Soundproofing between floors

[faultymechanics]

Hey all,

Planning to add some soundproofing between my crawlspace ceiling and the floors of my home's nursery and master bedroom directly above.

The dehumidifier and sump discharge are right below the Nursery and Master in the crawlspace. The humming from the dehumidifer and sudden thump and water rushing sound of the sump pump can be a bit annoying and I'm trying to plan for the future child staying in that nursery.

Any tips or suggestions? I'm thinking Rockwool Rockboard between the joists but I want to make sure I'm going the right direction. This is a very doable job for me but it isn't cheap to get the materials. I also don't want to cause any ventilation or humidity issues in the house because of adding insulation to this crawlspace ceiling.

Would love to hear any and all input, especially if you have done something similar. I believe the dehumidifier puts out low frequency noise whereas the sump is a lower and sudden noise.

 

[saberbass]

I built a guitar jam room in my basement . My band plays pretty / very loud. I used rock wool between the joists and put double drywall with green glue ( a sound absorber) between the sheets. It helped a lot with the upper frequencies and made the rest of the house livable while we play. Instead of drywall I would think you could use double sheets of osb with green glue, and the rockwool.

 

[Ashful]

Separate and staggered ceiling and floor joists are often used, so there's no acoustic bridge between ceiling and floor.

For insulation, most find a system containing both low and high density materials is key for rejecting the full spectrum of sounds that may carry thru. It can be looked at as both reflection and absorption, but truly it's more likely one in the lower part of the band, and another in the higher part. Translation, maybe place spun fiberglass batts atop insulation board, for more full-spectrum performance.

If the noise source is of fixed frequency, or narrow-spectrum, you could favor materials that only absorb or reflect that narrow part of the spectrum. By doing this, you can get better performance, if you know the material system to target for that range of frequencies.

Of course, this is all theory, and related to what I do for a living. But you're working at Hz and low-kHz... I work at GHz. So, unfortunately I have no specific material systems to recommend, only theory.

 

[faultymechanics]

Separate and staggered ceiling and floor joists are often used, so there's no acoustic bridge between ceiling and floor.

For insulation, most find a system containing both low and high density materials is key for rejecting the full spectrum of sounds that may carry thru. It can be looked at as both reflection and absorption, but truly it's more likely one in the lower part of the band, and another in the higher part. Translation, maybe place spun fiberglass batts atop insulation board, for more full-spectrum performance.

If the noise source is of fixed frequency, or narrow-spectrum, you could favor materials that only absorb or reflect that narrow part of the spectrum. By doing this, you can get better performance, if you know the material system to target for that range of frequencies.

Of course, this is all theory, and related to what I do for a living. But you're working at Hz and low-kHz... I work at GHz. So, unfortunately I have no specific material systems to recommend, only theory.

Does insulation board actually offer sound dampening? I support I could do an insulation board and rockwool after.

 

[EbS-P]

Thinking outside the box but could you add a smaller lower flow pump that could operate with less noise (and probably less capacity) set it’s float to come one before the older bigger pump? If it couldn’t handle the capacity the bigger pump would kick on? Just a thought.

If you need to insulate go that route. But adding a smaller quieter pump seems easy enough on the surface.

 

[Ashful]

Does insulation board actually offer sound dampening? I support I could do an insulation board and rockwool after.

A house I grew up in wore a layer of heavy insulation board between siding and sheathing installed early 1950’s, and it was an excellent sound damper. My memory tells me it was some type of fiberlglass product, 3/4” thick, but I don’t know the proper name for it. I don’t know about similar alternatives made today, other than to say a variety of density, as well as alternating reflective barriers with absorptive layers, is generally your best bet. I wouldn’t be surprised if acoustic ceiling tiles backed with spun fiberglass outdoes most alternatives.

 

[torpesco]

This is kind of similar to something I’ve been wondering about in my home. In the early stages of a reno with too much muddling my brain, an HVAC guy pushed me to go with a heat pump water heater. I love the low energy use. I don’t love the noise. The utility closet is in the center of our main floor (slab on grade) home.

Aside from ceiling and walls, I want to see if there’s something I can do to reduce the noise going through the dual bifold closet doors. (Actually, I may try doing only the doors to start.)

I know it won’t be perfect. I’m just hoping to take the edge off the noise.

Has anyone here had any experience with reducing noise travelling through or around doors?

 

[EbS-P]

This is kind of similar to something I’ve been wondering about in my home. In the early stages of a reno with too much muddling my brain, an HVAC guy pushed me to go with a heat pump water heater. I love the low energy use. I don’t love the noise. The utility closet is in the center of our main floor (slab on grade) home.

Aside from ceiling and walls, I want to see if there’s something I can do to reduce the noise going through the dual bifold closet doors. (Actually, I may try doing only the doors to start.)

I know it won’t be perfect. I’m just hoping to take the edge off the noise.

Has anyone here had any experience with reducing noise travelling through or around doors?

I think adding ducting with silencers can help with a fan noise. How big of an area are you circulating the air through? At least with the ducting you could do a better job of sound insulation around the unit.

I ducted my intake above the doors. The exhaust just exits pointed down. If I used an 8” silencer on the exhaust duct it would be quieter.

I had a thread on ducting mine here.

Heat pump water heater ducting question?

Hi am having an 80 gallon heat pump water heater installed in the basement. It will be in a mechanical space that is 15’x2’. One long and one short wall are crawl space walls while the other long wall is half bathroom wall and half back of closet. The Bedroom room then is about 15x15...

www.hearth.com

 

[torpesco]

I think adding ducting with silencers can help with a fan noise. How big of an area are you circulating the air through? At least with the ducting you could do a better job of sound insulation around the unit.

I ducted my intake above the doors. The exhaust just exits pointed down. If I used an 8” silencer on the exhaust duct it would be quieter.

Shoot... now I feel like I'm taking the thread sideways, sorry. (Ducting doesn't apply to sump pump noise.)

I'd been wondering about ducting for a different reason, but now there's extra motivation - the hope that it'll help cut the noise a bit. I'd be inclined to go straight to using a silencer hose. I'll go into more detail in that other thread, where it seems more appropriate.