Real world soundproofing experiences
As my framing nears it’s end I’m still undecided on what level of soundproofing to adopt in my compact 980sq ft home. The layout is attached and the focus is to isolate the bedrooms from the living space so that normal daily life doesn’t effect the quietness/sleep we love. There’s a few discussions here but I didn’t really get a sense of real life experience with different assemblies, and else where on the internet I could only find discussion focused on home theatres or soundproofing between floors. Discussions of STC ratings and frequency absorption characteristics don’t really help me figure out what level to settle on.
What I have decided is that I will weather strip and use door sweeps on solid core bedroom doors and air seal the green and yellow highlighted walls. The yellow wall will receive double 5/8 drywall on the entry wall side with sound dampening compound in between and cavity insulation.
The walls in green, I’m not sure if I go with double 5/8 and sound dampening compound, or if it’s worth going with full sound isolation clips plus single or double 5/8. The latter was the suggestion when I contacted a soundproofing material supplier. One duct will penetrate the wall from the ensuite to the kitchen/living area and at the moment I don’t plan on doing anything with the floor so I’m wondering if sound clips is overkill and will be short circuited by either of these.
I’m leaning towards the level 2 solution shown here
https://www.soundproofingcompany.com/soundproofing-solutions/soundproofing-walls
Any practical insight is appreciated.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
I went the cheap route and used fiberglass batts between studs, sliced the (non-loadbearing partition studs) vertically except the bottom and top 1.5', to reduce sound going through the studs from room to room, used two layers of standard 1/2" drywall (top layer mostly glued, fewer screws), caulked the bottom plate, and avoided having electrical outlets in the same stud bay (facing the other room). Did use sold core pine doors, and the carpet (bedrooms) reached the bottom of the door, but didn't use weatherstripping (but would recommend it). The doors did not face an open noisy room, they were facing a corridor upstairs. That's one problem you have, with the doors adjoining the kitchen and living room.
Loud music played in one bedroom could only be heard softly in the adjoining room. One day we were in one bedroom with the door closed, and when we opened it, realized our son had been crying loudly in the other bedroom (other door also closed). Another time, I had my brother go into one bedroom while I listened in the other bedroom, and told him to yell loudly at the intervening wall, and pound the wall. I could hear very little noise, not enough to wake someone. Having lived in noisy apartments in LA getting sleep interrupted often, I was very amazed at how little cost can result in such effective soundproofing!
There's a lot better noise control products available nowadays, including wrapping electrical outlets. But I suspect your biggest source of interior noise will be through the doors. Solid core weatherstripped is a good idea. Carpet in bedrooms might help too, reduce reverberations within the room? Good that your beds are offset from the doors, so noise through the doorways can't travel directly to someone sleeping. I'd consider doing some work on the wall between bedroom 2 and the adjoining bathroom. Use cheap solutions there?
I'd also recommend a sound-generating machine so white noise, rain noise or ocean sounds can mask other sounds from the other rooms or from outdoors. That has helped me in noisy areas. Triple pane windows help a lot too (assuming you are in a cold winter climate needing the extra insulation too).
You're right, I should do something with that bathroom. I've always found it strange since moving to North America how easy it is to hear bathroom activities in most houses! I grew up in a brick house.
This might help.
https://www.youtube.com/watch?v=GLjhrXFo0Kw
I'm not a sound expert but I've spent the last year soundproofing the small apartment (800 sf)I built into a large warehouse -garage. I started building with no idea of controlling sound until one day my brother showed up and started playing music in his part of the structure. I could hear everything even plain conversations. I didn't want to live with those interruptions in my life so I started researching everywhere on how to soundproof the area.
Your right the info thats available comes from home theater designers or recording studio builders or someone trying to sell you their products. Since you haven't started building yet I'd recommend taking the time before you start to educate yourself on the various strategies because its a lot more work , a lot more wasted interior space and cost to implement some strategies after building has begun.
One thing I can tell you from my experience is if you only address the walls between where the noise comes from and you ,you'll be disappointed. You are only as good as your weakest link when trying to control sound. If you want the bedroom or any room quiet you should address all 5 walls in that space.
