Knob and spool

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normbac

Senior Member
I am trying to bid a rewire of a home that is knob and spool and am cluless to the time it might take to do the job. Lath and plaster is staying up except where needed to be broken for new electrical installations. All wiring to be rewired to 05 codes, basic older home. House is single story on a raised foundation and attic has blown insulation.

Would appreciate any input. TIA
 

R2006

Member
Location
PENNSYLVANIA
Hi Norm

Hard To Say. How Many Rooms? Interior Walls Should Go Quickly Exterior A Little Langer. What Kind Of Shap Is The Plaster In And Is It Wood Lath Or Wire? Rancher With Full Attic And Basement Shouldnt Be Too Bad Though. Good Luck.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
normbac said:
All wiring to be rewired to 05 codes, basic older home.
Are you saying that the end result is to have the home wired as if it had been built under the 2005 NEC? That'll take a lot of time and a lot of the clients money.

Around my area, there are jurisdictions that spell out the minimum electrical configuration an existing dwelling must meet when a service size increase occurs or when a fuse center is changed out with an equal sized circuit breaker center.

And there are also jurisdictions that only require the "obvious hazards" to be repaired or removed.

None require a total upgrade to current new construction codes.

What are the requirements published by your prospective job's jurisdiction?
 

normbac

Senior Member
al hildenbrand said:
Are you saying that the end result is to have the home wired as if it had been built under the 2005 NEC? That'll take a lot of time and a lot of the clients money.

Around my area, there are jurisdictions that spell out the minimum electrical configuration an existing dwelling must meet when a service size increase occurs or when a fuse center is changed out with an equal sized circuit breaker center.

And there are also jurisdictions that only require the "obvious hazards" to be repaired or removed.

None require a total upgrade to current new construction codes.

What are the requirements published by your prospective job's jurisdiction?

Was a general statement homeowner wants updated didnt specify o5 will be looking at job friday,since I never did this before I wasnt sure how to figure man hours without burying myself 4 bedroom liv kit fam 1700 sq ft
 

satcom

Senior Member
They just finished one across town, 1500sq 3 bedroom, 1 bath, kitchen, dining room, living room, enclosed porch, $28K and the EC is crying, he lost his shirt, it was a complete rewire, lath, and plaster, ceiling and walls, no insulation.

Work like that is 3 or 4 times the open construction estimates.
 

jeff43222

Senior Member
So who gets to decide where "Lath and plaster is staying up except where needed to be broken..."?

Basically, this is a new construction, plus demo of the old, plus lath and plaster more or less in the way everywhere.

If the plan is do do a complete rewire, I don't think I'd take the job unless I got to decide how much demo needs to be done (a lot). Also, I'd want someone else to demo the walls. Given that, I don't see how it's practical to leave up scraps of plaster/lath.

I'd try to talk the homeowner into gutting the place if he is really insistent on a complete rewire.

As for how to bid it, I'd say bid it high, then add 50%. Either that, or T&M.
 

resistance

Senior Member
Location
WA
I just did the same thing two months ago, yet it had a main floor and basement. The customer removed all the blown in insulation (help greatly), and the attic had stand-up walking room. It took one guy 8 days. If you are down on your knees under the house, and moving insulation in the attic--with no real room to move around, then I can see this job--depending on the sqft, taking over 11 working days for one guy.
 
No HO is letting this go at T&M.
this HO should be wanting to get rid of the L&P. So this tells us he's either cheap or stupid. Cheap & stupid people always pay twice & complain twice.
I say double your bid, do it right for him the first time, he'll only complain once.
& while your at it print out this thread & show it with your bid! LMAO!
 

satcom

Senior Member
"So who gets to decide where "Lath and plaster is staying up except where needed to be broken..."?"

You don't need to do much demo, most of those homes had balloon construction, the outlets can usually be fished, and the plaster, and lath cut outs can be made without much damage, madison holders make a secure box, the older craftsman, could rewire these jobs with little or no damage.
 

satcom

Senior Member
"No HO is letting this go at T&M."

Your right on that one, the rewire on older homes will depend on the job conditions, we have an ec, from the next town, that does a lot of these older home rewires, if they gut the house, it's close to a new stick job, if they let you make openings rather then cut outs the time is also less, but if they want neat cut outs, and they have wall paper, all over the home , your in for a treat, and some of these older homes, have boxed frames, with cross supports, that can add many hours to the job, attic crawls, are another killer, not every home is the same, so each rewire will be different.
 

jeff43222

Senior Member
satcom said:
"So who gets to decide where "Lath and plaster is staying up except where needed to be broken..."?"

You don't need to do much demo, most of those homes had balloon construction, the outlets can usually be fished, and the plaster, and lath cut outs can be made without much damage, madison holders make a secure box, the older craftsman, could rewire these jobs with little or no damage.

I don't see much balloon framing in the old houses I work in, but I run across plenty of plaster on lath. Fishing takes a lot more time than open construction, and I certainly don't want to have to fish between floors every time I want to run a cable from one outlet to the next.

