Insulation/K&T Wiring/Rewiring

[gc4elec]

I have a home that is part 1940 and part 2005. The new portion is all new (well 2005 new) romex with grounds. The old is some rewired romex with grounds and some knob and tube (K&T) without grounds. Spoke with electrician and they recommended/installed a whole house surge protector and GFCI outlets on ungrounded K&T since rewiring gets very expensive. They said the K&T wiring in the walls that they saw looked AOK. Welcome thoughts on this - the work is already done and they're reputable but probably should've asked forum beforehand. I would like to rewire all eventually but it is not a top priority project and opinions on K&T vary - some say it is AOK and keep it others say no. Welcome thoughts on this too.

Anyway, I need to insulate the 1940 house and am redoing siding. Considering having a foam insulation company spray foam in from the outside pre changing siding since much easier than tearing up inner walls. However, I will bury all K&T wiring in the foam so...questions:

How hard is rewiring with vs without foam insulation in wall joists?
Should I avoid foam at all costs before rewiring?

It seems some walls are going to have to be opened to rewire so I'm thinking foam may not matter much. I also gather it may be easier to just cut the K&T leaving dead wires in the walls when eventually rewiring.

Welcome thoughts on all of this. The house is drafty so I'd like to insulate ASAP.

Thanks

 

[Petej999]

I would avoid insulating until you get the electrics sorted.

 

[Megawatt]

I have a home that is part 1940 and part 2005. The new portion is all new (well 2005 new) romex with grounds. The old is some rewired romex with grounds and some knob and tube (K&T) without grounds. Spoke with electrician and they recommended/installed a whole house surge protector and GFCI outlets on ungrounded K&T since rewiring gets very expensive. They said the K&T wiring in the walls that they saw looked AOK. Welcome thoughts on this - the work is already done and they're reputable but probably should've asked forum beforehand. I would like to rewire all eventually but it is not a top priority project and opinions on K&T vary - some say it is AOK and keep it others say no. Welcome thoughts on this too.

Anyway, I need to insulate the 1940 house and am redoing siding. Considering having a foam insulation company spray foam in from the outside pre changing siding since much easier than tearing up inner walls. However, I will bury all K&T wiring in the foam so...questions:

How hard is rewiring with vs without foam insulation in wall joists?
Should I avoid foam at all costs before rewiring?

It seems some walls are going to have to be opened to rewire so I'm thinking foam may not matter much. I also gather it may be easier to just cut the K&T leaving dead wires in the walls when eventually rewiring.

Welcome thoughts on all of this. The house is drafty so I'd like to insulate ASAP.

Thanks

You better find out if the foam is fire proof, the other week they put 2 people in jail because they owned a night club and neighbors started complaining about the loud music so they thought they would spray foam to sound proof inside the walls of the building and they had a fire and the whole club was fully engulfed in around 20 minutes. Just something to think about. It’s a really a hard job totally rewiring a house. I would get rid of the knob and tube wiring and pull all circuits new that it serves. You might have some old wiring from the 40’s but it’s been in the wall all these years and I doubt is bad.

 

[Megawatt]

You better find out if the foam is fire proof, the other week they put 2 people in jail because they owned a night club and neighbors started complaining about the loud music so they thought they would spray foam to sound proof inside the walls of the building and they had a fire and the whole club was fully engulfed in around 20 minutes. Just something to think about. It’s a really a hard job totally rewiring a house. I would get rid of the knob and tube wiring and pull all circuits new that it serves. You might have some old wiring from the 40’s but it’s been in the wall all these years and I doubt is bad.

The circuits that you say has no ground you can install GFCI breakers to protect them