I did 4 walls in my utility space with clips and double 5/8" and green glue. Turned the music up and was disappointed. I hadn't done the interior ceiling yet.there was sheathing on top of the joists. (Yes I know you should do the ceiling first but it wasn't possible at that stage I was in. The subsequent rooms I did ceiling first)So I proceeded to do the ceiling in that room before I did any other soundproofing in the other rooms to see what impact it would have. Well after I finished the ceiling i was amazed. The music was almost unheard unless you cranked it extremely loud then you could hear a little bit but I haven't finished sealing the doors yet. So I did clips and double 5/8" and green glue in bedroom ,bathroom, utility room.
Since I hadn't built the kitchen living room yet and I was doing a service wall interior to the exterior wall I went with a double stud approach. I only have the ceiling done as of now and the outer layers on so I can't say how much better over the clips approach it will be. But from the numbers published it should be slightly better.
The biggest gain in sound proofing comes from decoupling either thru clips or double stud walls. Doubling or tripling layers gains some but the biggest bang for the buck is in decoupling one side of the wall from the sheathing(drywall or osb) on the other side. Either strategy costs floor space and money. You have to ask yourself how much sound reduction you need, then chose a wall assembly, and then implement on all 5 walls. Some say all 6 sides but if your on concrete and it isn't a studio or home theater room its not really practical for the floor.
Well good luck I know its frustrating to get answers to sound control questions but educate yourself and pay attention to the details. They can make or break your strategy .
With any soundproofing like that your weak point will be your doors. There is no point in going nuts on wall soundproofing if you don't fix that. Weather stripped solid core is much better but still around STC 35.
Generally, I find 5x8 drywall on both sides with batts is a reasonable setup with standard doors. I do like Robert's suggestion of slitting the stud as a low cost decoupling.
The double drywall and green glue is only worth it if you have a better door and fix the flanking paths in the ceiling above and the floor bellow.
Stay away from clips or RC from walls as it makes hanging anything very difficult.
I would also do some soundproofing between the bathrooms and the adjacent bedrooms.
What would be your solution to improve on a solid core weather stripped door with a sweep?
The flanking paths in the ceiling will be addressed by running the drywall up to the plywood air barrier and sealing it off before the ceiling is done.
The floor is less certain. It's 3/4 Advantech and besides underlay and batts between joists (not sold yet) I'm not sure what else I can really do.
What I meant is solid core weather stripped door is pretty decent, but not good enough to need more elaborate wall soundproofing.
A wall with 5/8" on both sides well sealed on the perimeter with batts is around STC 45. Your weather stripped door is around 35 to 40, so it is a reasonable match for the wall assembly.
If you do want more, there are STC rated doors you can buy ($$) or you can DIY one by adding MDF layers to an existing slab. This does make the doors significantly heavier, so you have to be careful with hinges and framing. If you do build one, going with more soundproofing on the walls would be worth it.
You can limit a lot of the flanking noise with a couple of feet of batts in the floor joist bellow the wall. Not as good as solid blocking+batts, but much easier to do.
Sound is a very squishy topic, good enough is hard to define. If you have lived in older plaster and lath houses with solid doors, the 5/8 wall+batts is about that level of soundproofing.
To get to the point of not hear anything, you need get closer to STC 60, but then you would need a vestibule with two doors.
"good enough is hard to define"-that's exactly my issue in deciding where to settle.
The doors are going to be a flush paint grade style anyway so adding extra mdf would be pretty easy. This is probably my best bet
The only solution I've heard from our sound consultants beyond solid core door panels and weatherstripping is to add a vestibule and another door...not palatable or possible in many instances.
You're on the right track. Good suggestions from others above. Avoid wall mounting your TV and sound system but if you must, look into isolation clip products for it rather than lag bolting it right to the studs. Soft surfaces help immensely with mid and high frequencies but bass is a bear. Low frequency and impact noise (IIC vs. STC) is the real reason behind extra drywall and resilient channel and isolation gaps.
Seems like too much guessing. Is it effective to walk around with a sound level meter to identify exactly what needs improvement? Perhaps with high/low frequencies being played in the adjacent room so you know what type of fix to make.
If you're tight on space, adding mass is probably your best option.
If you've got space to burn, double walls are more effective, and double walls + adding mass even moreso.
Adding mass may involve going from 1/2" ultralight to 5/8" firecode core drywall, or going to 2 layers of drywall, or backing the whole thing with mass-loaded vinyl.
