Hi all
I have a 75" TV that I want to mount above a wood burning fireplace (don't worry, the fireplace is not in use!) in a 1920s built house. I have bought this pulldown mount from Monoprice (https://www.monoprice.com/product?p_id=27773). The weight of the TV is 79lbs and the mount itself is about 33lbs.
The wall is plaster and wood lath with brick behind. The brick is about 2.5in behind the face of the wall (plaster and lath about 1.75in and 0.75in gap).
Since the wall bracket for the mount is I-shaped (i.e. bolted across the top and bottom, I'm thinking to cut out two parallel channels in the plaster the width of the mount to expose the brick, fasten 2x3 lumber using anchors into the brick so it is flush with the wall, then attach the mount to the 2x3 using lag bolts as if they are studs.
Requesting feedback or other suggestions. Hoping to limit intrusion into the plaster or face my wife's wrath. Thanks

 

There must be studs back there too between the lath and the brick.

Your idea of mounting lumber directly to the brick could be sound.
You wouldn't be using 2x3's. Too easy to split. More like 2x6's.
The two wall brackets should be 14"+ apart.
You'd need to determine the condition of the brick to see if the 2x can be securely fastened to it.

 

Yes I assume there is 1x2 or similar between the lath and the brick, hence the 0.75in gap.

I was thinking 2x3 because placed on it's narrow side it would be almost flush with the finished wall (same orientation as a regular stud). You think there is a risk of it splitting when screwing lag bolts into the narrow face?

Any other problems you think I might be overlooking? I'm concerned about the ability of this setup to withstand the load given that it's such a heavy TV extending outward from the wall when the mount is pulled down.

 

I started taking out some plaster by tracing along one of the lath strips. How do I determine the condition of the brick? I don't know if this looks good or not.
Also there are very mixed views on whether sleeve anchors should be placed in the mortar or center of the brick. How to decide?
Thanks

 

There is no way to really know about the condition other than a good eyes on inspection.

Drilling into brick can be touch, if they are fired or dried the strength/hardness can vary. Your instructions dont cover brick mounting but they do state not to mount into mortar for blocks.

Normally mounting a TV of that size/weight would be a piece of cake till I saw how far out it articulates, thats a lot of mass hanging out there with a questionable mounting surface.

 

Interesting. If the brick are soft enough to drill into will they hold the anchor? If they are too hard to drill then go for the horizontal mortar joint. You should get a feel for how solid it is when you drill the holes. I would use extra bolts to help make sure. And even though it is doubtful if it would help clean the brick well and use some liquid nails liberally. This is a belt and suspenders thing. If I could think of anything else to help hold the assembly I would suggest you do that too. People who know more about this than I might tell you to epoxy in the anchors. From this distance the brick and mortar look sound. If it is Portland cement mortar it is probably harder and stronger than lime mortar.

 

I'll tell you how I'd do it. I'd attach the two) 2x's on the brick. I'd use expansion sleeves into the brick.
After mounting the 2x's to the wall....... I'd cut a piece of 3/4" plywood maybe 4" bigger on all four sides than the cut opening. Screw the board into the lath. The lath itself has a lot of inherent strength with the plaster. The combination of the plywood and the 2x's on the brick should be strong enough.

The larger the plywood..... the more strength it will add to the installation.

 

Might be a good idea to try a test anchor before proceeding.

 

Do you have access to the other side of the brick wall?

 

No, this is above the fireplace, so I assume just the flue behind it. No idea how thick the wall is before you hit the flue lining.

 

Pjmax has a good idea. You know where a lath is the lath are spaced 1/4" -1/2" The lath are 1 1/2" wide. you want to hit the meat of the lath. If you hit the key, the space between, you will know it. Also if you can find the furring strips, whatever they be, behind the lath you will get some good bearing for your plywood. Don't use screws so long that they hit the brick before they draw up the plywood.

Anchors, screws into the lath or furring or both through plywood, construction adhesive. Let it all cure then hang on it. Will it hold you? Then it will probably hold the TV

 

Personally, I think I would give that non articulating mount some consideration, The weight is not that great but when you hang it out by 12" (or what ever that thing can do) the shear forces increase, the limit is the weakest point in the installation!

Call the manufacturer, see what they think and let us know!