Looks like MDF. If it will still be covered by the tv, I’d just use spackle.

My child has learned that you can fill wood holes just as easily as car holes with bondo all purpose putty. It sands well, and takes paint. And it's far better than wood filler. I haven't tried it, so if you want me to ask them questions I can.

https://www.theweathereddoor.com/2017/10/furniture-repairs-bondo-vs-wood-filler.html

Are you saying that you want to fill up the holes so that you can reuse the same holes for the new mount? If not, I'd just use caulk to fill in those holes. Also, to put up a new mount to hold up right then finding the studs in the wall for the new screws is the best support. One main stud should be either to the left or right of the electrical outlet which is most likely attached to a stud. Typical studs are about 15" apart.

Are Canadian building standards the same as in the USA?

" Are Canadian building standards the same as in the USA? "

I have no idea.

Carol just means that your width may not be 15 inches away from the outlet. That's all.

MDF isn't exactly wood. I'd stick with Spackle or its equivalent/something similar.

The distance between centres of studs in a room in my basement is 16 inches.

ole joyful

Better get rid of that woodpecker or it will only make more holes.

I wouldn't think that the electrical outlet is up to code whether you are in Canada or the USA. Is the electrical outlet inside or outside? If it is outside, it wouldn't pass Michigan code.

" Is the electrical outlet inside or outside? "

Oh, this is an inside wall. I realize now there was no context, but it's not outside. That's just the wall decor the previous owners chose, and I kinda like it.

Use an epoxy wood filler. There are several kinds. I always have used one that is a dry powder that you mix with a liquid to the consistency you want but there are premixed as well. It will stick better. Spackle is designed to stick to drywall. Ask at the hardware store. I expect there is a stud between the outlet and the box with the cable connectors. measure from there. Also anywhere you don't have a stud use good large anchor screws-for choice the toggle kind. TV's are much larger and heavier these days.

Looks like a particle board of some flavor. Do you need to reuse the same holes with screws?

tj

I like Plastic Wood. Push all the edges inside first, then fill. It is sandable.

Looking again at the ele outlet and the 3 biggest holes in the wall it looks like the stud may be on the left side of the ele outlet. You can easily determine this if you remove the ele outlet cover* and see which side the interior nails are attaching the outlet box to the stud. Those 3 largest holes are most likely lined up with and drilled into the stud to support the weight of the tv mount. The cable box probably does not need any real support so may not be stud attached.

* Turn off that circuit breaker first of course.

It's hardboard paneling coated with acrylic paint It's a wood so a wood filer will kinda work but won't look good. Edges of the hole won't sand smooth and will break loose when trying to sand unless the hole edges are reamed to remove the loose material.

Referring back to Rob333's post Bondo (or similar) will work much better than wood filler but will shrink and crack in holes that big so two applications will be needed, and the hole edges still need to be reamed.

@always_beezee - Curious what in the pic suggests the outlets are not to code? I mean, obv if outside but it’s not and your comment doesn’t sound dependent on that.

Not sure how to best repair the fiber panels. I think it’ll be hard to make perfect and durable, so best to plan on mounting a TV such that it best conceals them.

What about the spacking used to fill sheetrock holes?

Bondo or M&H Ready Patch would be my choice.

Being lazy I'd still use a tube of white caulk to fill in those holes. It's quick and easy and if dimples form they can be re-caulked and smoothed out with a wet finger. Home improvement stores have caulk in different shades of white to best match the original color so no painting required. First though I'd shave/level off the raised rims around the holes.

Forgot about caulking!

Bondo or M&H Ready Patch would take paint and look like a finished wall as opposed to caulk.