OK, I now have a request to sound dampen between floors in a motel that was built in about 1970.
The construction method is 6×8 exposed beams(4′ on center) front to back of the first floor ceilings,with 2x tongue and groove over that(exposed as well) and then pad and carpet in the second floor rooms.
As you can imagine, the sound transmission from up to down is considerable and annoying to the new owners. They like the look of the exposed wood ceilings,but are willing to make a change for quieter rooms. They would like to leave a little of the beams exposed, if possible.
So I begin to think about a framed fur-down between beams to place fiberglass batts and also homasote and then finish between beams with drywall.(Thought about ceiling tiles,but I think they would be prone to damage as the reach to the beams is about 7’4″). Of course I am concerned that even if I could come up with a method of soundproofing between the beams, that the beams themselves would transmit sound and make the other efforts ineffective.
Your thoughts??
jw
what the heck
was I thinking?
Replies
We had to do this in a 7K sq. ft. custom home ... actually, it was a 1500 sq. ft. ranch with a 5500 sq. ft. addition, at about $275 a sq. ft. The ranch kind of got lost in there. Architect drew T&G over beams, we did it, they didn't like it. We laid a 2X nailer on to the sides of the beams and laid in batts, then finished w/ beaded ply paneling. The result was pretty effective. Homasote & drywwall over batts, or better yet over foam, would be much better. If I did it again, I would spray in foam, as I think (personal opinion) that the physical bond of the foam to the existing structure dampens the diaphragm effect of sound energy striking the floor. Will the beams still transmit sound? Probably, but whaddaya do? If they like the beams and want to retain them, I think they will be happy with the improvement you do attain.
5500 sp to a 1500 existing, almost seems like they should have just started from scratch.
Instead of constructing a furdown and using S.A.B.'s-(fiberglass sound attenuation blankets), just create an acoustical cavity using 7/8" resiliant channel screwed directly to existing ceiling between the beams. Then screw a layer of 5/8" Fire Code drywall directly to the resiliant channel (also called hat channel).
By running your hat channel perpindicular to the joists or beams in the ceiling there is very little direct sound transmision and the 7/8" cavity created by the hat channel being sandwiched between the existing ceiling and the new layer of drywall is called an acoustical cavity for good reason. It has a great S.T.C. or sound transmission coeficient. The hat channel should be layed out on 16" centers, screwed on with 1-7/8" sharp point medium thread drywall screws (screws spaced aprox. every 8-10". You'll also need to run the channel around the edges or borders of the ceiling area being covered to give you something to screw the drywall to so it won't sag. You can also use small wood nailers along the side of the beams as nailers ect.. Use 1-1/4" sharp point medium thread drywall screws to attach the 5/8 F.C. drywall to the channel. Then when the drywall is up, sound calk the joints where the drywall meets the beams.
If you need more specifications on the properties or performance of this system (fire code,acoustical,ect.) you can find them in either the Republic (Gold Bond), or U.S.G. drywall installers handbook available at most building supply stores.
Labor wise this takes about twice as long to do, compaired to just adding a layer of drywall directly to the existing ceiling.
Done this a bunch. Works good. Commercial Interior Finish Out-Dallas Tx.
BEMW & cork--
Thanks for the input. I have the opportunity on this project to do one ceiling to test for effectiveness and then evaluate and adapt method for next room.So I may become my own testing lab.At this point, I think I will do the first room as per cork's recommendation,and see how it performs...anyone know where I could get some affordable electronic equipment to read the before and after sound levels?
Thanks again, jwwhat the heck was I thinking?
The solutions mentioned should work to some degree. As you suspected, the beams themselves will continue to transmit 10-20% of the sound you are trying to block.
In my opinion, the best solution for the family would be to focus on the upper surface of the floor and not the underside. Get the thickest carpet pad you can find (suppliers may even have special rubber mat-like products specifically for this purpose) and then cover it with a good heavy knap carpet. This should dampen as much of the sound transmission any low-tech, potentially schlocky-looking (no offence, but that's not how the ceiling was designed to look, after all) solution would.
As a bonus, the capet will be a joy to walk on, less messy and intrusive to install, and probably cheaper for the homeowner (though not good $$$ for you, unless you lay carpet :-)
P.S. as a professional music guy, I'm not a novice when it comes to acoustics - though hardly a pro in this specific area.
Radio suck has DB meters. Not to bad in price how accurate they are can't say.