Soundproof floor structure

[Lennarth Svensson]

Hello
We are going to lay a new solid oak floor in the living room and want to take the opportunity to soundproof the joists.
At the bottom of the joists, there is ceiling paneling nailed into 215 mm wooden beams. Along the walls, it is insulated with two layers of 95 mm insulation (rock wool?) while about 60 cm from the wall, there is only one layer of insulation. There are also some VP pipes and water pipes in the joists, which complicates the work. The distance between the beams is normally c/c 60 cm but can vary a few cm.
How would you go about getting as much soundproofing as possible with a reasonable amount of work and cost?

 

[justusandersson]

For good soundproofing, both for airborne noise and impact noise, you should ideally have a floating floor on top and a separately suspended ceiling in the floor below. In the cavity itself, it should look roughly as before, i.e., filled with mineral wool boards. Double thickness along the exterior walls and single over the rest of the area.

Two other things I'm wondering about: Are the beams notched at the wall edge? What is the span of the beams? The presence of cross bracing suggests that the span might be quite large. It may be appropriate to take the opportunity to install a screw-glued floor particle board before the floorboards.

 

[Lennarth Svensson]

For good sound insulation, both in terms of airborne sound and impact sound, you should ideally have a floating floor on top and a separately suspended ceiling on the floor below. In the cavity itself, it should look roughly as before, i.e., filled with stone wool boards. Double thickness along the exterior walls and single across the rest of the surface.

Two other things I wonder about: Are the beams cut off at the wall edge? What is the span of the beams? The presence of cross bracing suggests that the span might be quite large. It might be appropriate to take the opportunity to lay a screw-glued floor particle board before the floorboards.

Thanks for the response
In consultation with the seller, we have decided to only add double layers of stone wool over the entire floor and took the opportunity to seal holes in the existing insulation.

For good sound insulation, both in terms of airborne sound and impact sound, you should ideally have a floating floor on top and a separately suspended ceiling on the floor below. In the cavity itself, it should look roughly as before, i.e., filled with stone wool boards. Double thickness along the exterior walls and single across the rest of the surface.

Two other things I wonder about: Are the beams cut off at the wall edge? What is the span of the beams? The presence of cross bracing suggests that the span might be quite large. It might be appropriate to take the opportunity to lay a screw-glued floor particle board before the floorboards.

 

[Björn Melander]

The construction that justusandersson describes is an effective solution. However, you can improve airborne sound insulation by gluing gypsum on top of the ceiling panel (1-2 layers) and sealing with a soft sealant to make it completely airtight. The insulation should not be compressed. For the top side of the floor structure, do the same but with floor gypsum if the construction height allows.