Hello.
I have a big acoustic problem. My office is in a 125-year-old building and there are apartments above. Depending on who has lived in the apartment, different sounds have always disturbed me and now I am tired of sitting with noise-canceling headphones on. So the problem is all the sounds. Above is a plastic mat, 6mm hardboard tightly nailed to the subfloor of 25mm tongue-and-groove boards where the joists are 900mm apart. So the floor is not stable. Underneath this, there are 95mm high and about 95mm wide beams. Under that, there are 25mm thick boards and in between there is a lot of sawdust. Under this top layer, there's another ceiling with a distance to yet another sub-ceiling made of 25mm boards. Beneath this, there's a 45mm support with fiberglass and underneath is a Tretex board.
None of this is really good for sound. So now to the solutions. It should also be mentioned that the floor in the apartment slopes at least 5 cm from one wall to another.
The floor needs to be stiffened and made significantly heavier. What do you think about screwing or gluing one or two layers of floor gypsum on top to stiffen the floor and make it heavier? It will be possible to screw additional gypsum board from below if needed later when the office ceiling is being installed.
Or a chipboard glued and screwed to the floor on top, possibly with a floor gypsum on top.
Alternatively, prime the floor and level it to at least 2 cm.
Right now there's water damage there, so the floor in the apartment is already exposed and the ceiling in the office will have to be taken down anyway.
Appreciate any ideas. Mats
I have a big acoustic problem. My office is in a 125-year-old building and there are apartments above. Depending on who has lived in the apartment, different sounds have always disturbed me and now I am tired of sitting with noise-canceling headphones on. So the problem is all the sounds. Above is a plastic mat, 6mm hardboard tightly nailed to the subfloor of 25mm tongue-and-groove boards where the joists are 900mm apart. So the floor is not stable. Underneath this, there are 95mm high and about 95mm wide beams. Under that, there are 25mm thick boards and in between there is a lot of sawdust. Under this top layer, there's another ceiling with a distance to yet another sub-ceiling made of 25mm boards. Beneath this, there's a 45mm support with fiberglass and underneath is a Tretex board.
None of this is really good for sound. So now to the solutions. It should also be mentioned that the floor in the apartment slopes at least 5 cm from one wall to another.
The floor needs to be stiffened and made significantly heavier. What do you think about screwing or gluing one or two layers of floor gypsum on top to stiffen the floor and make it heavier? It will be possible to screw additional gypsum board from below if needed later when the office ceiling is being installed.
Or a chipboard glued and screwed to the floor on top, possibly with a floor gypsum on top.
Alternatively, prime the floor and level it to at least 2 cm.
Right now there's water damage there, so the floor in the apartment is already exposed and the ceiling in the office will have to be taken down anyway.
Appreciate any ideas. Mats
Hello and welcome to the Byggahus forum!
Impact noise is always an issue in houses with timber floors. An ideal design could be seen from top to bottom: A floating floor that is isolated from the actual floor structure. A well-dimensioned floor structure with limited deflection and some sound absorption. A suspended ceiling, separate from the floor structure with some sound absorption.
95x95 beams (probably 4x4 inches initially) correspond to 45x120 timber and cannot handle a span longer than 175 cm with acceptable deflection. If it's your own house and you have control over the floor structure, I suggest you aim to make it as good as possible.
Impact noise is always an issue in houses with timber floors. An ideal design could be seen from top to bottom: A floating floor that is isolated from the actual floor structure. A well-dimensioned floor structure with limited deflection and some sound absorption. A suspended ceiling, separate from the floor structure with some sound absorption.
95x95 beams (probably 4x4 inches initially) correspond to 45x120 timber and cannot handle a span longer than 175 cm with acceptable deflection. If it's your own house and you have control over the floor structure, I suggest you aim to make it as good as possible.
Sounds like the upper apartment is a furnished attic, and for floor structures from that time, 150*150 mm rafters were typically used.
But as the previous speaker said, it's difficult with impact noise; one way to reduce noise is a floating floor on impact sound strips underneath, then an acoustically dampening ceiling below, also built with resilient channels on the gypsum ceiling, preferably also built with secondary channels so it isn't attached too often to the upper floor structure but becomes a unit entirely in itself.
