We live in a townhouse from the 1980s where we share one side/wall with another property. We have problems with the acoustics in the floor on the ground floor where sounds from the neighboring property are clearly heard (if they drop something on the floor, run/jump/stomp, drag a chair without pads, etc.). No other sounds are heard through the wall.
Of course, we understand that it will never be completely quiet in relation to the neighbor in a townhouse, and we have no problems with certain other structural noises (vibrations from stairs, etc.). I have read through quite a few threads previously in the forum that deal with similar problems but haven't become much wiser.
I am looking for measures that could be taken to reduce noise from the floor and would need help with considering and understanding how the sounds are transmitted. I attach drawings of the slab and subfloor, the wall between the properties, and the intermediate floor structure.
An idea I have personally been considering is to replace plastic wrap, sand, and celloplast with a nivell floor with acoustic screws. Since it's already a risk construction with the floor today, you could kill two birds with one stone.
Unfortunately, I am not sure if the sound travels through the neighboring property's floor, then through 2.5 cm of celloplast which the slab is divided with according to the drawings, and then back up through our floor. But maybe someone else can answer if that's reasonable
If it is executed as drawn, the construction is okay in terms of sound. The weakest point in the structure is against the floor where there is only 1 layer of gypsum. It probably depends on where the heating pipes to the radiator go. Or is it an electrical cable?
There are 2 floors as well. There should reasonably be a difference between the lower and upper floor?
Additional gypsum can help, but flank transmission is difficult to address on the efficiency side and easier to address where things are set in motion.
If it is constructed as drawn, the construction is okay from a sound perspective. The weakest point in the setup is towards the floor where there is only 1 layer of gypsum. It probably depends on where the heating pipes go to the radiator. Or is it an electric cable?
It's 2 stories as well. There should reasonably be a difference between the lower and upper floors?
Additional gypsum can help, but flank transmission is difficult to address on the effective side and easier to deal with where things are set in motion.
Yes, that was my first thought too. It looks like it is well thought out. Then it's hard to see if there is actually foam insulation in the slab since it's completely cast on the sides so from the outside you can't see it.
The second floor doesn't have the same problem. Sure, you can hear structure-borne sound, but it's more like dull thuds or vibrations at most. The problem on the ground floor is very different. If someone drops something hard on the floor in the neighboring property, it sounds exactly like it was inside with us.
One consideration I had was to put up 70-regulations with a 1cm gap from the current wall and attach double-layer gypsum with acoustic focus, etc. But since the sound doesn't seem airborne, I'm not sure it would help.
Regarding the floor where there is 1 layer of gypsum, it's true that the radiator pipes go there. You could quite easily move them out and install them on the outside and gypsum over there if desired.
A small update in my ongoing investigations to find out how floor sounds propagate and what might be done
I removed the floorboard against the wall bordering the adjacent property and found something that looked strange to me. Behind the radiator pipe at one spot, I could see a gap between the plasterboards of about 1.5 cm where I only saw black plastic. I took out the drawings again and found the following (attached image).
The partition wall seems to be constructed in blocks, or sections, where it is jointed according to the drawing (unclear how many, I can only find one joint). Where one section ends, there is a stud, then there is a 1.5 cm gap to the next stud and the next section. In between, there is insulation and plastic.
These blocks do not appear to be staggered in any way if you look at the sketch.
Frankly, I don't understand how it can soundproof at all against airborne noise, but it seems to work well
The question is if this could be a culprit regarding the floor sounds. If so, it might suffice to build a freestanding wall with 45 or 70 studs according to the rules of conventional soundproofing.
A little update in my continued investigations to figure out how floor noises propagate and what can be done
I removed the floor molding against the wall adjacent to the neighboring property and found something that looked strange to my eyes. Behind the radiator pipe, I could see a gap between the gypsum boards about 1.5 cm where I only saw black plastic. I pulled out the plans again and found the following (attached image).
The dividing wall seems to be built in blocks, or sections, where it is joined according to the plan (unclear how many, I can only find one joint). Where a section ends, there is a stud, then there is a 1.5cm gap to the next stud and the next section. In between, it is filled with insulation and plastic.
These blocks do not appear to be offset in any way when looking at the sketch.
Frankly, I don't understand how it can soundproof against airborne sounds at all, but it seems to work well
The question is whether this could be a culprit regarding the floor noises. If so, it might suffice to build a freestanding wall with 45 or 70 studs according to all the rules for standard soundproofing.
What do you think?
[image]
these are prefab blocks, so it makes sense that it is continuous. Since there's only one layer of gypsum at the floor, the seam is visible because the second layer is installed on site. It diminishes a bit. But we're talking about maybe 15x45 mm, so it's a minimal area of the total.
behind the baseboard, you have the radiator pipe, which you ideally don't want to enclose. It has held since the Dackefejden, so it probably won't start leaking spontaneously.
Start by trying to cram in some gypsum over the seam. About 10 cm long, and screw it in. Does it get better? Then we've located the problem there. If it doesn't improve, it's the overall construction. Probably both if I were to guess.
building a partition wall outside works with 45 or 70 studs, some mineral wool, and double gypsum boards. It takes up some floor space, but that might be acceptable if it provides a better sound environment.
Or you put 1 board on the existing construction. Make sure to fit around the radiator pipe at the bottom, so you don't screw there.
both options will make an improvement. A partition wall better than a single board.
