Keys To A Successful Knob & Tube Job
** originally posted on Linkedin Mar 22/17
I often hear from people that electricians don’t like knob and tube (K&T) rewires. No question it is a challenge, can be messy and you never know what you might find when you embark on a K&T job. Call me crazy but I enjoy the challenge of completing a whole house K&T rewire. It is the ultimate test for an electrician to complete this job on budget with minimal damage to walls and minimal disruption to the customer while you are there.
When I started my career as an electrician I worked for a company that specialized in K&T rewires. Most of these jobs took place in old 100 year old or more 3 storey homes located in downtown Toronto. The foreman on most of these jobs was a young guy named Rico and I learned a tremendous amount from him about K&T rewires and residential electrical renovations in general. I called him the “Bassmaster” because he could fish a wire in any wall or ceiling with minimal damage. Many of the homes we worked in had ornate crown moldings and textured finishes on the walls or ceilings and we had to fish around these obstacles. Like any good angler you have to have patience and be willing to try different lures to catch the big one.
So what are the keys to successful K&T rewire? How do we define success? The job is done on time and on budget with both the customer and contractor being satisfied with the results. Here is what I believe helps meet these objectives.
Minimize the Damage
I hear stories of electricians using their hammer to punch holes in walls to make it easier to fish a wire from one point to another or install a new box. Personally I have not seen this performed but I have heard the story from several different electricians so maybe it is true. When you do a K&T rewire you need to make holes in the walls in ceilings to allow you to install the new wiring. It would be nice if you could avoid this but as Scotty use to say to Captain Kirk…..” …captain, I’m an engineer, not a miracle worker!”. That being said their are more civilized ways to make the wall and ceiling penetrations
When we complete a K&T rewire we use a 4” hole saw to make hole (not a hammer). Why 4 inch? The 4” hole is big enough to allow us to put our hands and sometimes our arms into a wall or ceiling to fish for a wire. The beauty of making all of the holes 4 inches and round is that it makes our job easier and the person who follows to do the repairs. They can simply take a sheet of drywall and use – you guessed it – a 4” hole saw to drill out the “pucks” to fill in the hole we made. Simple and quicker to repair than a bunch of holes made with a hammer or with a drywall saw with holes all different sizes.
Most homes with K&T also have lath and plaster walls and ceilings. All of the receptacle and switch boxes have to be removed and require TLC when doing so. If you go to fast or are too rough removing the box big chunks of plaster can also come with it. We have a few tricks up our sleeve to ensure most of the time this is avoided.
Finally, as the saying goes, measure twice, cut once. We don’t go into rooms with drills a blazing and start indiscriminately cutting holes in the walls. I look at a K&T rewire as a puzzle or maze to be navigated. You need to take a few extra minutes and think about the options for rewiring in the room or floor. What happens if a room has old wall paper that needs to be preserved? Often you can make holes in adjoining rooms to rewire the plugs and switches where the wall paper is. Have to bring wire from first to second floor? Maybe you go down before going up. I really do believe that for every 10 minutes planning you save an hour in the end. In a K&T rewire it pays to consider your options before blazing ahead.
Minimize the Mess
If you minimize the damage you definitely make less of a mess however, K&T rewires are dusty no matter how careful you are. When cutting a hole in a wall or ceiling you will get plaster dust and insulation falling out. Before working in any room you need to cover everything with plastic and put drop sheets on the floor. We also have special attachments for our drills that capture most of the dust during drilling. Sometimes we will use a shop-vac to suck the dust up while drilling.
Minimize the Disruption to the Customer
When we leave for the day and the customer comes home I only want them to know that we were there because there are some holes in the wall. I don’t want them to see dust on the floor, lights not working or no receptacles available to plug things into. All of these things will upset your routine and cause you stress.
When we complete a K&T rewire ideally we clean up fully after each day, especially in areas like kitchens, bedrooms, bathrooms and common areas. To say it will look like Mr. Clean stopped by is a stretch but you can do a reasonable job with a broom and shop-vac and maybe a wet cloth in some areas.
When you do a K&T rewire you need to remove all switches, receptacles and lights where the K&T wire is existing. For efficiency and practical reasons we like to remove everything at once. For convenience we put temporary lights, switches and receptacles so the customer can live a normal life during the rewiring job.
Eliminate Safety Hazards
When putting temporary lights, switches and receptacles we do not put them in boxes until the new wiring has been run. For that reason we tape up the switches and receptacles so that no live parts are exposed to cause a shock. If a customer has young children, pets or both who more than likely be tempted to touch something out of the ordinary we put on cover plates and fasten all accessible plugs and switches to the wall to prevent a shock.
Job Well Done
If done properly a K&T rewire does not have to be a traumatic experience. If I am able to meet all of my objectives for a successful K&T job I will be satisfied and most likely the customer will to. It is irksome that you have to lay out all that money (a whole house rewire is not inexpensive) where at the end of the job all you see are a bunch of holes in the walls. It’s not like a home decorating project or landscape project where the results are beautifully evident in the end. For a K&T rewire you have to be content to know that you now have up to date electrical wiring and you can get on with some other renovations you may have been delaying because of the old wiring.
Attila Fust – Owner – Wattsource Electrical