Knob and tube wiring?

23 Replies

Found a duplex in Grand Rapids I like but it has knob and tube. It's functioning but how concerned should I be?

I've seen people say walk away whenever you encounter it and others who say it's not that big of a deal.

I'm assuming it's not uncommon in Grand Rapids given the ages of a lot of the homes?

@Jason Carter I would look at it as a liability/maintenance cost. In order to sell it again you may need to update it. For insurance you may need to update it. For code you may need to update it.... 

Is there room in the budget to replace it?

Exactly jason. No problem as long as the price is right and you have the budget to update it. Same goes for just about anything. Other than the neighborhood the home sits in 😁

We looked at a KnT property but wouldn't E had to fully rewire it which meant a full gut. All the old plaster walls would have had to be redone or replaced with drywall.

Sorry...posting on my phone. Anywho, we would have had to replace all of the wiring before even being insured. The cost was prohibitive and the wiring not in good shape. So we passed on the opportunity.

Given its a rental, i would be concerned.  Renters dont care about the wiring in the walls, and could very easily over load circuits, which is the concern with knob and tube fires. Another issue is insurance, which could be a deal killer.  Not knowing the size of the house, its hard to say what it would cost.

Also, a house can be rewired without a full gut.  Yes there will be access holes that the electricans make that need to be patched, but a good electrician can rewire without removing the walls, just like a good plumber can repipe (water service) without removing the walls.

You should be moderately concerned. Is it going to catch fire right after you close? Not likely....but not impossible. That old stuff is problematic, and should be replaced whenever opportunity arises. But that's a definite expense.

If the property is priced appropriately, it can be fine. But don't buy it without factoring replacement expense in sometime down the road.

I just spent $8000+ getting all new wiring in a 1344 square foot house.  The walls will have to be redone also. 

Hope that helps with a guess on how much of an issue it might be.

The only good advice I see is from @Mike Wood , and I will confirm, based on experience as a contractor, that you don't need to rip walls out nor require a gut, at max, yes there will be holes, but we could easily patch it. 8k would sound about right for less than 2000sf and single storey. Concerns? I don't see any. Your only concern is finding a good contractor to do the job right and update budget, perhaps even a little buffer. If you have those, I don't see any reason why you should walk.

The other issue you have with knob and tube is that you cant add to it.  Your best bet is to replace it.  Its not that painful and your tenants will not run into issues with blowing fuses and over loading circuits.  Plus you can then seperate the duplex correctly so they pay for their own electric.

Budget for it and upgrade to circuit breakers.  No reason to pass up on a deal because of knob and tube.

If it will be a rental, it won't pass inspection.  I'd recommend getting a copy of the 2012 International Property Maintenance Code (IPMC).  This is the code that most communities use to enforce certifications of rentals.  It's likely the service panel will have to be upgraded too.  If you're looking to sell to anyone as a owner occupied other than a cash buyer with no inspections, you'll probably run into stumbling blocks on financing and/or insurance. 

Jason, obviously I will let you do your due diligence on this issue however I am going to challenge Clay on his quote "If it will be a rental, it won't pass inspection."   If you visit this page http://grcity.us/community-development/Code-Compli...  you can look up and confirm that this house has been inspected and certified by the City of Grand Rapids as a rental.  

I own several houses with knob and tube and although they are not as desirable as updated electrical never will an inspector require you to update and entire house if the knob and tube insulation or insulators are not compromised.  

With any of my homes that have knob and tube I update the panel from fuses to breakers to ensure that the breaker will trip if overloaded.  This upgrade in Grand Rapids typically cost 1500.00 per panel.  In a duplex we are often able to get the both panels replaces for around 2000.00 which includes permits. 

Please keep in mind that these are opinions. 

I can also confirm the city will verify the property. I bought a two unit in August. It had knob & tube wiring and received a three year inspection certificate in July.

Thanks, Tim and Andy, I did overstate the case unintentionally.  You're right, as long as the electrical service provides grounded, three-wire, 120/240 volt, single-phase service with a  minimum of 60 amps it should be good--at least for rentals. My brain was visualizing some of the older housing which has two-wire knob and tube.

