huangyhg

noises in floor system
at one of the residential homes i designed, tji floor joists were installed with top flange hangers welded to a steel beam (no nailer used). all components are in accordance with the manufacturers recommendations, but we still have nasty noises, like metal on metal (it is not because of shiners).
any ideas about what causes this and how to fix it would be greatly appreciated.
can we get some details of the joist to steel beam connection as i am not familiar with this type of detail, i don't even know what a tj1 is, but i am australian.
also is possible to get a bit more of an idea of the type of noise, squeak, banging ect???

when in doubt, just take the next small step.

generally, the higher the density of a material, the greater the sound transmission. you have steel supports for the truss joists, so any sound that is carried by the joints goes to the steel, unmitigated. depending on the configuration of your connections, this can actually be amplified through a process called flanking.
this process is exacerbated by hard floor finishes such as tile. most building codes in the us limit the sound transmission in wall-to-wall and floor-to-ceiling conditions. the construction method you described does little to mitigate such sound transmission.
you will need to either insulate the sound or isolate the sound. insulation methods are obvious...batt, sprayed, or foamed. isolation is a little less obvious. rubber washers between the hangers and the beam would be one method of isolation...not great, but workable and provides some sound transmission reduction. another is to coat all the hangers with a resilient coating (rubberized, urethane, etc.).
filling the cavity with insulation will help. placing a sound isolation membrane on the floor above will help also.
do not forget thermal adjustement. whilst studying architecture in madrid i lived in a college (colegio mayor universitario, cmu heh) where transverse beams cantilevered on 2 colums at every frame and floor. according to much practice of the era stabilization likely was at the core of the building, maybe end of wings as well, and the transverse beams were (it seems) quite free to acommodate movement upon their seats at the columns. it produced nice and neat (non intimidating, it was obviously stiff enough) crackles and shrieks. it also was nice bouncing amidst the main beams, heh.
rheim,
firstly, although i think i have heard the term, i can't re
hokie -
a "shiner" is when you have a nail showing above the plywood, that is slipping causing squeaking.
it got the term from reflecting or shining due to wear from traffic from protruding above the surface of the plywood sheathing.
this is not the australian version of a black eye...
confusing enough?
mike mccann
mmc engineering
thanks, mike. we have squeaky floors over here, too.
a "shiner" is also a nail that missed its mark...didn't go into the sheathing support, so the sheathing at that point is not attached...causes squeaking.
that's why its a good idea to both nail and glue floor sheathing in place.
true too. thanks ron.
mike mccann
mmc engineering
2nd mike's statement about shiners.
is the nailing of the steel hangers to the side of the tji slipping up and down on the hanger?
mike mccann
mmc engineering

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