Thread: Poured concrete walls

Does anyone know what year builders started to put re-bar in the walls? Or is this something that is optional and how would know because you can't see it unless you actually did a cross-section of the foundation which isn't going to happen.

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For years it wasn't even required by codes. However engineers have speced in steel for a

r e a l

l o n g

time.

Ive seen it in 50's houses before but that's about as old as Ive seen. I'm pretty sure it was around a long time before that!

A Wayne said *a very long time* ...

In South Florida they were putting steel in masonry and concrete going back into the 1920s and 1930s, even earlier as I recall from some pre-1920's houses I inspected down there.

From what I've seen in my area (Oregon) it was rare in 40's and pretty much standard by the mid to late 50's. As the others said, it's been around for a long time but I think it took awhile to trickle down the residential construction.

Originally Posted by Bob Lynett

Does anyone know what year builders started to put re-bar in the walls? Or is this something that is optional and how would know because you can't see it unless you actually did a cross-section of the foundation which isn't going to happen.

Bob: You first refer to walls and then to the foundation. Which is it? Ground-penetrating radar will reveal the presence of rebar in concrete, but the price of the survey may be prohibitive.

Originally Posted by Bob Lynett

how would know because you can't see it unless you actually did a cross-section of the foundation which isn't going to happen.

There are several types of equipment available for that use, this is just one of them: Elcometer P120 Imp Rebar Locator

Originally Posted by Jerry Peck

There are several types of equipment available for that use, this is just one of them: Elcometer P120 Imp Rebar Locator

JP: Mine is cheaper.

Zircon Electronic Metal and Rebar Locator - Mfg# MT 6

Aaron,

But do those actually work and work well?

I've looked at them some in the magazines, but when that one is that price and almost everything else is in the $600-900 range I've always wondered if it actually worked well enough to be worth the price.

Kinda like buying a cheap infrared camera, sure, they work, but you can't see enough clarity to know what you are looking at, so why buy it?

Just curious.

Originally Posted by Jerry Peck

Aaron,

But do those actually work and work well?

I've looked at them some in the magazines, but when that one is that price and almost everything else is in the $600-900 range I've always wondered if it actually worked well enough to be worth the price.

Kinda like buying a cheap infrared camera, sure, they work, but you can't see enough clarity to know what you are looking at, so why buy it?

Just curious.

JP: And now we are back to my original post. Ground-penetrating radar will tell you a lot more.

Originally Posted by A.D. Miller

JP: And now we are back to my original post. Ground-penetrating radar will tell you a lot more.

Or take an infrared photo of the wall, then simply energize the steel, let it heat up just a little bit, won't take much, then take another infrared photo of the wall ... the steel will show up as warmer.

'Course, there is that risk of the energized steel causing a problem ...

'Course, there is that risk of the energized steel causing a problem ...

JP: And the demo required to find it.

Originally Posted by A.D. Miller

JP: And the demo required to find it.

Aaron,

Shouldn't be any demo work, just potential for electrical shocks, so extreme precautions would need to be taken (no one else near the house, etc., during the time it is energized), as all you are doing is *SLIGHTLY* heating the steel, even if it just heats up one degree, any decent infrared cameras can detect <0.1 degree C difference. The one I used to have was rated as such, I believe the actual number, which varied from sensor to sensor (forgot the name for them) on the array, was something like 0.08 degrees C average on the camera I had, but it's been a while since I sold it, much less since I bought it.

Would love to still have it, but oh well.

Maybe I'm missing something, but if you can find the steel to heat it up, to find it........uuuhhhhhhh, maybe you don't need to heat it up.

Originally Posted by Jack Feldmann

Maybe I'm missing something, but if you can find the steel to heat it up, to find it........uuuhhhhhhh, maybe you don't need to heat it up.

Jack,

Just take the concrete encased electrode conductor, disconnect it from the grounding electrode system, put a few amps through the steel (as many as needed to heat it up slightly) and those heated up areas will show in the infrared, and ... (not that I would recommend doing this, but ... it could probably be done) ...

... no, you do not need to know where the steel is to be able to heat it up.

Is that what you were missing? The concrete encased electrode conductor attachment point?

"Head slap moment"

Bob,

Back to your original question: Speaking as a former residential concrete contractor, from Wisconsin, placing rebar in poured residential basement walls has always been an "option". Some concrete contractors do, most don't. Some home builders/general contractors specify it, most don't, unless of course the concrete contractor puts it in for his own peace of mind, and......most important.....at no extra cost to the general contractor. Generally, only high-end residential single family and multi-family projects where an architect/engineer actually specifies rebar placement, size and spacing, is it used. There are no codes currently specifying the use of rebar in residential basements.

Originally Posted by Michael Bower

Bob,

Back to your original question: Speaking as a former residential concrete contractor, from Wisconsin, placing rebar in poured residential basement walls has always been an "option". Some concrete contractors do, most don't. Some home builders/general contractors specify it, most don't, unless of course the concrete contractor puts it in for his own peace of mind, and......most important.....at no extra cost to the general contractor. Generally, only high-end residential single family and multi-family projects where an architect/engineer actually specifies rebar placement, size and spacing, is it used. There are no codes currently specifying the use of rebar in residential basements.

Unless I am reading the 2006 IRC incorrectly, if you are in seismic zones D0, D1, or D2, and granted that means this does not apply to everyone, that concrete foundation walls shown as PC (plain concrete) is required to have not less than #4 bars not greater than 48" on center.