Filling in holes vs. embedding romex

[peter d]

A smarter design would be to have 1-1/2" deep furring on the CMU to allow for a box and plaster ring.
I have always hated that we have to bust out the CMU to install boxes for receptacles or switches.
By not breaking out the CMU, the fire rating is not compromised.

The Floridian homes have regular 5/8" furring on the wall.

 

[peter d]

I'm pretty familiar with this peculiar Floridian wiring method as my parents are buying a new house in southwest Florida (Charlotte county) and I was able to see several new homes in their development in the rough stage. Anyway, the EC filled all the voids behind the boxes with spray foam, not mortar.

To the Florida guys, how do you make all the holes behind the boxes? It looked like a concrete saw or angle grinder was used, but I couldn't be certain.

I stand corrected, it's actually Sarasota County but it's only a few miles from the county line, hence my confusion. As if anyone cares.

 

[kwired]

but I'm guessing playing that card doesn't make any friends at the building department.

Playing the "Because I said so" card doesn't make any friends with the contractors either.

If you respect them and the rules they are there to enforce, you should be able to expect similar respect in return including following their own policies.

 

[donaldelectrician]

I'm pretty familiar with this peculiar Floridian wiring method as my parents are buying a new house in southwest Florida (Charlotte county) and I was able to see several new homes in their development in the rough stage. Anyway, the EC filled all the voids behind the boxes with spray foam, not mortar.

To the Florida guys, how do you make all the holes behind the boxes? It looked like a concrete saw or angle grinder was used, but I couldn't be certain.

Peter D.... We use the small grinder with a diamond crusted concrete masonry cutter blade .




Don

 

[bphgravity]

I stand corrected, it's actually Sarasota County but it's only a few miles from the county line, hence my confusion. As if anyone cares.

Sounds like it may be in the City of North Port, the jurisdiction I worked for 10-years and left as it's BO...

 

[mwm1752]

My inspector made it clear that, in his opinion, the holes could not be filled with spray foam - stating "that stuff burns". My electrician also said he used spray foam once and the AHJ forced him to remove it.

So, Is the inspector not allowing foam insulation in walls & ceiling. The green team will be awfully upset -- It is true there is a heat chemical reaction which causes heat in the initial install but layers up to 3"-4" should be acceptable as not to destroy the composition of plastic,

 

[kwired]

Great thought, but the Florida Building Code doesn't require a fire rating in my particular situation.

Flammability shouldn't matter then.

Inspection passed. I asked the inspector about the mortaring of the boxes and he responded that it wasn't his "trade" - so that was a great clue as to the purpose of the mortar. Researched the Energy Code and I'm fairly confident now that it has to do with sealing the thermal envelope. Therefore my solution of mortaring in (and sealing) behind the boxes - and avoiding embedment of the Romex - should suffice. I suppose I'll find out during the framing/insulation inspection.

Thanks for all the input.

Anything that seals out infiltration is acceptable for this purpose.

Now if you need to seal out infiltration as well as have a fire rating - you need a sealant rated for both purposes.

An electrical inspector shouldn't care, unless he is a "multi hat" inspector and also inspects other building codes, as long as whatever is used is compatible with the wiring method used.

Now if the inspector knows you will be in violation of other codes and wants to warn you - that is just him being friendly about it, it is another inspector for another code that is the one who will condemn it.

 

[peter d]

Sounds like it may be in the City of North Port, the jurisdiction I worked for 10-years and left as it's BO...

Nope.

 

[iwire]

A smarter design would be to have 1-1/2" deep furring on the CMU to allow for a box and plaster ring.
I have always hated that we have to bust out the CMU to install boxes for receptacles or switches.
By not breaking out the CMU, the fire rating is not compromised.

This is strictly an electricians view point.

If I was paying for the construction it would be furring strips, I would not permently give up sq. footage just to make life easier for the trades.

 

[kwired]

This is strictly an electricians view point.

If I was paying for the construction it would be furring strips, I would not permently give up sq. footage just to make life easier for the trades.

There is a balance between what little square footage is given up vs. how much extra labor may be needed if you don't do it so it is easier for some of the trades.

