They make superglue in thin viscosity that will penetrate cracks (frequently used in woodworking). You might be able to use that, clean off the excess, then spray the hardener. For any approach the concern is impurities in the crack like soap scum and oils.

You need to put insulation in the ceiling. Any other attempts to insulate without insulation above is futile since the majority of heat is going to be lost up there.

I would just hire a company to come out an blow insulation up there. I just had my one car garage done for $650 and they had to build an air vent along the soffit on one side. It was really worth the pros doing it and me not having to take hours or days to learn how to lay insulation properly on exterior walls.

In Cali I'm sure its probably pricier but when I priced it out to pay someone to do it was about as much as it would be for me to buy materials.

At worst they get a very minor shock… while electricity is dangerous it is very very hard to seriously injure yourself messing with the wires at this point. Only if you both have a serious heart condition and touch it in such a way that caused that electricity to travel past your heart just right. Both not likely.

Redditors get too fixated on safety rather than help solve the problem. It’s r/DIY not ‘r/callaprofessional’

If you’re that concerned for safety, educate on what they need to do to protect themselves rather than just say call a professional. Defeats the whole purpose of the sub.

Pretty sure Clay liners are set in mortar. Saw a chimney company jack hammer one out for about 2 days. I'd definitely hire someone to do this.

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You will never find a concrete slab that doesn't have cracks.

The problem is when they get large and have height differences.

Absolutely zero structural posts should be removed. Only non structural should be removed.

I worked in new builds, and you would be surprised how much cracking is considered normal. One year in, and crack that goes up halfway up the apartment? Eh, just building settling, put some filler on the crack and go about your day.

Have a structural engineer evaluate. If you just don't want to go the proper route. If that is a beam that it is holding up then it is load bearing. You need to know the type and size of beam and what distance it can span without support. Also if there is livable space above this then that changes calculations because of the live and dead loads that beam must support.

I should've stressed that I have zero DIY skills or experience so for me Captain Obvious is a helpful instructor.

“One wire is live and the other becomes live when the switch is turned on” this person doesn’t understand basic current flow. Not everyone should do home repairs.

I'm pretty sure if you keep filling the cracks the slab will eventually expand to encompass the entire neighborhood.

I'm assuming you don't do wood either, or any substrate then?

How do you tell if it’s structural?

Lmao. If they are structural you can't remove them unless you design a way to redistribute the loads they carry. There isn't somewhat structural. They are either load bearing or they are not.

What? This is a simple home repair. Damn, people these days are so happy to be incapable.

I ended up using Devcon epoxy/fiberglass repair and it came out awful! Gonna try wet sanding around the sides when it dries.

https://imgur.com/a/9L90X4d

Definitely do that

Gonna sound like captain obvious but anti split wood screws, slower the insertion the better, sometimes unfortunately it's unavoidable. You can use wood filler to clean up the cracks.

You know you can't bomb cracked walls to find secrets in real life, right?

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Think at least some sandpaper can help you clear the worst of the debris - it will look nicer in the end

I had this exact issue and couldn’t work out why my light wouldn’t work, it was the living room light and it turned out the kitchen wiring wasn’t correct so electric wasn’t “flowing” into the living room.

OP check the wiring of your other lights on the same floor

It may be cheaper and easier to replace it with something similar. You could also get some sandpaper and some of the bathtub enamel touch up paint and use that to touch up the areas.