Buyers should be aware that some previous owners may have hoodwinked inspectors, etc. by only replacing non-compliant wiring in the area where it can be seen.  (@Andy W. , do you mean 4 year cert?  Just making sure as GR offers 2, 4 or 6 year certs...was your property in Wyoming or Kentwood?)

Thanks everyone! Great input here. It's a big help. Think we're going to have an electrician take a closer look and see if Tim's solution will work. 

@Jason Carter  People who are reading this post who are worried about it catching fire I think are missing the point.  If it has not produced a fire in the last 50 years, why would it now?  But that's not really the point.  I have had to go through this myself and yes 100% I firmly believe you should get rid of it.  Selling a house at retail (should things go wrong on the rental side) with Knob and tube proves to be very difficult and like another person mentioned you usually don't have to do a full gut.  IMHO you build it in to the price and do it the right way upfront.  From a different angle a 4 yr old boy was killed in a house fire in my town just 2 weeks ago, that was suspected to be an electrical issue.  Not sure if it was Knob and Tube, but I am very sure you don't want that on your mind for the rest of your life either.

My personal home has knob and tube wiring and galvanized piping which I personally want to replace, however, the USDA does a thorough inspection and they passed this house for the USDA guaranteed loan......and I have insurance 800$ a years. I know rentals may be a bit different. 

Originally posted by :
Andy, do you mean 4 year cert?  Just making sure as GR offers 2, 4 or 6 year certs.

You're right @Clay Powell . I just checked and it's a 4-year cert, expiring 2018. I must have had my dates mixed up. The property is in lower Creston, close to Sun Title.

Glad to hear, @Andy W. .  As you probably are aware, a big part of my job is advocating for landlords concerning city issues with inspections.  I was hopeful that the City of GR wasn't trying to slip one past us.  As you probably know, inspectors often make things up as they go...especially the newer ones.  I try to keep my pulse on what is happening.  Any hey, I'm really happy to hear you got your four year...make sure to ask for a six year the next time. : )

  1. Originally posted by @Clay Powell :
  2. Thanks, Tim and Andy, I did overstate the case unintentionally.  You're right, as long as the electrical service provides grounded, three-wire, 120/240 volt, single-phase service with a  minimum of 60 amps it should be good--at least for rentals. My brain was visualizing some of the older housing which has two-wire knob and tube.

Every K-n-T I've seen is two wire 120 only, ungrounded, with a twist-fuse in the distribution panel, and only 15amp.  Few outlets in any room and the tenant will use extension cords with multiple outlets leading blown fuses, which are hard to obtain.

Having crawled under a the floor, I've seen rotted insulation falling off the wire - - and that indicates the same condition withing the walls.  In that day, insulation was fabric wrapped wire.

These 20's and 30's homes can be interesting architecture, buy REI's aren't architecture preservationists (baring Queen Ann and Victorians), so you've got a major GUT and restyle project IMO.



NA BeardYour observation from experience is the same “vision” that I had in my mind when first reading and responding to Jason's original question…hence the reason I responded initially the way I did. This house may be in compliance—wouldn’t know without seeing it. My follow up comment was the bare minimum standard and straight from the 2012 IPMC. The IPMC is the code for rental properties in Grand Rapids. The City of GR is pretty picky. If this property has passed inspection for a rental, it may be up to the property maintenance code in the eyes of the City.

On one particular project I had an electrician tell me his biggest concern was KnT in the attic covered by blown or other insulation. His theory was the worst condition was to have wire getting hot and not being able to adequately dissipate the heat, especially if there had been traffic in the attic disturbing the wiring. Although not ideal he was comfortable with leaving KnT in the walls and just replacing it in the attic. It could be an interim option for you for cost savings.

A side benefit in my area is that the power company offers a rebate for adding attic insulation...the old just has to be removed before they perform their audit.

Once a wall is opened you'll have to update. If it stays it will usually be fine. I had one unit that I gutted updated and can recommend a crew that did great work and were the most affordable if you pm me. 

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