Cutouts are often tricky with plaster on lath. You have to take extra time with the plaster to avoid cracking it or making the hole bigger than you want. Then there's the fun of cutting the lath without causing it to bang around on the plaster (and break it). Sure, RotoZips prevent that scenario, but they aren't so great, either.

I agree that Madisons are a good way to support boxes if you're going to cut into plaster walls.

So I agree that it's possible to do a job like this without doing demo, but it would cost a whole lot more. I would charge several times what I would for new construction if the plaster and lath has to remain in place.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
In my opinion, the art of bidding the "rewire" of an existing dwelling with Knob and Tube in it is to:
  1. Know the minimum electrical requirements that the local ordinances impose on the dwelling and
  2. Identify the deficiencies in the existing wiring system in the building. The homeowner will have to have the deficiencies met, as a baseline cost.
  3. Include in the baseline cost the repair or removal of any obvious electrical hazards.
  4. Identify existing load and learn from the homeowner what changes in the load will likely happen in the foreseeable future.
  5. Identify what the homeowner wants in the way of electrical convenience, that is, the computer work station here, the entertainment there, nothing in particular in that third area, the glitzy luminaires around the corner, etc. And then price those electrical installations individually, to the extent possible.
  6. Present the baseline cost as un-negotiable, and let the homeowner pick and choose from his/her wish list.
 

ceknight

Senior Member
normbac said:
I am trying to bid a rewire of a home that is knob and spool and am cluless to the time it might take to do the job. Lath and plaster is staying up except where needed to be broken for new electrical installations. All wiring to be rewired to 05 codes, basic older home. House is single story on a raised foundation and attic has blown insulation.

Single floor, access from underneath and overhead? Sounds like a straightforward old-work rewire to me, nothing terribly complicated other than the insulation you'll be rolling in when you put in the new ceiling boxes. No demo necessary.

The old wiring's pretty much irrelevent, this is bypass surgery -- disconnect it all, remove what you can and tag/deadend the rest. Then it's straightforward fishing. Do everything vertically, if you absolutely have to go horizontal within a wallspace, do it behind the baseboards. Don't fight the house, work with it. Etc.

I know a lot of folks bid these T&M, but old work's pretty much all I do and I do it by the hole. I expect things to average out in my favor over a whole house rewire -- for every tough outlet, you're going to have a few easy ones. I find it's a lot more profitable that way, and customers are able to budget for the work better. You just tell 'em what an outlet's going to cost, and every time they want to make a change, they know what to expect.

Only you can determine what that per-hole cost should be, it has to match your circumstances and experience, but don't sell it short. You're charging for the run, the hole, the fishing, that mouth full of insulation or crawlspace dust, etc. A good guestimate would be take your standard fee for an outlet in new construction, add $50-$70 to that, and you're in the right ballpark.

Good luck, sounds like fun!
 

hillbilly

Senior Member
I work on a lot of older homes and most of them have plaster and lath.
Things to look for:
Crawl space access (if it has a basement, it's a big advantage)
Attic access and type of insulation (blown in is a problem, especially if it's old because it'll be very dusty with old rat, bat, squirrel and bug droppings when you start digging around in it.).
On a total re-wire I would figure on (someone else) removing all of the insulation and replacing it when I was finished. Add it in your bid. It will save you a lot of grief and the customer will have a more energy efficient home..
Type of plaster and lath construction (plaster on lath or steel mesh?) Wood lath is better and easier on your tools.
Do the walls have horizontal blocking? If so, this is a problem and a big add-on.
Some older homes have a overlay of sheetrock (remodel) on the plaster.
If so, look for the ceilings (and maybe the walls) to be about 1 1/4" thick and hard to cut.
Use a sawzall with a (short) carbide blade to make your cuts in the plaster.
Don't try to be conservative on the holes. Cut as many and as large as you need to get the work done efficiently. Drywall patch works well on plaster and is cheap compared to the labor needed if you don't have working room.
Any wall paper repairs will be by the customer.
Bid it high....You don't want to do all of that hard work and wind up breaking even or worse. If you get it good, if you don't, someone else will suffer.
Give a specific number of receptacles, switches and light openings on your bid. Anything else will be T&M.
If you've never done re-model on plaster walls and ceilings, you're in for a education.
Sorry for the long post, and I'm not trying to scare you but there are a lot of "tricks of the trade" when it comes to this type of work.
To sum it up....BID IT HIGH.
Just my 2 cents.
steve
 

ceknight

Senior Member
al hildenbrand said:
In my opinion, the art of bidding the "rewire" of an existing dwelling with Knob and Tube in it is to: (list snipped)

Sage advice, from someone who knows. Listen to Al. :)
 

JohnE

Senior Member
Location
Milford, MA
On the few complete rewires I've done involving wood lathe and plaster it would have been cheaper if they gutted the place, wired like new construction and then plastered or drywalled. Short of that, Al's right on the money.
 

JHarvey

Member
Location
Topeka Ks
Lath and Plaster

Lath and Plaster

If you run into a situation where the plaster has to be saved, plan on taking your time cutting the opening. Try to hurry it and you'll wind up with a big blow out of plaster. Been there done that got the A$$ chewing for it. LOL
Good luck.

J.Harvey
 
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