wiring up a brick wall

[William.Deans]

Greetings,

I have a row home (townhouse) which shares a common brick wall with the neighboring house. The wall is coated with about 1/2" of mortar followed by a skim coat of plaster and then 100 years of paint. I need to install some outlets along the wall.

My plan was to trench out shallow trenches along the wall and into the brick. I would install FMC (1/2") which would come almost to the surface. I would then go back over with mortar, a skim coat of gypsum, and paint. Larger holes would be knocked out for boxes (do I need to use special in mortar boxes?).

Is there anything wrong with what I propose? Example things that could be wrong (partial list) a) Steel or Al FMC is not suitable. b) The depth is not suitable. c) I need to additionally derate the FMC and I don't know it. d) I'm not allow to make holes in the fire wall big enough for the boxes. e) ...

Am I going about this properly? What other things do I need to consider?

Thank you for your input, William

PS: NO. I do not want to use surface mount if I can avoid it.

[Goedjn]

Then use floor moounted outlets, or glue furring strips to the wall, run armored conduit behind it, and cover it with sheetrock. Don't mess with the partition wall.

[William.Deans]

Greetings,

Thank you for your post but I still don't have enough information to make a decision.

Don't mess with partition walls because it's a job you don't know how to handle or don't mess with them because it's not allowed? I am not looking for "another way" I am looking to attempt to perform the job in the manner specified safely and to code (building, electrical, and otherwise) if possible.

Hope to hear more, William

[Edwin Pawlowski]

Cutting into a structural firewall can be a violation of the code. I'd look for other way, either surface or floor mounted.

[Duane Bozarth]

Talk to local building permitting bunch--they'll tell you the exact skinny for both your specific structure and locale...

[Pop]

Besides, do I recall that this was a condo? There might be association requirements stating that you're not to touch that wall. That hurdle out of the way, any insurance or bank problems with it? THEN, I'd go to your local code enforcement and ask there. The best you could get here is experience, good as it may be, but NOT for your particular locale. NEC applies of course, but many local codes go beyond that.

JMO, but I think you need those items crossed off before you go too much further with the rest of the plan; they could make it all a minor or major detail.

HTH, PopS

[Goedjn]

Both. You almost certainly aren't allowed to mess with it, and that wall is not just a fire-barrier, it's part of the structure of the building that's designed to reduce noise, and resist vertical, earthquake, and wind loads. If you're having to ask about it here, you don't know enough about what it's doing and what effect your modifications will have on the various roles that wall is expected to play.

And for certain, nobody out on the internet is in a position to make a better guess.

If the first idea that's in your head is wedged so firmly that you can't get it out, then hire a professional to do the evaluation an subsequent work. Otherwise, let go of that idea, and come up with a new one, because hacking into the partition-wall with a masonry saw on your own hook is in no way a good idea.

--Goedjn

[William.Deans]

Greetings,

It is not a condo. It is a single family home. I own the houses on both sides of this house. There is not a bank problem because there is no mortgage on either home. There is no insurance problem because I don't carry insurance on the home (I am not required to and I don't). Yes, I do have an umbrella policy for my business.

Hope this helps, William

[William.Deans]

Greetings,

Why are you so sure that I am not allowed to mess with it? If the firewall is 10" thick and I make a 2 inch deep trough and later fill it in with mortar (and some outlet box holes) it won't change the structural integrity. It won't make it so the neighbors can hear through the wall. It won't change the fire rating to less than two sheets of 5/8" drywall which is used for partition walls between houses I have seen in the past. In short, I know it is probably safe. I am wondering about the code issues. Just because something is safe doesn't mean it complies with code. Of course local code could say ANYTHING but I am not asking if this violates local codes that no one here could know about. I am asking if it violates national codes or if (for some reason I cannot think of) there is in fact a safety concern.

Why are you so sure everyone on the Internet is dumb and cannot provide helpful advice? Why can't I tackle a project that I don't already know how to complete before I start? Plenty of people complete projects safely that they knew very little about before they started.

Update on materials used: I have found some PVC coated MC suitable for direct burial in concrete which has a smaller OD than 1/2" FMC so I have switched to using PVC coated MC with concrete tight connectors.

Hope this helps, William

[Edwin Pawlowski]

Rather that take advice from the people you are criticizing, ask your building inspector. He will know the codes, he will know if it is allowed. He may also know an easy way to do it.

[Duane Bozarth]

If you would the replies, it's not been stated unequivocally that you ANYTHING but I am not asking if this violates local codes that no one

For the reasons outlined above, no one here can unequivocally answer that question as posed, either. And, only your local code is of significance in judging whether your proposed modification(s) meet code, anyway, so why not just ask?

In this case, there's just not enough info to really provide a definitive answer remotely and it would be much simpler and more effective to just ask locally...

Nobody even came close to saying that you can't. You can find out the "how" for your particular situation easily locally...

