Careful Rewiring Techniques

To replace the older existing wiring in your house, whether it’s knob and tube wiring, BX wiring, ungrounded romex or aluminum wiring, some holes will have to be made in your plastered walls / ceilings to fish the new wiring around. Yes that’s right, unfortunately there is no way around this fact. But don’t fret, it’s not all bad news!

If your home has an unfinished basement (Basement with open ceiling joists, NO ceiling), all the outlets and switches on the floor above are accessible from the unfinished basement. Meaning most of these items can be rewired with little to no damage.

Lights on the other hand will require some small holes to fish the wiring from switches to the lights which I’ll explain more later.

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Above, This is a good photo of an unfinished basement. Unfinished means no drywall or plaster on the ceiling or walls. The joists can be seen clearly and the wiring within. We ask homeowners this on the phone all the time, and a lot will say it’s unfinished, but when we get there it’s a finished ceiling.

If you have an unfinished attic, even better! EVERYTHING below this floor will be accessible from the attic space. We would be using this attic space to fish new wiring to all the lights, outlets and switches.


The picture on the left is an example of an unfinished attic, with quite a bit of knob and tube wiring run about. When there is an unfinished attic, electricians can pull insulation away and drill down into the walls below. Avoiding holes in the finished plastered walls and ceilings on the floor below.

The most difficult floors to do are ones that are sandwiched between two finished floors (think 2nd floor of a three family house). These floors have NO unfinished spaces above or below, so holes will be needed to fish wiring to all the lights, outlets and switches.

Now you may be asking, well how big are these darn holes? Great question! We are normally using a 1” drill bit, But as you may realize, older plaster and lat walls tend to fall apart a bit when drilled into. Sometimes the holes can become a bit bigger than 1”, maybe 1.5’s or so, usually no larger than that.

Below are two good examples of what kind of holes it takes to fish wiring from a switch to a light on a floor that DOES NOT have an unfinished attic above –

The picture above illustrates the holes needed to transition from wall to ceiling quite well. One other thing you may notice is the patching around the switch box. When we remove the old box, sometimes the plaster falls apart around it and needs to be patched in. This is really dependent on the condition of the plastered wall.

The above picture shows the route we took from the switch box to the light. One hole on the wall (behind wall paper), one hole on the ceiling right above, then one more hole inline with the light.

This allows us to fish the wiring from the switch box to the light. You may notice the other hole we made near the switch box. This was due to the cellar below not extending far enough to fish up directly below the switch box. We had to come up in the bay next to it, then drill through one stud to get into the switch box location.

Additional Headaches fishing wiring

There’s a few more issues that can come along to spoil the day, even on first floors. If your home has a lot of chair rails, there can often be a horizontal piece of wood spanning the wall studs at the height of the chair rail. Sometimes you can sneak the snake / wire around it, more often than not a hole or two are needed to drill through it.

  • Wind braces – these are really common in older homes. It’s a piece of wood in every outside corner of a house, running diagonally between the wall studs. These braces will be impossible to fish through, and will require notching or drilling holes in the wall.
  • Random blockings- Lots of older homes, especially those built pre 1880, will have random pieces of wood in walls and ceiling, for seemingly no reason at all. It’s almost as if the builder at the time had an extra few pieces of wood and said, “oh just put them in the wall!”. A home we rewired in Marblehead was built in 1760s, and boy was this a tough one. First off, every wall is extra thin, requiring special boxes. On top of that there was random blockings EVERYWHERE. Fishing across a dining room ceiling about 10’, which is normally VERY EASY, would take 4+ hours in this home. We learned a lot about these 1700’s era homes during that job, or I should say we learned how to properly estimate/price these ones, cause they take twice as long!!

Have wallpapered walls?

Wall paper can pose some issues, as mentioned earlier some holes need to be made to fish the new wiring. Depending on the condition of the wall paper, it can often be sliced, peeled away from the wall, then glued back. If the wall paper won’t peel, it typically rips. Take a look at the photos that follow for an example, and try not to pass judgement on the wall paper design!


We have worked in many homes with wall paper, and have had really good luck slicing it and peeling it back, then gluing it back in place. If enough care is taken this can be done and you may never even notice the wall paper was disturbed!

Disclaimer: On occasion the wall paper will not peel off the wall and rips!


We really love to get creative and find new and different ways to accomplish rewiring jobs with as little holes as possible. If you are concerned with what it will take to rewire your house, please give us a call today. We’d be happy to come out and educate you as to what it will take.

We never back down from a difficult house, we look forward to the challenge!