Mounting TV through HardiePlank siding

murpbrad · Jul 13, 2023

I'm looking to mount a TV outside on our back porch. Hardie Plank siding over OSB. This particular wall has no windows or anything else to measure studs off of, so I'm unable to know for sure from the outside. The TV mount I want to use only uses two lag bolts to attach to the house (see photo), so it obviously would be best to be in a stud. Without the certainty of finding a stud through the layers of Hardie Plank and OSB, what would be my best options for this type of mount? TV mount has lag bolts 6.5" apart. Hardie Plank siding is 7' wide, so runs a pretty high risk of fracturing it close to the edges.

1) Should I mount a 2x10, 2x12, etc directly onto the siding, and anchor it to the OSB if I'm unable to find the studs for certain, then mount the TV mount to the 2x10?

2) Should I mount the TV mount directly through the siding into the OSB? Will that provide enough strength? TV is only 13lbs, so nothing crazy heavy, but it is only spread between 2 vertical screws instead of 4 on the corners like some of the larger TV mounts. This would have the TV mount slanted at a slight angle upward due to the slope of the siding.

3) Should I cut away a portion of the Hardie Plank siding the size of the TV mount where I think a stud should be? This would have the TV mount installed flush with the OSB. If I don't have a stud, I can at least go directly into the OSB.

4) Should I do something completely different? Using a different TV mount is my last option. We need the motion that this one provides, if at all possible.

Thanks in advance

A Little Short · Jul 13, 2023

Get a stud finder with deep scan capabilities. I said 2x6 but I just meant whatever size you need to fit the mount.

Alternately, you could use toggle bolts to install the mount.

murpbrad · Jul 13, 2023

Sounds like getting a new studfinder is going to be the best option. Was hoping to not have to put a 2x10 over portions of two pieces of siding since it may look odd, but that may be the only option.

As far as toggle bolts - just through the OSB, right? I still worry about the pressure of the mount breaking the cement fiber siding once I tighten it down, regardless of what it anchors to.

HotRodx10 · Jul 13, 2023

If there's a window or door nearby in the wall, you can find the studs on the inside, and with a little careful measuring, you can figure out where they are on the outside.

murpbrad · Jul 13, 2023

Thanks. No windows or doors. No outlets or light switches. Just about 5' of wall.

A Little Short · Jul 13, 2023

Use a stud finder to find a stud. If the stud isn't where you want it then install a 2x6 to cover two studs, then mount the TV to the 2x.

murpbrad · Jul 13, 2023

Sounds easy enough, but my studfinder is not finding the studs through the Hardie Plank and OSB. And a 2x6 isn't going to be wide enough for the TV mount. A 2x8 (actual width clower to 7.25") isn't really quite wide enough, so a 2x10 would be about the smallest I could use. That would overlap 2 pieces of siding, so still not ideal.

chandler48 · Jul 13, 2023

Look for nails in the Hardie Plank. Generally they will be over a stud, not always. Drill holes with a concrete bit and put them in the middle of the planks. There may be a gap at the top and bottom due to the lap of the planks, just don't pull the screws absolutely tight.

murpbrad · Jul 13, 2023

No sign of nails in the Hardie Plank without lifting up the bottom of a piece to see the top of the piece underneath, unfortunately. Plus, based on another wall where I put in a doggy door, I found that the Hardie Planks are just nailed into the OSB in most places, and not into a stud at all.

murpbrad · Jul 13, 2023

Is the OSB strong enough to hold the TV with just 2 wood screws? Should be fine, right?

HotRodx10 · Jul 13, 2023

Maybe; maybe not. Because of how far out from the wall it could be, the 13 lb TV plus the 5 lb mount can produce 80 lbs or more tension force on the top mounting screw. 7/16" OSB may or may not hold that.

Biscuits · Jul 13, 2023

If your backporch is big enough to lounge on and watch TV, maybe just get a small piece of furniture the TV sits on.

Mounting TV through HardiePlank siding

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