Ceiling fixture: replace knob & tube w/ Romex...

[speede541]

I've got two ceiling fixtures wired with knob and tube wiring, and I'd like to update it with Romex.

The walls are open in both off these rooms (repairing damage after a foundation project). So this is the opportune time to get at these two fixtures.

Problem is, the lath & plaster ceilings in both of these rooms is intact, so I'd like to avoid hacking into them, if possible.

Oh, and these two rooms on on the second floor of a three story house, so there's no easy access to the fixtures from above.

Any hints, tips or tricks for simplifying this procedure? Is it possible to use the old wire to pull the new Romex? I really have no idea how to go about this.

[badeyeben]

Most of the knob and tube I have seen is a single wire ran thru a tube placed in a hole drilled through the ceiling or floor joists. The hole is not large enough to get romex through.
You may be able to change the direction of the wiring by going between the joists in the open space. Use a fish tape to go up through the top plates of the wall and to the lights then drill the wall studs to get the wire to the power box.
Just cut back and abandon the old wiring in the ceiling.

[ray2047]

Is the third floor carpeted? If it is and does not have floors you might some day use without carpet there is another way. Just roll back the carpet and remove just enough flooring to do the work then patch and replace the carpet.

[speede541]

Originally Posted by ray2047

Is the third floor carpeted?

No, unfortuantely (fortunately) it's all wood floor -- not anything I can easily pull up.

With the light at the entry, in line with bad eye's suggestion, it looks like the joists are running towards the wall I've opened up. So it should be easy to fish some new Romex in.

With the light in the dining room, I haven't opened that wall yet, but I suspect the joists are going to be running towards a wall I don't need to open.

Our contractor (working on a different area of the house) suggested leaving the knob and tube in place after the light switch. I'd just as soon not. It's just that I'm not looking forward to opening up a perfectly good ceiling when I have so much other work on my to-do list!

[ray2047]

You don't have to open the whole ceiling to run perpendicular. Either buy or borrow a right angle drill or buy a right angle adapter for your drill. Determine the location of each joist. First is hardest after that uniform spacing should tell where the next one is. Now make a hole just large enough for the right angle drill on one side of the joist and dill a 3/4" hole in the joist at least 2" up from the ceiling.. You should only need to make 3 or 4 holes for an average size room. (There needs to be only one per joist.)

Tip: use a short shank spade bit just long enough to go through to keep hole size in ceiling as small as possible. If no short shank spade bit available use a hole saw that drills deep enough to go through joist.

[speede541]

Here's where it gets whacky.

We did some exploring yesterday and it turns out one of the ceilings is a double ceiling. Story goes that there was once a fire in the room upstairs, so the visible drywall ceiling is probably hiding the damaged lath & plaster ceiling.

The drywall ceiling is attached via strips of 1x2s, which, unfortunately, are running perpendicular to the direction most convenient for me.

I assume the 1x2s are attached through the plaster to the joists above.

Anyhow... at least I know which way I need to go in.