[alexlacelle]

I'm currently renovating my basement and am in the process of soundproofing the basement ceiling. My joists are 24'' on center and I just picked up some Roxul Safe n Sound which is made for 24'' centers. The batts are about 3 inches thick, and the problem I'm having is that when I put them up they are sagging in the middle. I'm not sure if this is normal or not

Assuming this shouldn't be happening, I thought about adding some strapping to ensure they don't ever call out completely, especially since I'll only be installing a drop ceiling. Other than that the other option I thought of was to use the Roxul insulation batts that are 24'' on center as I'm thinking these won't sag as much since they're thicker.

Any suggestions?

 

[TrailerParadise]

ive been told that with Roxul you are supposed to use a batt that is slightly wider than the opening, and slightly press in the edges to install it, because that makes it hold itself up. im no pro, but it makes sense in my head.

 

[alexlacelle]

ive been told that with Roxul you are supposed to use a batt that is slightly wider than the opening, and slightly press in the edges to install it, because that makes it hold itself up. im no pro, but it makes sense in my head.

Yes that's what I have here. The batt is slightly wider, however because the batts are 24 inches wide they're sagging

 

[Fix'n it]

24" oc, what size are the joists ? what is the room above ?

anyway. don't expect much soundproofing whit that 3".

 

[alexlacelle]

24" oc, what size are the joists ? what is the room above ?

anyway. don't expect much soundproofing whit that 3".

The room above is a living room upstairs. I'll have to measure a joist. You say that 3'' won't offer much soundproofing, what would be better?

 

[joecaption]

No insulation hangers?

 

[alexlacelle]

I ended up putting it in today with strapping. I had a ton of 3 inch wide pine that I took down during the demo that I saved for this. It worked pretty well. Overall I'm happy I soundproofed. Even at 3 inches it made a noticeable difference.

Thanks!

 

[Gary in WA]

3" is fine; figs. 12, 13; http://www.certainteed.com/resources/Guide for Residential Sound Control.pdf

Roxul is even better, twice as dense as most f.g.; http://www.roxul.com/files/RX-NA-EN/pdf/SafenSound.pdf

Did you use the Safe-n-sound, or comfort-batt; http://www.roxul.com/residential/residential+technical+data

Quieter and greener; http://www.buildinggreen.com/auth/a...ial-and-Commercial-Insulation/?&printable=yes

Gary

 

[Fix'n it]

The room above is a living room upstairs. I'll have to measure a joist. You say that 3'' won't offer much soundproofing, what would be better?

I ended up putting it in today with strapping. I had a ton of 3 inch wide pine that I took down during the demo that I saved for this. It worked pretty well. Overall I'm happy I soundproofed. Even at 3 inches it made a noticeable difference.

sure, 3" will help. but it will not eliminate all sound transfer. if it were me, i would at least fill the cavity. so if you had a 8" joist, put in 8" of roxul.

i used to live in a modern condo. it had flexicore ceilings http://www.undergroundhomes.com/flexicore.htm
with a layer on concrete on top. i could still hear some things coming from above.

 

[alexlacelle]

3" is fine; figs. 12, 13; http://www.certainteed.com/resources/Guide for Residential Sound Control.pdf

Roxul is even better, twice as dense as most f.g.; http://www.roxul.com/files/RX-NA-EN/pdf/SafenSound.pdf

Did you use the Safe-n-sound, or comfort-batt; http://www.roxul.com/residential/residential+technical+data

Quieter and greener; http://www.buildinggreen.com/auth/a...ial-and-Commercial-Insulation/?&printable=yes

Gary

I used the Roxul Safe-n-sound. I thought about doubling it up but the research I did suggested it wasn't worth the extra money.

 

[Gary in WA]

Good you did not double it up; "A significant advantage is made by adding higher density insulation in addition to the improvements that can be achieved with other
sound improving methods such as resilient channels, air space depth, or additional layers of wall board.Graph 1, #7: https://docs.google.com/viewer?a=v&q=cache:4Xm4V72zcqYJ:www.certainteed.com/resources/30-49-109%2520Insulation%2520Guide.pdf+cover+paper+faced+fiberglass+insulation+in+garage+rafters&hl=en&gl=us&pid=bl&srcid=ADGEESgVxzckgJMdEIaG-b7SkEtA3-0aJrAttHdUxTlBRl6AqKdFTeMaW67MjDOgUO0O1g9uEObUAFFkz0B9gxoV3iBmiPTVpjC4lZCec2PTJfyJPMcXu0Ixj_cLOm2Vq35p5WQFwC-N&sig=AHIEtbTZDXWh2g1LzATpsMKTgMsl7TruSQ

Roxul recommends the one you used (2.5# density) over the Comfort batt (>2# density) also. The only thing to do better would be the resilient channels rather than wood strapping...

Gary

 

[alexlacelle]

Good you did not double it up; "A significant advantage is made by adding higher density insulation in addition to the improvements that can be achieved with other
sound improving methods such as resilient channels, air space depth, or additional layers of wall board.Graph 1, #7: https://docs.google.com/viewer?a=v&...QFwC-N&sig=AHIEtbTZDXWh2g1LzATpsMKTgMsl7TruSQ

Roxul recommends the one you used (2.5# density) over the Comfort batt (>2# density) also. The only thing to do better would be the resilient channels rather than wood strapping...

Gary

I'm actually going with a drop ceiling in the space. I ordered the Armstrong 5/8 tiles that say they absorb 60% of noise. Seems a little high for a drop ceiling tile but we'll see. Between those and the Safe-n-sound the sound should be half decently stopped I'm hopping.