[William.Deans]

Greetings,

When I ask a building inspector they generally just tell me a specific way to do it. The way "suggested" by the inspector way might not be the best way for my situation, might cost extra, might be extra work, might reduce the overall quality of the job but after they tell me "do it like this" then I am stuck. For instance, the inspector could say "why don't you just put up furring strips" and then, even if there were many other "legal" "better" options I would appear to be arguing with him to do otherwise. I want to come to the building inspector with a sound, code complete plan which works and doesn't have holes. The inspector will then approve my plan or site the local code I am violating and I will modify accordingly.

The only people I ever criticize here are naysayers. If I say, "How do I do XYZ" and someone says "Call a pro." or "You can't." but doesn't explain to give further depth of understanding then yes, I might criticize them. If someone says "you're too dumb to do that job" or "no one that uses the Internet could ever help" then I will definitely say something in response. I have successfully completed every job I have ever asked about on alt.home.repair. So yes, I probably can and will do that job. I might change my plans or methods based on input from alt.home.repair and elsewhere -- but the job is going to get done. (PS: I am very happy to know that I can't do XYZ if someone says why. I am especially happy to know if they site specifically why and give a reference. If someone JUST says "you can't" for all I know they are wrong and my knowledge of the situation has not been increased.)

There are many people on alt.home.repair who I have found to be very very helpful. A Mr. Miller and several others come to mind (don't want to list because I am sure I will leave someone good out). Some people are also hit and miss. I enjoy reading their thoughts even if I don't always agree with them. It is nice to get a second opinion. It is even nice to have a better understanding of common misconceptions.

Hope this helps, William

[William.Deans]

Greetings,

A) Of course no one can know what my local inspector will be thinking. I am therefore asking about breaking other-than-local electrical, fire, and building codes. B) Yes. In fact someone here did say that I didn't understand it and that I needed to hire a pro: "If you're having to ask about it here, you don't know enough about what it's doing and what effect your modifications will have on the various roles that wall is expected to play ... If the first idea that's in your head is wedged so firmly that you can't get it out, then hire a professional to do the evaluation an subsequent work. " C) If you need additional information, even a photo of a wall (for whatever help it may be) just ask. I have attempted to supply all relevant info without supplying fluff but if I left something out just ask. D) If it helps pretend local code doesn't exist where I am because I am the chief of an indian reservation and I set local code. However, I want my building insured by a national insurance company and I want to ensure that they are happy with the work because it doesn't violate well known national codes. If this pretend situation causes additional problems for you then just ignore it.

Hope this helps, William

[David Martel]

You don't know what you are doing. You don't know the local code. You won't hire a pro. You want free advice from people who may have little to no knowledge of your particular job, the local building code, et c. And you accuse the voice of sanity of being a naysayer. Use conduit.

Dave M.

[William.Deans]

Greetings,

You say "Use conduit" but there is no additional information as to why. Is there something wrong with PVC coated MC? The MC is MUCH easier to use than anything else because I only have to go as deep as the brick for most of the run. I will try to post some photos in the next couple hours.

William

[John Grabowski]

I understand the situation. Flexible metallic conduit cannot be embedded in masonry, but you can certainly use EMT. I suggest that you use 4" square x

1 1/2" deep electrical boxes with a quarter inch raised tile ring. Cutting back the brick to make a nice clean groove will be time consuming. I'm not sure of an easy way to do this except maybe with a hand grinder equipped with a masonry blade.

I've never used PVC coated MC cable embedded in concrete. It's definitely a good way to go and article 330.10(10) permits it.

John Grabowski

[William.Deans]

THANK YOU VERY MUCH JOHN.

I have some photos up. Please note that not all work will be exactly like in the photos but it should provide some basic idea. Also note that the PVC coated MC and staples will be completely covered by the mortar before the gypsum layer even though it is hard to tell because of lack of depth perception in the photos. Elsewhere in the house I WILL have to cut into the brick. I used a 3.5" deep concrete embeded device box for this outlet but I could easily switch to a more shallow box. I have about 40 of these things to do in total.

or

Thanks again John, William

[Duane Bozarth]

But how deep? I don't think you can just bury only thinly w/o protection to prevent the nail somebody tries to drive??? That's why the EMT was suggested, I think and why I'd ask a local...

[William.Deans]

Greetings,

I think the 1 1/4" rule is specifically for framing or wood and does not apply in the case of masonry but I could be wrong? If there is another rule covering minimum depth for this application I am not aware. If the walls were plaster I think I could plaster plain MC directly into them. I could always turn the trench into a "small, thin, section of plastered wall". Logically I don't see why I would need to embed the PVC coated MC deeper if the trench was filled with mortar? That doesn't mean there isn't a rule but I am not aware of it.

William

[Duane Bozarth]

That's why you need to ask locally...