Soundproofing is all about the weakest link in the chain, but it's also tough to quantify your links.
Fibrous insulation is both a way to add mass, and when it's not acoustically bridged, it provides some degree of sound *dissipation*, which is a distinct quality from sound isolation. Other than the door, a tile bathroom has lots of sound isolation, but not much dissipation - it echoes. A closet filled with clothing dissipates sound nicely.
The floor is something that's much easier to address during the planning phase of the build than as a renovation. Anything that raises the finished floor level will require resetting myriad things in the house. Probably the acoustically best-in-class floors involve either CLT or concrete/gypcrete slabs, but 1 1/8" extra-thick T&G subfloor, or double layer 3/4 T&G subfloor with offset seams is probably a good deal better than typical-thickness single layer.
I agree that the doors are critical to performance. My experience is that weatherstripping is critical for door soundproofing. I have a few data points from my house that could possibly help.
- Solid core interior doors without weatherstripping, < 1/4" bottom gap- better than a hollow core, but not much.
- Double pane glass pane door in a single pane glass wall. Weatherstripped and drop seal. Clearly better than the glass wall. No sound leak, except the corners, which you can hear just a bit more noise than the rest, if you put your ear right up to the corner.
- Custom door - two layers 3/4" MDF with an internal 1" gap with 3/4" polystyrene insulation, two layers 1/4" hardwood veneer. Double door seals and rubber bottom sweep. Putting your ear to the corner still will show you that it's really hard to seal a door in the corners. Overall, aside from the corners, it's in the range of a standard 2x4 wall as far as sound attenuation.
- Solid core exterior door, weatherstripping, rubber bottom sweep. Similar to custom door above, though you can tell with an ear to the center of the door that more sound comes in through the door carcass, but given the minor sound leaks in the corners, does it matter?
I'd really focus on the door weatherstripping / sealing. It has every indication that it will be your limiting factor in both bedrooms. The difference between "just installing" and taking time to really get the door weatherstripping right may be the highest value time you spend on this project. The tiniest gaps in weather stripping make a difference.
Do you have any airflow in the bedrooms if you really seal the doors perfectly? CO2 buildup in a closed room is a real thing.
Thanks, I'm owner buildering so I'll be taking care of all the interior trim/doors, spending the time to get the door right is no problem.
Yes, HRV has a supply in the master and return in the ensuite, bedroom 2 has a supply and will have a connection to the return in the crawlspace, and I will check the performance of that before anyone lives in the room.
Don’t build the walls differently on the green/yellow corner — build them both the same way. The weaker “side” of the corner will just dominate for sound transmission and save you little money.
I also recommend avoiding the clips and channel if you don’t really need to as it makes the drywall installation much more challenging. I would probably use double 5/8” one one side and single 5/8” on the other, with sound dampening mineral wool batts (which are slightly thinner than the batts intended for thermal insulation) inside the stud bays and installed tight against the the side with the single sheet of drywall. That is a pretty easy and inexpensive wall assembly that will get you a lot of improvement in sound reduction compared to a normal hollow wall with 1/2” drywall on both sides.
I would build one of the walls like this and then try it out if you have that option. If you want more sound isolation, double up the other side of the wall — you can easily install another layer of 5/8” drywall on top of the first. You need to mud and tape for sound purposes, but no priming or painting is needed so you don’t need to waste any effort on that until you’re happy with the sound levels.
Keep electrical boxes in different stud cavities on opposite sides of the walls, don’t share a cavity. This is a bigger deal for sound than you might think. There are clay-like sound isolation pads you can install over the electrical boxes to help minimize sound leakage. Seal any holes in studs carrying horizontal wire runs too.
For your purposes a double stud wall probably isn’t necessary. I would consider doubling up on drywall on those exterior walls if you really want quiet bedrooms. Laminated glass in one pane of a double pane window will often outperform a triple pane window in terms of sound reduction too so be sure to look into that if you’re concerned with outside noise and not just noise between interior rooms.
When I renovated my home office, I replaced the drywall one one side of the walls with 5/8” (it was 1/2” before), and I added mineral wool sound insulation batts tight against the 1/2” drywall. I did nothing with the door or windows. The difference in sound transmission between the office and adjoining rooms with just this small improvement was HUGE. It’s easy to add more soundproofing than you really need which is why I suggested a test if you have that option available.
Bill