Home built in the 60's, exterior brick, block basement. Walls uninsulated.

What will I hit if I attempt to install a low voltage box in an exterior wall and drill through the bottom 2 x 4 (I would assume).

1) Will I hit basement?

2) Will I hit somewhere in the top of a block in the basement?

What is more likely, 1 or 2?

A block basement on a ranch house, You know concrete blocks are hollow inside so you can measure from a corner to figure out wher the hollow coresa are. A foundation wall usually has rebar inside some of the blocks and those cores would be filled with cement around the rebar. This is usually a foot in from each corner and then every 4 ft or 8 ft along the length of the wall. So those would be troublesome areas. On the top of the last couse would be the foundation sill that the floor joists are nailed to usually it's a double 2x4 laid flat. The sill is also held to the blocks by anchor bolts cemented into the cores of the blocks probably the same areas previously mentioned. For a brick home there would be a double wall of bricks with an empty void space inside or it could be brick veneer with only a single layer on the outside which is attached directly to the wood framing with clips cemented into the mortar between the bricks and no hollow space inside the wall.

I believe that you will drill into the floor joist space. The floor is probably 2 by 10s (or even 2 by 8s) about 16 inches apart. These floor joists would rest on top of the block wall. One difficulty would be if you came down directly into a joist - if this happens, simply drill another hole 1 1/2 inches to the side. A second possibility would happen if the wall you are working in runs parallel to the floor joists and the last joist space is less than the thickness of the basement wall. In this case, you may have to cut a hole through that floor joist to get the wire through.

david:

I think your right. The 2 x 10 floor joists will be perpendicular to the wall.

I just remembered that on the opposite side of the house there is a surface telephone jack run with a hole in the floor at the baseboard moulding. The hole is 4" from the inside edge of a 2x10. The moulding and 1/4 round make up 1.5", so I have 2.5" left assuming 1/2" drywall.

So, if I drill 1.25" from the inside of the drywall, I should be where I need to be.

I can detect where the floor joists run with my Stanley stud finder and also do the walls too.

Good job!

I'm planning one, possibly two 1" holes drilled through a double gang low voltage box opening with a flex bit and steering wheel.

David will be correct 50% of the time. If you check your basement so if the joists run paralelle or perpendicular to the wall you are drilling in. If they are parallel you may hit a double ax10 almost everywhere you drill. I usually pop the baseboards and drill a 1/4" test hole on a slight angle into the cavity, my helper than holds a flashlight on the hole and I go into the basement looking for my beam. Sometimes it's there and sometimes not. The nice thing about baseboard test holes is you can drill hundreds and only you will know.

The floor joists are perpendicular. Perpendicular looks like the better wall.

What my father did was to drill a small hole (1/16") at the edge of the baseboard and then drop a wire down and go look and then patch the hole. Easier to spot.

Thanks.

PS: I'm painting and all sorts of other stuff. That's a bed room with a twin lead antenna and 4 prong jack. Time to upgrade. I probably won't wire until I have to. I'm also installing tamper proof outlets. (2 prong to 3 prong tamper-proof). The BR is unoccupied.

I want to eventually go to home-run telephone, but I'm not there yet.

Does anybody make an "old work low voltage dual gang mounting frame with a conduit hub"?

KISS, you better ask that in a separate question cause maybe people won't read all the answers? I know you can go through a wall or through a floor joist pretty much anyway you want but if you go through a floor in a building you need to protect that part by enclosing it in a piece of metal or rigid conduit? Because of bending stresses on the floor from loads in the room, floorboards swelling and shrinking due to humidity, people putting floorcovering or carpets on floor, furniture bumping up against walls... that could possibly pinch your wires or cause them to be damaged?

wind and blue: I'm drilling through the 2 x 4 BEHIND the drywall through an approximate 4" x 4" (dual gang outlet box) opening in the drywall to the basement below.

The surface mounted telco jack present in another room is 3/4" from the floor. You can't protect that much more. The carpet makes the bottom of the box about 1/4" away from the rug.

I guess I did misunderstand. In your original post I thought since you talked about an exterior wall you were on the outside of the home wanting to feed wire into the basement so I was trying to say how or where to simply drill through the foundation block wall to access the basement. And my advice about the metal pipe, it simply has to do with fire code if you are drilling/feeding wires through a floor. If you are going through a wall the wall already has fireblocks etc to prevent the spread of fire through the wall plus the drywall covering that will not burn. So no pipe is needed.

I guess you have never seen products such as these?

Tools: Drill Bits

The bits need to be used with the steering guide.

Got both holes drilled. I could not see down through the dual gang opening even with a mirror, so I got it as tight against the wall as I could. The edge of the 1" hole is within 1/2" of the floor 2 x 10 that rests on the cinderblock and runs parallel to the wall.

The wall studs were directly on top of the floor joists.

I needed a freshly charged battery for my cordless drill to make the holes. A 1" hole is difficult for a 9.6V Makita drill to manage.

Pulled the pulling string through too.

Thanks.