I did a kitchen remodel last winter - they did not want to tear down the existing ceiling (plaster and wood lath) but had no problems with me cutting holes as needed to fish cables (attic crawl space was too small to access) because they were going to put furring strips up and drywall the ceiling anyway. By the time I was done cutting holes, making a big mess, then later needed to cut more holes and make a big mess again I think we would have been better off just ripping the whole thing down. I certainly spent a lot more time on that rough in then if it would have been completely removed before hand. The walls had been stripped they just though they would lose too much heat or something if they removed the ceiling.

 

[tkb]

This is strictly an electricians view point.

Isn't that the only view that counts? :thumbsup:

 

[peter d]

This is strictly an electricians view point.

If I was paying for the construction it would be furring strips, I would not permently give up sq. footage just to make life easier for the trades.

In Florida, they certainly do not give up the space and I have pictures to prove it.

 

[iwire]

There is a balance between what little square footage is given up vs. how much extra labor may be needed if you don't do it so it is easier for some of the trades.

Extra labor once or lose sq ft forever.

Do what you want, I know what I would do if I was paying the bills.

 

[kwired]

Extra labor once or lose sq ft forever.

Do what you want, I know what I would do if I was paying the bills.

You don't do residential work, when it comes to homeowners they only see dollar signs on such projects.

Besides if you have a 10 x 10 room and furred all sides with 3/4 strips and 1/2 drywall you reduce it from 100 square feet to 95.88.

If you went with 1-1/2 strips instead so it made it easier for the electrician you reduce it to 93.44 square feet.

That is a difference of only 2.44 square feet - and is if you are doing all 4 walls.

I run into this a lot in basements where we are only doing the exterior wall, thermal insulation is really needed anyway so an extra 3/4 inch of insulation is probably worth the little square footage that is lost.

Take same 10x10 room but only fur out one wall and you reduce square footage to 98.96 with 3/4 strips or 98.33 with 1.5 strips - only a difference of .63 square feet. An appraiser will not even notice any difference here when setting a value on the home, that room is still 100 square feet in their calculations.

 

[iwire]

You don't do residential work, when it comes to homeowners they only see dollar signs on such projects.

Besides if you have a 10 x 10 room and furred all sides with 3/4 strips and 1/2 drywall you reduce it from 100 square feet to 95.88.

If you went with 1-1/2 strips instead so it made it easier for the electrician you reduce it to 93.44 square feet.

That is a difference of only 2.44 square feet - and is if you are doing all 4 walls.

I run into this a lot in basements where we are only doing the exterior wall, thermal insulation is really needed anyway so an extra 3/4 inch of insulation is probably worth the little square footage that is lost.

Take same 10x10 room but only fur out one wall and you reduce square footage to 98.96 with 3/4 strips or 98.33 with 1.5 strips - only a difference of .63 square feet. An appraiser will not even notice any difference here when setting a value on the home, that room is still 100 square feet in their calculations.

I don't do residential so I do not understand. What a load of horse hockey..


First off this thread was not about a basement, it was about an entire dwelling unit with CMU walls

Secondly using larger firing strips adds costs for more material and if you make it a stud wall that adds labor for the carpenters.

Like I said, if I was paying the bills I know what I would do, it seems you know what you would do too.

The fact we see thin firing strips used again and again making more work for the electricians seems to prove my point. Permanent space is more valuable than making life easy for the EC.

 

[kwired]

I don't do residential so I do not understand. What a load of horse hockey..


First off this thread was not about a basement, it was about an entire dwelling unit with CMU walls

Secondly using larger firing strips adds costs for more material and if you make it a stud wall that adds labor for the carpenters.

Like I said, if I was paying the bills I know what I would do, it seems you know what you would do too.

The fact we see thin firing strips used again and again making more work for the electricians seems to prove my point. Permanent space is more valuable than making life easy for the EC.

Well then my next suggestion is if they want cheap and no lost floor space - to use surface mounted raceways. I've even done that in older homes or rentals where they want electrical upgraded but don't want to spend a lot. In old houses on second floors with knee walls that have little attic space and finished ceilings on floor below leaving you with little space to easily fish NM cable to where you would like to get to, run EMT just above baseboards and you are through there in little time and didn't have to open any walls and have them repaired when done. After furnishing the room a lot of it isn't even noticed anyway, and blends in even better if they paint it same color as the walls.