Hi all!

I am having difficulty mounting a full motion TV wall mount to my wall. The wall mount is a Sanus VMF308 and the TV is a 40" Sony EX640. The mount weights about 60 lbs and the TV weighs about 30 lbs. The mount is designed to hold up to a 60 lb TV. The mount comes with 3" lag screws which require a 7/32" pilot hole for mounting to studs and with 2 3/8" plastic anchors which require a 3/8" hole for mounting to concrete block or solid concrete.

Here are the issues:

1) I am installing the mount over a 70" couch (which is not the primary couch in the room). In order to keep the mount centered screwing the mount directly to the studs is not possible. The mount would at best be 5" off center which when we are talking about a 34" wide TV in a 70" space would be very noticeable. For the record the rest of that wall is taken up by an upright grand piano (an upright piano with the string length of a baby grand meaning that it is pretty tall).
2) From everything I have read because this is a full motion mount it needs very very strong mounting points and I can not find hollow wall anchors which are anywhere near strong enough which only require 3/4" of depth behind the drywall.
3) It turns out (more about this later) that the walls are 5/8" drywall (guesstimate) on top of 3/4" deep studs on top of concrete block.

So I guess I have a kind of hybrid wall.. . One that is neither traditional stud framing nor traditional concrete/concrete block.

First off if you even know what this situation is called and the only thing you can tell me is that this is called an XXXXX YYYYY ZZZZZ type of installation you will have already helped me greatly because I do not even know what to type into an internet search engine to find more information.

The bottom line is that I need to know how to mount this full motion TV mount to a hybrid wall. If you know exactly how to do that without reading further then you can stop reading here. LOL

Be warned here comes the long story!

I was initially thinking (before I realized the depth of the studs was so short) that there are three mounting slots in each corner of the mount. In addition to those there are 3 holes along the top and bottom of the mount. When I line up the mount to be centered one set of these additional holes lines up with the middle of a stud.. . So I was thinking that if I go out and purchase the strongest hollow wall anchors I can find I can add some additional strength by using these additional holes and the supplied lag bolts.. . So great problem solved. I went to the local home improvement store and found a product called WingIts which advertise themselves as the "World's Strongest Fasteners" which are rated to 300 lbs in all directions. So I purchased those and the recommended 3/4" drill bit (I could not remember if I had one at home and wanted to save a trip). I lined up the template right in the middle and marked everything and I was off to the races. I drilled the 3/4" hole in the drywall only to find that my studs were only 3/4" deep. Measuring from the outside of the package the WingIts are about 2 7/8" deep.. . So they would clearly not fit. My next thought was to perhaps drill through the concrete block to the required depth; however, it seems to me that would greatly reduce the spread of the WingIts which would in turn reduce their strength to the point that the mount would not be secure to the wall. So I discounted that idea. So I ask you experts was I correct to discount that option or is that a viable alternative?

The next thing I considered was to use the plastic anchors supplied with the mounts however I am not sure if that will work properly. Since the plastic anchors are obviously designed to be used with hollow cinder blocks they are surely strong enough.. . But it seems to me that they are designed to be used with the first 1" (or whatever the wall thickness of the concrete blocks is) in the block . . . they are not designed to be used with only the last 1" of the anchor in the concrete block. I know there will be some expansion of the plastic anchor in the drywall but it does not seem to me that there will be adequate strength there. So I also ask you experts if using the plastic anchors through the drywall and through the block is a recommend alternative?

I read about (before I came here) some kind of epoxy that one can apply to concrete wall anchors for additional strength.. . Is that something worth considering?

Even if I were to punt and screw the mount into the studs I am still not sure what to do (and for the record this would only be considered as a last resort) because the 3" lag screws can not go through the 5/8" drywall then the 3/4" stud and the rest of the way through the concrete block.

In the interest of full disclosure I considered myself to be a slightly advanced amateur handy man.. . I have worked as a cabinet maker (granted it was 25 years ago) so I am very comfortable with hand tools and basic power tools etc. but this is way out of line with my experience.

As you can probably tell I am very frustrated. We have been down to one TV for about 10 days already and I am dying to get this new TV mounted and operational but I want to do it properly. Not to mention that the first time I typed all of this in the site ate it so this is my second go at writing all of this out. So any and all help will be appreciated.



