# CMU floor/roof



## KEPC (Jan 13, 2010)

Have you ever installed a CMU floor/roof?

I was told that it was a very economical way of installing a fire rated roof/floor? And that it was also well suit for acoustical purposes splitting the commercial area at the bottom and the residential at the top. 

There is a CMU joist (it looks similar to an I-beam) that is spread out 16OC. You place the CMU between the joists with the web facing its side and when you are finished you make some holes and fill the webs with grout. 

Any thoughts?


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## NJ Brickie (Jan 31, 2009)

Talked about alittle on here. 

http://www.contractortalk.com/f48/block-joists-70510/


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## concretemasonry (Dec 1, 2006)

That system has been used internationally for decades or years and is currently used.

Normally, high strength lightweight prestressed beam is used, but the U.S. copy used steel joists because they were available. I was on projects in VA under construction and on one the floor was rock-solid even before any grouting.

The result is a very rigid floor system with great sound separation and very low deflection or "bounce" because it is built without flexible materials like wood. It is also used for infill on sloped roofs.

I just received some photos of a similar system used on new up-scale 4 story block apartments in Accra, Ghana.


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## KEPC (Jan 13, 2010)

Thanks NJ Brickie and concretemasonry

I just purchased this warehouse. I am going to convert it into my shop. I plan on adding another floor. 

the first floor is going to be a work shop and If I plan on having my office up stairs, the ceiling will have to be fire rated. 

Would you happen to know the pricing of those pre stressed beams? The span is 19ft.


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