# Rewire Concrete Block House



## JeepNick (Oct 27, 2011)

*Rewire Concrete Block House - Question on furring walls?*

I have a 1953 ranch house in Phoenix, AZ, built with 4x8x16 concrete block. I had a new service/panel put in a few years back, but the rest of the wiring has never been updated and is still un-grounded. 

I'm planning an addition that will increase the square footage of the house by about 45%. The work will largely be completed by yours truly. I've built large additions before (permited and inspected), so I'm up to the task.

I have three questions for you guys. 

*1. * If I want to/have to rewire the existing structure to bring the whole house into current code compliance, that means running new wire to outlets in some concrete block walls (the main structural walls of the house). My chances of pulling new wire in the walls is slim to none. Alternatively I want to fur out the walls, add some rigid foam insulation, run electric and networking cables, and then slap drywall over the top of the walls, covering it all up. 

Do I need to protect the electrical wire and/or networking cable in metal conduit within the furred out area, or can the wires be fastened to the side of the furring, or to the original concrete wall with no conduit required for protection from nails, etc? If I have to run conduit, is it permissible to run it in a "groove" carved out from the rigid foam insulation?

*2. *If I have to bring the whole house into compliance, does that also extend to outlet spacing? For instance, the existing living room has four outlets - One on each wall. They aren't spaced per current code. Do I need more to come into compliance? I may add more because I want them, but do I have to?

*3. * This relates to requirements to bring the whole house into compliance. I thought I read a code requirement a few years back that said if your addition increases the livable space but more than X%, you had to bring the entire structure into electrical compliance. Does this sound right? I've searched and searched for this language, but my city changed codes on me in the two years since my last big project...

For reference, Phoenix is now on 2011 NEC, 2012 ICC, 2012 IRC.

Thank you for your input and assistance! :thumbup:


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## plummen (Jan 10, 2010)

JeepNick said:


> I have a 1953 ranch house in Phoenix, AZ, built with 4x8x16 concrete block. I had a new service/panel put in a few years back, but the rest of the wiring has never been updated and is still un-grounded.
> 
> I'm planning an addition that will increase the square footage of the house by about 45%. The work will largely be completed by yours truly. I've built large additions before (permited and inspected), so I'm up to the task.
> 
> ...


If youre going to fur the walls out with 2x2s I personally would atleast mount 4x4 metal boxes and plaster rings to the wall for the plugs then run conduit above the finished ceiling level to protect the romex.
As far as being required to bring the whole house up to code if say it depends on your city inspectors.
If youre not opening any walls in a room they usually wont make you upgrade it around here anyway.


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## Jim Port (Sep 21, 2007)

You will need to find out if your area has a rehab code or will require complete compliance with the current codes.

As long as the cables are at least 1.25" off the face of the furring strips they would not require protection.


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## k_buz (Mar 22, 2012)

Have you considered what furring out these walls will do to window/door frames?


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## joecaption (Nov 30, 2011)

A lot easier to use 2 X 3's and build a whole new wall in front of the block wall.
You will have more room for insulation, you can use deeper electrical box's making wiring connections easy, no need attach the new studded wall directly to the block wall.
You will find it hard to find straight 2 X 2's and when you try to attach them your going to find it hard to get fasteners to hold and the 2 X 2's will keep splitting.
Drill the holes for the wires at the back of the 2 X 3 and you can meet the set back rule and not have to keep running the wires all the way up into the attic and pulling it back down again at every outlet.
What I did was lay all the wall studs down standing on end and clamped them together, then used a router with a 3/4 straight bit to premake a cut out for the wiring.
Once the wall was up you'll need to make jamb extensions for all the windows and doors.
When I did mine I made sure to have an outlet under every window, makes it easy to plug in a Christmas candle.


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## JeepNick (Oct 27, 2011)

joecaption said:


> A lot easier to use 2 X 3's and build a whole new wall in front of the block wall.


I had thought about this. I'm also thinking about using a metal furring called "Z-Furring Channels". I like the simplicity, and I think I can just drill a hole to run wire through them in order to chain outlets.




k_buz said:


> Have you considered what furring out these walls will do to window/door frames?


All doors and windows will be getting replaced during the project. Furring and drywall will actually make finishing the new windows and doors, easier.


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## plummen (Jan 10, 2010)

k_buz said:


> Have you considered what furring out these walls will do to window/door frames?


Just extend the sills/jambs.


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