & furring from floor to ceiling and build in a 2x4 stud wall with additional framing provided at the location of the bracket. Then, re-drywall. When finished it will look like a finished pilaster but it will be uber-strong. As a former carpenter of 10 yrs and a BSCE with 5 years of structural design experience, this is what i would do. Seems over kill, but you could also bury your communications and recess your power wires in this new section of wall. you will have the most bad-ass tv bracket of all time with no wires showing.

 

[jgailla]

I was at the local bar yesterday and they have several 40" televisions on brackets attached to the wall.
The bracket is bolted through a 2-foot high by 4-foot wide piece of 3/4" plywood.
The bolts appear to extend through the plywood, through the drywall, and into the studs in the wall, as they are on 16" centers. The bolts looked like 1/2" diameter, and they were spaced four vertically in each stud, spaced about 4 to 5 inches.
Each TV had 12 bolts holding it up, four high by three wide.
They seem pretty sturdy. The brackets weigh as much as the TVs.