Rewiring a block basement

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Ebm17

New member
Location
Orlando, fl
I am remodeling my house and considering several options for desiring the basement. I plan to hire a licensed electrician to perform the work but feel I need to be better educated to make the right decision. I have been given three options for desiring the basement and don't know which is more cost effective. The entire basement is block walls with a poured top course and concrete foundation. The first option is to just fur out the walls, run the wire along the walls and then drywall over. Electrical cost is low but drywalling is expensive and all moulding needs to be reset. The second option is to try to fish the line through the voids in the block. We would then go back and repair damage as necessary. In this option, I don't understand how the electrician would exit the block wall at the top where the courses are poured. Can anyone suggest which option is most cost effective? Are there other options?
 

Speshulk

Senior Member
Location
NY
A couple things:

1. Your spell check doesn't like the word "rewiring."

2. You said 3 options then listed 2.

3. Neither of those 2 options sounds like a cheap electrical installation. The cheapest electrical installation is going to be to stud up full walls inside the block. Your second option sounds like a lot of work for little gain. If you would just end up seeing the block at the end of the job anyway, then surface mount your electrical in EMT and avoid patching the block.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I will leave this open as long as posts are in line with "which is the most cost effective".
As the poster is not in the electrical field, please do not post "how to".
 

jumper

Senior Member
I am not a contractor so I know nothing about about pricing, but I am a home owner, so I am going to post my advice as such.

If are not experienced at this sort of thing and do not have a plan for the final design of the basement, then what is the most cost effective solution now can be a waste of money later when you change your mind.

Home owners tend to end up losing money when trying and do this type of thing themselves. I suggest seeking the advice of a design professional that knows how and can coordinate the services of all trades involved.

Trying to be your own General Contractor can be real expensive. I do not do it and advise against it.

Just my .02 cents.
 

renosteinke

Senior Member
Location
NE Arkansas
Finishing a block basement presents it's own challenges. Indeed, simply finishing any sort of basement has a few challenges. You'll find I have posted extensively on the more general construction details at the FineHomeBuilding forum. You can PM me if you'd like me to repeat these details.

To get electric in your basement, the most practical manner is likely to be an exposed system, with the boxes mounted to the face of the wall and the wires run in pipe (EMT), also on the face of the walls. If you later add drywall, you can 'extend' the boxes so that they project through the new wall faces.

Simple firring strips to support drywall will not give you enough space to run cables ("Romex") unprotected through the cavities. The firring would need to be at least 'nominal' 2x2's, and the inspector might insist upon 2x3's.

Coming down through the block cavities is generally not practical unless it's done during the original construction. As the wall is a foundation wall, it could very well have had the cavities filled with mortar. There is also some debate whether you're allowed to run cables through this sort of wall; some would consider it a "wet" location.

"Cost effective" is a rather mushy term. Often, it's a fancy way of saying 'cheap.' The most cost effective manner is the one that best suits your actual needs. Good design is about much more than simple price. You'll have to make plenty of other decisions for this remodel, and the cost of the electrical work is the least of your worries.
 

satcom

Senior Member
Finishing a block basement presents it's own challenges. Indeed, simply finishing any sort of basement has a few challenges. You'll find I have posted extensively on the more general construction details at the FineHomeBuilding forum. You can PM me if you'd like me to repeat these details.

To get electric in your basement, the most practical manner is likely to be an exposed system, with the boxes mounted to the face of the wall and the wires run in pipe (EMT), also on the face of the walls. If you later add drywall, you can 'extend' the boxes so that they project through the new wall faces.

Simple firring strips to support drywall will not give you enough space to run cables ("Romex") unprotected through the cavities. The firring would need to be at least 'nominal' 2x2's, and the inspector might insist upon 2x3's.

Coming down through the block cavities is generally not practical unless it's done during the original construction. As the wall is a foundation wall, it could very well have had the cavities filled with mortar. There is also some debate whether you're allowed to run cables through this sort of wall; some would consider it a "wet" location.

"Cost effective" is a rather mushy term. Often, it's a fancy way of saying 'cheap.' The most cost effective manner is the one that best suits your actual needs. Good design is about much more than simple price. You'll have to make plenty of other decisions for this remodel, and the cost of the electrical work is the least of your worries.

The firring strips went out with the construction of the 50,s and 60,s today a they use 2x4 and size up to allow for insulation and wiring space, have some handy dandy expert contractor do your basement and it may be the most expensive basement job in the long term, the demo cost when you sell, may cost your more when it hold up a sale closing until the, the basement is made right, and all the violations are removed, we see it every day, and it is not just bad electrical, it is everything from missing construction permits, to faulty construction. Do it right the first time and save big money.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
I am remodeling my house and considering several options for desiring the basement. I plan to hire a licensed electrician to perform the work but feel I need to be better educated to make the right decision. I have been given three options for desiring the basement and don't know which is more cost effective. The entire basement is block walls with a poured top course and concrete foundation. The first option is to just fur out the walls, run the wire along the walls and then drywall over. Electrical cost is low but drywalling is expensive and all moulding needs to be reset. The second option is to try to fish the line through the voids in the block. We would then go back and repair damage as necessary. In this option, I don't understand how the electrician would exit the block wall at the top where the courses are poured. Can anyone suggest which option is most cost effective? Are there other options?

lf it were my basement:

i'd use 4s boxes 1 5/8" deep, and connect them with emt, as suggested here already. surface mount them, and
do a tidy job. use raised industrial covers with decora devices.

you are done.

if at some point in the future, you decide you really want finished walls, you can do this...

lay the studs flat. take off the raised covers, and replace them with single gang 1/2" raised plaster rings,
drywall the walls, put the devices back into the boxes, and you are done. if you need a full 3 1/2" for
insulation plumbing, whatever, put the studs normally, and use a 1 5/8" extension ring on the 4s boxes,
put a plaster ring on top of that, and drywall. replace the devices, you are done.

if you are gonna finish the walls, and you know this, then fir the walls out with 2x4's, and wire with standard
plastic boxes and romex.

anything else you do is going to suck, imho.

a decent electrician can do this in less than a day. so what we are talking about, is a days wages,
and the material... and a permit.
 
