Mezzanine Joist Space Directions?
Mezzanine Joist Space Directions?
(OP)
Hello.
I'm just working on a complex project right now with a weird shape for the building. I was wanting to span one section of jsts one way and another span perp to them. My concern is we are using 1-1/2" steel jst deck, and I don't know exactly what happens to connect the different directional roof decks together.
Is this even possible and if so are there any problems associated with this type of construction?
Thanks
Matt
I'm just working on a complex project right now with a weird shape for the building. I was wanting to span one section of jsts one way and another span perp to them. My concern is we are using 1-1/2" steel jst deck, and I don't know exactly what happens to connect the different directional roof decks together.
Is this even possible and if so are there any problems associated with this type of construction?
Thanks
Matt






RE: Mezzanine Joist Space Directions?
RE: Mezzanine Joist Space Directions?
RE: Mezzanine Joist Space Directions?
RE: Mezzanine Joist Space Directions?
If the deck change is perpendicular to the slope of the roof, then you can't use an isolation joint. In that case you must use a concealed "slip" joint that will attenuate the strains in both directions. This is for a built-up roof system or a fully adhered single ply roof system. For mechanically fastened single ply systems, the direction change is not a big issue.
RE: Mezzanine Joist Space Directions?
RE: Mezzanine Joist Space Directions?
You would think that theoretically there wouldn't be much differential movement since both edges are fully supported and it isn't a structural expansion joint. But there's enough movement to split a roof membrane and if the insulation is installed across this joint, enough movement to break the insulation. I've seen lots of them here in Florida.
We had to design around a similar occurrence on a General Mail Facility in Atlanta.
RE: Mezzanine Joist Space Directions?
Regards,
Lutfi
RE: Mezzanine Joist Space Directions?
Dik
RE: Mezzanine Joist Space Directions?
I use that detail as well. It depends on the situation.
Regards,
Lutfi
RE: Mezzanine Joist Space Directions?
Matt