Submitted by SluggoJones t3_z3679y in DIY

Trying to wire Ethernet & cable through the basement and up into the wall cavity (interior wall) in family room. For some reason, all the electric on the first floor is wired up (towards the ceiling) instead of down and through the basement so I can’t just feed cables through an existing hole. As I started to drill up through floor from basement, saw dust changed to grey dust and I stopped. What the hell is the grey stuff?

Context: 1. I was using a spade bit but switched to a regular drill bit to see if I could punch through (which is why you see a 1 1/4” hole and 2, 1/2” holes). 2. House was built in 1968 and is in New England. 3. I’m stupid. 4. Refer to #3.

Edit: So if Im running into the tile, my normal next step would be to drill another hold further over hoping to come up inside the wall cavity… but the previous owners built a cough semi cough finished room on the other side & seemed to add a bunch of wood to make it (I updated pic folder to show). You’ll also see I broke through the dry wall in the “semi” finished room in the basement to access underneath what I thought was the wall cavity only to resize it was easier to access from the other side, where I removed and old cabinet the had mounted for storage.

Edit 2: Thank you everyone for your advice. There are some really smart people here and I really, really appreciate you taking the time to share your wisdom/saving me. Thanks. I’ll try to post some pics when it’s done.



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AlfaBetaZulu t1_ixkcscd wrote

Looks like cement board. Also just a tip but you should drill from the top down. Especially with that hole saw you're using. If you do come through the hardwood it's gonna blow out if you come from underneath.


bridaddy t1_ixka7eb wrote

Drill a small hole ⅛ inch or smaller (just big enough to slide a single thin wire) in the hardwood right up against the base board. Measure about 2-2½ inches towards the wall you're trying to get into. After your done fill the small hole in the hardwoods with putty.


crit1calends t1_ixkoa3y wrote

So, I do this pretty often for work. With practice it takes ~5 minutes for a professional looking job.

First, I cut a hole in wall where the cable will come into the room: it needs to be just the right size and shape to hold a "low voltage mounting bracket." Watch for live wires in the wall.

Next, I feed a "flexible installer drill bit" of appropriate size into the hole and drill down, usually into a crawlspace. Make sure there are no live wires in the hole to hit with your bit.

(Some bits have a small hole to tie to, so you use it to pull your wire back up. However, this never works as smoothly as you'd hope. Instead, you can....)

Feed a couple feet of your cable up through the bottom, then upstairs you can just reach into the hole you cut and pull out your wire. Don't go sticking your hand into random holes without checking first: watch for live wires.

Slap that low voltage mounting bracket in place and install the wall plate of choice.


StuckInTheTimeVortex t1_ixl2mem wrote

I'm getting the impression I should always watch out for live wires.


summercampcounselor t1_ixk6ozc wrote

I’m no expert but nobody has guessed yet so I’ll take a stab. Leveling concrete?


MovingMadness58 t1_ixkk996 wrote

Just a heads up never run Ethernet wire (Cat5e,Cat6 etc..) through the same hole that electrical wire runs through, running Data wire parallel to high voltage wiring will cause interference and could lower speeds. Running a wire across or perpendicular to high voltage is OK though. I’m a low voltage tech. Also if you are doing a lot of drops in you house invest in one of these


blimpcitybbq t1_ixkksaa wrote

pull off the toe molding then drill a tiny hole or drive a thin nail down through. then you'll know where you are and can adjust accordingly. Then replace the molding and it will cover it all up.


loganab13 t1_ixk6mwu wrote

What is the floor up above? Almost looks like tile backer and thinset


SluggoJones OP t1_ixk7pp4 wrote

Hardwood floor on one side of the wall, tile on the other. I updated the Imgur link with a couple extra pics.

Please, please, please forgive the awful quarter round the previous owner put around the door trim, the weird ass floor transition & blue tile from the 90s. We just moved in a couple months ago.


loganab13 t1_ixk870y wrote

I don’t know which side of the wall you’re drilling on, but you’re likely running into the cement tile board and thinset layer. If it’s on the other (hardwood) side of the wall, it could be self leveling compound.


stinger_ t1_ixke5py wrote

You guys get much asbestos tile in your area?


loganab13 t1_ixkebbr wrote

Yeah, I’ve run across a good amount in my commercial construction career around the Midwest. Funnily enough I just ran into some in my own bathroom remodel this past weekend.


DotAccomplished5484 t1_ixkq268 wrote

Not a concern here. Cement backerboard was introduced in the 1980's, well past the asbestos days.


trashyratchet t1_ixklai9 wrote

Flex bit and placement tool is what you need to drill down into the wall. You're going to have a huge mess if you break that tile floor.

Although, I would cut a couple of feet off of this linked flex bit shaft to make it more manageable to work with. Its the first hit I got in google. My bit is about 3 ft.

Cut your old work low voltage bracket hole in the wall and install the bracket, then use this kit to drill down. The placement tool easily bends the bit to hit the middle of the sill plate.

I've fished hundreds of low voltage outlets in my career and currently train technicians to do this every month. Trust me, this is the way to fish an outlet down to a basement or crawl.

And as a side note, the person that warned about running comms in close proximity and parallel to power is absolutely right. That can possibly cause some induction issues, aside from accidentally getting into your power insulation with your tools, and should be avoided. You want to keep some space between them.


ApplicationEast78 t1_ixk75l8 wrote

Is there tile above it are any flooring?


SluggoJones OP t1_ixk80m0 wrote

Yes, there is tile in the bathroom which is on the other side of the wall from the family room. I updated the pic link to show the wall cavity I’m trying to run the cables up into.


ApplicationEast78 t1_ixk8m3n wrote

It’s the tile I bet you can get a tile bit at the store and drill threw it I normally drill from above down, but be careful if you use the whole saw bit it’ll catch bad when you get threw and twist your wrist. You do risk cracking the tile doing it from the back side just a heads up.


therealmattsteimel t1_ixkbkn1 wrote

Get a wire hanger. Cut the straight piece out of it. Put it in your drill and place it right next to the wall and drill down into the basement. The hole it leaves is not noticeable abs you can easily figure out how everything lines up.


kynthrus t1_ixkh8qc wrote

That's cement.


One_Car_142 t1_ixkpg8v wrote

Does your house have plaster walls? When they squish the plaster against the lath some usually drips down and makes a pile at the bottom of the stud bay. I recently renovated my bathroom and found every stud bay had 1-2" of plaster piled up in the bottom.


theo2112 t1_ixm6hne wrote

An aside, you should never run data cables parallel (through the same hole) as power. You’re power cables will interfere with the data and reduce performance.


lordicarus t1_ixkaqs7 wrote

Is your goal to have the wire come through the tile floor? Because that's probably what's going to happen if you continue drilling. Are you sure you measured correctly?


kittenrice t1_ixkw97u wrote

You are not drilling where you think you're drilling.

As you now know, that's tile backer/cement board, which is underneath the tiles in your picture.

I mean, maybe your goal is to run cat 6 up through the middle of the floor, idk, I prefer it being in the the wall myself. Or maybe the 'target' wall was built on top of the tile? Crazier things have happened.

You need to make some sanity checks here and measure out where to drill 3 or 4 more times. Or open the wall where you want the wires and drill down.


SluggoJones OP t1_ixmf4lx wrote

Thank you everyone for your advice. There are some really smart people here and I really, really appreciate you taking the time to share your wisdom/saving me. Thanks. I’ll try to post some pics when it’s done.