Thanks!

Gary

Hi Gary

One suggestion would be to open up a 30" x 15-18" tall hole in the sheetrock and screw pieces of 3/4" plywood into the concrete wall using TAPCON drill bit and screws (see image below). You would also put construction adhesive on the back of the plywood. Then you could patch the wall and tape up the seams or not as the seams would most likely be hidden by the TV/TV mount (up to you) and then install the TV mount using more TAPCON screws. Here, you would drill through the sheetrock and plywood and into the concrete block and then drive the tapcon screws tight! This would guarantee a superior job! Tapcon screws are fantastic at anchoring anything into concrete/concrete blocks. Be sure to measure the thickness of the TV mount bracket, the sheetrock and a minimum of 1" for the block wall to get the correct tapcon screw length.

If your concrete wall is a concrete block wall then another option would be to drill through the concrete and use 3/8" TOGGLE BOLTS (see image). The plywood as noted above would be a great additon to this to keep the sheetrock from flexing, but isn't required. If 3/8" bolts are too large then 1/4" bolts would also work, but I like 3/8" if holes in TV mount are big enough (or can be drilled large). Again, be sure to meaure the TV mount bracket, the sheetrock, the 3/4" space in wall, and then add 3" to overall length to determine toggle bolt length. If you hit a solid rib of the concrete block then you would only need to use the TAPCON screws, but here, I prefer the plywood backer for best result!

Hope that helps!

Mark

I would lag bolt a full size 5/4 x 4 across the wall using sunken lag bolts. I would then lag bolt the mount to the 5/4 board. You can put some nice trim around the edges of the 5/4 and it would look built in.

Thanks guys I appreciate the solutions.. . Both are more work than I would like LOL.
If these were the only two choices I would have to go with the solution ma0641 outlined for a very simple reason. I want to be able to run the wires from the DVR (and possibly a blue ray player or whatever else) on top of the piano into the wall up the 4' to the attic over in between the studs to the TV location and out behind the TV mount in order to hide the wires (I hate visible wires). I do think massplumber's solution seems more sturdy but not being able to easily run hidden wires to the TV is a deal breaker for me. If I had thought of this approach I would have mentioned the importance of being able to run wires in the wall cavity but that approaching never having dawned on me.. . I never thought about mentioning that.

Again thanks for the advice (both of you!) but I really was hoping for a simpler solution :( . In the mean time I have (at my wife's insistence) put the TV on top of the piano so that I do not have to rush into a solution. It is off center and too high by about a foot but at least we have our second TV back LOL.

The bottom line is that I am still looking for a simpler solution if anyone has one. I mean either of these solutions is going to take me the better part of a weekend to implement which is far more time that I envisioned.. . I was hoping for something that was going to take me a hour or two at most LOL. Now that I am not in a rush I am going to wait to see if I can get an easier solution.. . But thanks again guys I really appreciate it!

Well this may not be simpler but this is how I think I would do it.

Put your mounting plate on the wall and mark the points for the screws or bolts.

Drill through the drywall to the cement block with a masonry bit. I'm taking your word that it is cement block and not concrete. Drill a hole in the block large enough for a lead anchor, some times called a lead shield. Install a hanger bolt in the lead anchor long enough to extend beyond the surface of the drywall to accept the mounting bracket, washer and nut.

First question is what size lead anchor. That will depend on the size of the hanger bolt. The size of the hanger bolt will depend on its length. In other words the hanger bolt will have to be long enough to screw well into the anchor in the block and extend out past the surface of the drywall. The smallest diameter hanger bolt that is long enough is the size you will want to use. Then select the size lead anchor based on the size of the anchor bolt. Then drill a hole sized for the anchor.

It will be necessary that you accurately locate the holes in the cement block. Notice that I said cement block not the drywall. So drill the first hole and install an anchor. Now you will be trying to get the anchor in the hole in the block through a hole in the drywall. You may be able to do that with a pair of needle nose pliers. You might put it on the end of small wooden dowel and get it started in the hold. You then use some kind of metal rod to drive it into the hole in the block. An extension bar of a 3/8" socket set would probably make an ideal tool. You then install the hanger bolt. To do that you put two nuts on the machine threaded end of the hanger bolt. You tighten one up against the other so that they are locked together. You use these nuts to screw the hanger bolt in to the lead anchor. You screw the hanger bolt in far enough to ensure that it is well anchored in the lead anchor and extends beyond the surface of the drywall only far enough for you mounting plate, washer and nut.
Remove the nuts. Put you mounting plate on the hanger bolt and position it for drilling the next hold.