Vibrafoam® Strip 25 mm
High-efficiency solution with impact sound strips aiming to ensure impact sound class B. Stable floor with high comfort.
Specification
But as the previous speaker said, it's difficult with impact noise; one way to reduce noise is a floating floor on impact sound strips underneath, then an acoustically dampening ceiling below, also built with resilient channels on the gypsum ceiling, preferably also built with secondary channels so it isn't attached too often to the upper floor structure but becomes a unit entirely in itself.
Vibrafoam® Strip 25 mm
High-efficiency solution with impact sound strips aiming to ensure impact sound class B. Stable floor with high comfort.
Specification
- Dimensions: Lengths 1000 x 45 x 25 mm
- Max load/m2: 400 kg
- Target: Impact sound class: B
- Impact sound improvement: Approx. 15 dB
- Material consumption: Approx. 2 m per m2
- Lifespan: Full functionality for the lifespan of the building
No, the attic is above, and it is not converted. But everything is too weak and unstable, so the problems are clear here. But in some way, it should be possible to make it significantly better at least. A 25 mm high strip is probably too much considering the build height. I also need to reinforce the floor which is too shaky as it is.T Takläggare said:
Just screwing the plasterboard doesn't make a big difference in the flex, it needs to be glued to a solid base to properly stiffen it up.
Can you install some beams from underneath, then cross-brace and thus create a stronger framework? Cc 900 gives a little creaking sound, but bringing it down to a smaller cc is a big job, which is why cross-bracing can help the 95*95 that are there.
Can you install some beams from underneath, then cross-brace and thus create a stronger framework? Cc 900 gives a little creaking sound, but bringing it down to a smaller cc is a big job, which is why cross-bracing can help the 95*95 that are there.
Yes, I will try to place a stud between each old joist. This will make the floor significantly stiffer, which is probably a prerequisite for making it quieter. It should be possible to screw the floor planks from below at an angle to avoid new noises. Maybe glue and put something soft in between as well.T Takläggare said:
What is the span of the beams? Cross bracing can reduce the deflection somewhat within reasonable limits. 95x95 corresponds to 45x120 in terms of rigidity, which is not much. An appropriate span for an acceptable deflection with this dimension is about 1.7 meters.
45x145 is not enough. For good deflection conditions, you need 45x220. This is especially important when you want impact sound insulation and cannot use glued screws on top of the floor joists. Note that the c/c distance does not have much significance for the deflection. However, it is of course logical to place new joists in between the existing ones.
I can absolutely screw-glue the top board. And I know that it's the a-measurement of a beam that indicates its deflection. But unfortunately, there isn't much height to take into account given other installations. The floor as a whole doesn't sway much; it's mostly when you load the floorboards between the rules that the floor wobbles. But I hope to measure a bit more when everything is taken apart, or pryedJ justusandersson said:
Small update in the project. Some work has now been done to restore the water damage that started the project. New floor 22 mm chipboard is now both glued and screwed into the existing 30 mm floorboards. And this floor now provides a slightly higher resonance frequency-wise, and the footstep noise here is also slightly quieter than on the old floor. The old floor (the other half of the apartment) still has all its layers of sawdust and insulation and resonance chamber as well as a ceiling as seen from the floor below, while the new ceiling has been completely cleared of everything. The joists are 135 mm wide, 170 mm high, and 3300 mm long, and since the old floor has been nailed down and the chipboard above has been both screwed and glued, the sagging has been significantly reduced.
The next step will be to see if a new joist that reduces the center-to-center spacing from 900 to 450 affects sound and sagging. Also to screw plasterboards from below directly up against the old floorboards and see if this can help eliminate vibrations in the floor from footstep noise. This before we insulate and drywall the beam structure again.
The next step will be to see if a new joist that reduces the center-to-center spacing from 900 to 450 affects sound and sagging. Also to screw plasterboards from below directly up against the old floorboards and see if this can help eliminate vibrations in the floor from footstep noise. This before we insulate and drywall the beam structure again.