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iwire

Moderator
Staff member
Location
Massachusetts
Simple firring strips to support drywall will not give you enough space to run cables ("Romex") unprotected through the cavities. The firring would need to be at least 'nominal' 2x2's, and the inspector might insist upon 2x3's.

I will ask you to post the code section number that you believe supports your opinion above.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I will ask you to post the code section number that you believe supports your opinion above.

I wondered about that myself. as long as the romex is protected with metal nail plates where it passes thru the firring strips, I don't see any electrical code requirement that they be any special thickness. You might have an issue with getting the boxes to fit and not stick out, but that is appearance and not code IMO.
 

renosteinke

Senior Member
Location
NE Arkansas
Ordinary firring strips are of 1x lumber, and measure appx. 3/4" thick. (Some other methods are even thinner). This is substantially less than the 1-1/2" required space from the face of the wall to the unprotected Romex. You'd be required to 'nail plate' the entire length of the cable.

"2x" lumber measures about 1-1/2" square, and ought to be enough once you add the drywall, but I have seen the point disputed. hence, my reference to the wider 2x3; at least it is possible to notch the backside of the 2x3 to allow cables to pass beyond the reach of the usual drywall screws.

I fully agree that it is common these days to have 'free-standing,' framed walls, rather than building up the existing block.

I did not want this to become a 'how to remodel a basement' thread. I have written extenensively on the topic for other publishers, and I know just how lively the discussion can / WILL become.

I agree that there are many other factors to consider, apart from the electrical. We have all absolutely encountered botched jobs. Again, I was trying to remain quite close to the OP's question.
 

renosteinke

Senior Member
Location
NE Arkansas
Oh, for citations:

Look to 300.4 for the depth requirements for 'bored holes.' 334.17 expands this to NM 'through or parallel to' framing members. 334.10(B) applies it to NMC in a 'shallow chase,' while 334.12(B)(3) bans NM from a 'shallow chase.' Yet, the 'shallow chase' they describe seems to be one cut into masonry, then filled with with some form of patch.

So, I guess you'd have to say I infer a requirement that the cables be kept back from the face of the wall for their entire length.

Having just demo'd a wall that had panelling applied, with 2" brads everywhere, I really don't want to see the cable run right under the drywall .... as had been done on this wall.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Ordinary firring strips are of 1x lumber, and measure appx. 3/4" thick. (Some other methods are even thinner). This is substantially less than the 1-1/2" required space from the face of the wall to the unprotected Romex. You'd be required to 'nail plate' the entire length of the cable.
.........................................................

I don't see 300.4(D) requiring that. As long as the NM is 1/1/4 from "the edge of the framing member", I accept it.
I have seen some "stack-its" for furring strips that accomplish this as well as other methods.
I do not care for the furring strip methods as to the problems associated with installing a box with adequate depth, but I don't reject NM that is 1-1/4 from the edge.
 

iwire

Moderator
Staff member
Location
Massachusetts
I don't see 300.4(D) requiring that. As long as the NM is 1/1/4 from "the edge of the framing member", I accept it.
I have seen some "stack-its" for furring strips that accomplish this as well as other methods.

Exactly, we have to do this often in commercial work, walls of hotel rooms are often just metal strapping on block.

Nail plates needed where we are close to framing members. 1.25" under the NEC only .75" under the Mass codes.

I do not care for the furring strip methods as to the problems associated with installing a box with adequate depth

Same here, it is a pain in the nads. We will blow out the space in the block we need with a demo hammer.
 

iwire

Moderator
Staff member
Location
Massachusetts
Ordinary firring strips are of 1x lumber, and measure appx. 3/4" thick. (Some other methods are even thinner). This is substantially less than the 1-1/2" required space from the face of the wall to the unprotected Romex. You'd be required to 'nail plate' the entire length of the cable.

There is no NEC rule that requires NM be more than the 1-1/2" from the face of the wall to the unprotected Romex.
 

renosteinke

Senior Member
Location
NE Arkansas
So, Iwire ... to go off on a slight tangent, you find no code issue with someone running the cables right behind the baseboard, without an metal plate?
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
So, Iwire ... to go off on a slight tangent, you find no code issue with someone running the cables right behind the baseboard, without an metal plate?
Assuming that the NM is at least 1.5" away from the nearest framing member of furring strip, I do not see a code issue. I would not install NM there, but the code permits it. 300.4(D).
 

iwire

Moderator
Staff member
Location
Massachusetts
So, Iwire ... to go off on a slight tangent, you find no code issue with someone running the cables right behind the baseboard, without an metal plate?

No, not directly.

Meaning there is no specific code that prohibits running NM as you describe.

When we do it we generally go horizontal above baseboard level but below receptacles.
 

renosteinke

Senior Member
Location
NE Arkansas
I don't want to hijack the thread ... so, I'll save the baseboard issue for another discussion. Just wanted to be sure I understood your position.

With the code mentioning the required distance for cables run 'parallel' to framing members ... I suppose I'll have to make sure everything is at a slight angle :D
 
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