After installing the second and subsequent hanger bolt put you mounting plate in place. If you hanger bolts don't come out lined up exactly you can bend them up, down, left or right slightly to line up with the holes in the mounting plate.

After getting all the hanger bolts in place, cut some short pieces of copper pipe, probably 1/2 diameter. These will serve as a spacer between the mounting plate and the block wall. Measure the distance between the block wall and the surface of the drywall. Subtract the thickness of a washer and nut from that measurement. Put the copper spacer on the hanger bolt. Use some paper, caulking, chewing gum, I don't care what, to center the spacer around the hanger bolt. Install a washer large enough to cover the end of the spacer. Probably have to be a fender washer. Install a nut and tighten. That should put some tension on the hanger bolt in the lead anchor and provide resistance to bending of the hanger bolt due to shear weight, although the shear weight is not going to be that great. After tightening it, the nut should be flush with the surface of the drywall. The spacer and nut will also provide resistance to prevent crushing the drywall when you mount the plate.

You have just built yourself stand off's and your TV will be mounted to the block wall and not the drywall.

Patch up the drywall around the hanger bolts. Mount TV. That leaves the wall cavity open for running cable and mounting electrical boxes. With even the most shallow electric box you will probably have to knock out a hole in the block to make the box flush with the surface of the drywall. Common practice when mounting electrical boxes on wall with furring strips (which is what you have, not studs).

Not really difficult to do but you must get the holes in the block close enough that you can make the hanger bolts fit the mounting plate.

Drilling in block can be done with masonry bit, hammer drill and percussion bit would be easier.

You may have to enlarge the holes in the mounting plate to accommodate the hanger bolts that you are forced to use.


Are you done yet?

I did actually think of a solution like that (using stand-offs) but I discounted it as being too weak. I was thinking more like hollow all-thread than 1/2" copper pipe and huge washers though.

I guess the best thing would be to do something like mounting the standoffs with a large plate/washer behind the drywall and a slightly smaller (or larger?) plate/washer on the front of the drywall? Kind of a double sheer thing like they do when mounting a roll bar through the body of a car? My understanding is that if they (the plates and or washers) are both the same size you risk metal fatigue and the metal of the car body (or in this case the drywall) breaking free. But I guess since the main mounting point here is the lead anchor in the concrete block that it is unlikely to happen.

Does that make sense? Either way.. . I really like that idea the best.. . I am not sure if it is substantially quicker than the other methods. But I like it better LOL.

For what it is worth I have to admit that I am less than certain that it is concrete block and not solid concrete.. . But the part of the walls which are not finished (only in the laundry room and furnace/utility room) is clearly concrete block -- but that is along the back of the house and this is along the side so who knows. The house appears to be brick veneer but unusually there are no bricks turned 90 degrees to tie the wythes together where there are obviously two wythes so I guess they used brick ties. The really unusual thing is that the window about 10 feet from the location where I want to mount the TV (in another room) is no where near deep enough to accommodate a 4" thick brick and an 8" thick block and 3/4" furring strips (thanks for that nugget by the way). The point here is that I have no idea until I start drilling if it is really block or solid concrete or what.

Oh and yes I do have a hammer drill (it is a very cheap one and it is a bit slow but on the few occasions when I have had to mount something on the outside of the house it has served me well).

If part is block, all will be block. Probably brick and 4X8X16 block. Concrete would be 8" thick.
You have to anchor in block, drywall not strong enough no matter what kind of anchors you use. Even anchoring in furring strips would not be strong enough. Furring strips are normally nailed to block with cut nails. Great for shear strength but don't have much resistance to pulling straight out. After all they are just metal wedges.
If blocks are concrete no problem with lead anchors as long as the hanger bolts are screwed in far enough to expand them. Might question if blocks are cinder blocks.

