Estimating outlets in CMU

archerycoach

Member
Location
KY
I am currently quoting a job where the customer has requested they be installed in the block wall. My experience with this while working in the field has been it's very time consuming and lots of varying factors. Does anyone have a labor hour number that has worked fairly well for them? I don't want to price myself out of the job, but then again I don't want to take a bath. :?
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Is it a new wall being constructed or an existing wall with the roof in place?

How will the wall be finished? Painted block? Stucco? Furring and drywall? Other?
 

archerycoach

Member
Location
KY
Is it a new wall being constructed or an existing wall with the roof in place?

How will the wall be finished? Painted block? Stucco? Furring and drywall? Other?
It is a brand new building, all walls new. Painted. no other finish. All exterior walls are also going to be slushed out every cell with rebar every 2'. Interior slushed every 4'
 

69gp

Senior Member
Location
MA
Each job is different. How many outlets, switches and other devices are going in the wall. How many wall need boxes in them. if it is only 10 to 15 boxes then I would just pre-assemble the box and length of EMT with a coupling on it. Cut enough stubs for going up the wall with a connector on it. Then just let the mason know where the boxes are going and he may add the stubs in as he goes up with the wall. Labor is maybe 10% more on a small job. On bigger jobs you may have a guy just watching the masons build the walls and need to add the stubs as the wall goes up. This can be time consuming but in the down time the journeyman can be building the boxes and stubs while the walls go up. Another 20% would be a fair assumption for this end.

One thing we do is used colored duct tape on boxes and the stub ups. Brown for lighting, red for fire alarm, orange for e-circuits, blue for data, pink for specialty and good old grey for receptacles. This works out great because its gives you a visual layout of the wall as it goes up and its easy to verify and take the guess work out what is installed.
 

GoldDigger

Moderator
Staff member
Is this a dwelling or commercial? If a dwelling you can run NM and avoid the mason chasing.

I don't know what "slushed" means.
It means poured full of mortar/concrete for additional strength.

In interior walls only one vertical column of blocks gets filled every four feet. And no rebar?
Outside walls are all filled, with rebar on two foot spacing.
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Ahhh. I'm familiar with the process. I never heard that term before. It must be a commercial building then. I've only worked on one building where all the exterior walls were filled with concrete. Good way to hurricane-proof a building. All the work there was surface mount EMT.
 

GoldDigger

Moderator
Staff member
Ahhh. I'm familiar with the process. I never heard that term before. It must be a commercial building then. I've only worked on one building where all the exterior walls were filled with concrete. Good way to hurricane-proof a building. All the work there was surface mount EMT.
OP's customer wants flush. If it is commercial, cost will vary enormously with wall type and position relative to rebar.
Clearly no easy way to pull pipe or NM to a box in a filled wall after construction.

In EU land they would probably saw cut a shallow channel and mortar the wires over. :)
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
OP's customer wants flush. If it is commercial, cost will vary enormously with wall type and position relative to rebar.
Clearly no easy way to pull pipe or NM to a box in a filled wall after construction.

In EU land they would probably saw cut a shallow channel and mortar the wires over. :)
I don't think NM is an option at all. It's not allowed embedded in concrete and no reason to use it if conduit is being run, THHN would be better.

Mason chasing 4x4 boxes & mudrings with PVC conduit is the way to go with this job. And yes, it will be labor intensive.
 

GoldDigger

Moderator
Staff member
I don't think NM is an option at all. It's not allowed embedded in concrete and no reason to use it if conduit is being run, THHN would be better.

Mason chasing 4x4 boxes & mudrings with PVC conduit is the way to go with this job. And yes, it will be labor intensive.
Question is whether loose (but supported....) in a void in a concrete block wall is considered "embedded" in concrete.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
Question is whether loose (but supported....) in a void in a concrete block wall is considered "embedded" in concrete.
Question answered!

(A) Type NM. Type NM cable shall be permitted as
follows:
(1) For both exposed and concealed work in normally dry
locations except as prohibited in 334.10(3)
(2) To be installed or fished in air voids in masonry block
or tile walls
 

archerycoach

Member
Location
KY
It means poured full of mortar/concrete for additional strength.

In interior walls only one vertical column of blocks gets filled every four feet. And no rebar?
Outside walls are all filled, with rebar on two foot spacing.

You are correct. It does have rebar every 4' as well..
 

Unbridled

Senior Member
Location
Tampa, Fl
I am currently quoting a job where the customer has requested they be installed in the block wall. My experience with this while working in the field has been it's very time consuming and lots of varying factors. Does anyone have a labor hour number that has worked fairly well for them? I don't want to price myself out of the job, but then again I don't want to take a bath. :?
My labor unit for a 20A Spec grade recpt. Fl. in Mason Wall is .81 / ea. and includes trim. You may want to bump it up for the EMT Stub up through the wall cavity, however many masons will install the box and conduit if you have it there while he is laying block. I typically cut the EMT in 3 FT sections so the mason doesn't have to lift his block too high over the EMT.
 

Mikros

Member
Location
Colorado
I'm doing a fire station right now that has all conduits/outlets concealed up to a minimum of 10' in the CMU areas. I'd plan on having a journeyman there the whole time the block is being laid and half again for a helper. Of course it depends on many variables, but in my case that would have worked out good. I didn't estimate this job but I have done a lot of estimating in the past. Add a good spaghetti pile too for scrap and mistake conduit. I did this building (the CMU) in EMT but if I were to do it again I'd look into PVC.
 
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