Building a room within a room – impact noise – solutions?

[chag0101]

Hello! I have an impact noise attenuation question.

If I build a room within a room on a floating floor using a Mason spring jack type system, will this make low frequency impact noise coming from an upstairs neighbor practically inaudible at night (assuming it’s done properly)? I live in a high-rise (an upper floor) cast concrete apartment building with 8-inch(20cm) slabs and I am concerned about noise coming from dragging the furniture on tiles and laminate floor at night coming from an inconsiderate neighbor (I don’t have access to the noise source to treat it there).

It’s our bedroom where we sleep, 170 sq.ft (16 sq.m), square room with a 11ft ceiling (3.30m). The perimeter walls are built from 4in (10cm) concrete blocks. I plan to build internal walls from brick (for greater mass) resting on a Mason jacked up internal floor, the internal ceiling will be half as thick as the building slab (shall do 4in (10cm) max) resting on internal brick walls (no contact with outer walls) and will use rockwool (the type that won't saddle) to fill the 2in (5cm) cavity in between the walls and also between the ceiling and the outer slab (there I can do a 4in (10cm) gap or more if need be). Don't plan to use plaster boards. As mentioned, the floor will be Mason jack up type raised from the floor slab (leaving about 1in (2.5cm) cavity, not filled). I also plan to put a pair of insulated room entrance doors and double windows as well, mounted on silicone, no foam.

So, if I build a “room within a room” on a floating floor (completely decoupled on springs), even IF some noise still passes through, will it be perceived as airborne noise rather than structural noise if completely decoupled?

I can sleep through street noise, police sirens etc, no problem, but impact noise is a killer, you can hear it in your ear through a pillow boom, boom... (I think dominant frequencies are 30-50 hz and below). Hence, I am looking for complete de-coupling solutions.

My neighbors stay up all night every night and I have no other choice (other than selling) unless I can attenuate this noise somehow, or at least convert it to airborne noise.

Worth trying?

Thanks!

[lolptyu]

How deep a wall do you want? The deeper the better. Deeper walls have a greater air volume and will isolate low frequencies better. If you plan to have several subwoofers, you should try and have the deepest walls possible. This does not mean build with 2x6 or 2x8 wall studs. Rather, space the two 2x4 walls as far apart as you can.

[DanDan]

This is a big project. One where you will need certified professional views on the load on the building etc. etc.
Not one for quick internet posts I am afraid. I have had success with neighbours by reversing the 'communication' Presumably they sleep during your day? If you were to generate some pretty high level noise, including some structure borne, doors closing strongly, etc., they may gain an appreciation of what it is like. As you know structure borne noise is really an intrusion, sounding like they are in the room with you.

[chag0101]

Thanks for the answers!

I will get professional views on the load on the building etc. Here, I am curious about acoustical aspects.

I've heard that my internal room must have its own natural resonance frequency about twice as low as the outer structure or its gonna be a waste of money, and I am not sure I can achieve that without surpassing the total mass of the outer room structure in the building which looks unrealistic, am I wrong, or is there another solution?

DanDan
I tried that doesn’t seem to work ☹

lolptyu
Inner walls will be about 4in (10cm) built of bricks with an air gap of 2in (5cm) between this wall and the existing concrete block wall which is also about 4in or a little more. (It's my bedroom, an upstairs neighbor causes impact noise, there are no subwoofers).

[gullfo]

also check with your landlord. depending on where you live, noise ordinances regarding inter-unit noise is something they are either required to adhere to and correct, or should help fund it.

[chag0101]

also check with your landlord. depending on where you live, noise ordinances regarding inter-unit noise is something they are either required to adhere to and correct, or should help fund it.

They consider using furniture even at night normal household activity, so much for that, eh... Most ppl don't understand low frequency impact sound, most start asking if their TV is too loud, do they play loud music... and when I say 'no' they think I am weird.

[DanDan]

Yes you will have to generate structure borne sound to communicate with them. Hold a brick against the ceiling and drill holes in it with a hammer drill.......
How about some ceiling attached Gym equipment. Cirque de Soleil are probably selling some stuff.... Christmas is OVER
The Mass Spring Mass (The Spring can literally that or resilient pucks of neoprene or even air etc.)
The fundamental resonance of this combination needs to be about 1/3 or lower than the lowest frequency one hopes to isolate.

[Jee]

Hi there chag0101, just wanna check if you found a solution to your problem? I'm facing the same albeit I am on the top floor and the impact noise source is from downstairs. It's a small building and perhaps due to my bedroom being on the top corner of the entire building, the vibrations terminate there as well with no where else to go. Was considering a room-within-a-room as well (after consulting with building engineer on floor load). Would love to hear if it worked for you. Thanks!

[chag0101]

Hi there chag0101, just wanna check if you found a solution to your problem? I'm facing the same albeit I am on the top floor and the impact noise source is from downstairs. It's a small building and perhaps due to my bedroom being on the top corner of the entire building, the vibrations terminate there as well with no where else to go. Was considering a room-within-a-room as well (after consulting with building engineer on floor load). Would love to hear if it worked for you. Thanks!

I have not attempted this yet. I was considering using Sylomer as a floating floor foundation. For the time being I am using foam ear plugs together with Peltor earmuffs and this helps a bit. But for a lasting solution, you will likely need a room-within-room design floated on some elastomer such as Sylomer. Anything less than this probably won't work. But I am not sure even if this will work for a low frequency impact noise insulation. At certain frequencies, below that of Mass-Air-Mass resonance (Air being your elastomer) the vibration may be worse (not dampened but made worse...)

Interesting to hear that this interfering vibration can be derived from downstairs.

I am impacted by the vibration from next doors and upper floors, even two floors up. Hard to insulate. Room within room MAY be the only realistic solution though as the floor is the main conduit.