If wall does happen to be poured concrete you would use drop in anchors (Red Head) and threaded rod. Still need the spacers to make stand offs. It would be easier to use the threaded rod but drilling accurate holes in concrete would be difficult.

You won't be crushing or bending a 1" long piece of 1/2" copper pipe. You could use 1/2 EMT if you want a stronger metal. Just be harder to cut. If you want to go overboard move up to 3/4".

Otherwise its cut out the drywall and build up with wood and cover with drywall.

Walls probably are masonry walls of block and brick, not brick vernier, if brick vernier you would have studs.

Yeah I hear what you are saying about the brick veneer but every external clue points to brick veneer.. . It was not until I poked a hole in a side wall of the house (to run a LAN cable) that I thought I might even have brick and block construction.. . And until a few days ago.. . I thought it was just along that one wall (the wall with the chimney) and the bottom half of the back wall (with the 12" window sills) because like I said every other window sill is only about 6".. . I am far from an expert in construction (which is probably obvious) but I do not get it. I mean it is pretty clearly brick and block construction except around penetrations through the outside wall which makes no sense to me.. . Part of the confusion might be that this was originally built as a bi-level house (but the original owner bought the house before construction was completed and had the back yard leveled so that the house is a two story slab on grade construction). All of the construction experts I have talked to do not have a good grasp as to why the two wythes were held together with brick ties (assumed) instead of rotating the occasional brick 90 degrees to tie the wythes together.. . But that is neither here nor there.

The blocks very well might be cinder blocks.. . I am not really sure how to tell the difference. I just took another look at the exposed blocks in the washing machine/utility room and they sure look like regular cinder blocks to me.. . I honestly thought concrete block and cinder block were interchangeable terms so I really do not know. There is a small penetration (for a telephone wire.. . Not done by me) in the utility room going into what was originally the garage (which the original owner had bricked in and made into an extra room.. . A decision that I curse after every snow storm) and trying to look through it.. . It sure looks like cinder block to me.. . Either way it is hollow block with about 1" thick walls as near as I can tell.

You seem to have indicated that a different approach needs to be taken with cinder block as opposed to concrete block what is that different approach?

Oh and for the record how does one tell the difference between concrete block and cinder block?

As far as the plates . . . I understand your point I will not use them. In all honesty I will probably use 3/4" copper pipe.. . But only because I have some of that lying around the house after I used it to make a pole for a bird feeder (the readily available poles did not mount the feeder high enough to see the feeder when sitting down and looking out of second floor window LOL).

Thanks again for all of the advice Harold I really appreciate it.

Gary

Well I looked up the difference between cinder block and concrete block.. . And it is more than a bit tricky to tell the difference. The general rule of thumb seems to be when was the house built? If it was built pre 1960.. . You probably have cinder block.. . If it was built in the 1960's it could be cinder block or concrete block after 1970 or so and it is almost certainly concrete block.

What is the difference you might ask.. . Well Google it if you want a definitive answer.. . But the gist of it is that cinder block is light weight weaker concrete block in which the primary aggregate is cinder (the remnants of coal which used to be commonly used to heat homes) where as concrete block is heavier stronger concrete block in which the primary aggregate is something other than cinder.

The primary difference is the weight of the block.. . Which is impossible to ascertain in a built house without physically removing a block. So you have to look to other methods to figure it out.

Now in my case my house was built in 1967 in a middle class suburb of Washington DC so the odds are that the house is built with concrete block. As I understand it the only way to definitively say if the house is concrete or cinder block would be to send a piece of block off for chemical analysis. If this was a cheaply built house in 1967 it is still possible that cinder block was used.

So that being said unless Harold (or someone else) comes back and tells me otherwise.. . I am assuming that I have concrete block and I will moving forward with his suggestion in the next few days.

Thanks again to all who answered and helped!

Odds are concrete. Purchase a concrete block. Punch or drill a hole in it.
Then punch or drill a hole in what you have. If it takes equal effort then you have cement blocks. With experience you could probably tell the difference by just looking at them, certainly by picking one up.

I have a few concrete blocks I purchased about 3 or so years ago that are holding up a firewood rack I made off the ground outside.. . I can easily punch a hole in one of those as a comparison.