Gypsum between floor joists for sound insulation between floors?

[FellanD]

Hello,
I have a couple of questions;

Renovating a bedroom on the upper floor in a part of the house that was added in the late 70s.

The joist is 8.5 x 5 meters. The beams are 220x70, cc45. Living room without interior walls on the lower floor.

It is noisy, so according to a suggestion from the forum, I am considering embedding two layers of plasterboard between the beams.
This adds about 20kg/sq.m in weight. From what I understand, joists are usually sized for 200kg/sq.m, 20kg/sq.m feels completely okay; do you agree?

I am thinking of attaching simple angle irons between the beams and placing the plasterboards on them, sealing with latex caulk around. Is this reasonable?

The span of 5 meters is on the borderline according to the wood guide tables. Ideally, I would have liked to have floor heating between the beams to save ceiling height. However, it seems that glued and screwed floor chipboard is necessary for a 5-meter span to be okay. Therefore, notching the beams 2cm at each end to allow the pipe to pass between the bays seems unnecessarily risky, don't you think? Better then to lay floor heating on top of the glued and screwed floor chipboard and sacrifice 2cm in ceiling height?

Best regards,
Fredrik

 

[Testarn]

The weight shouldn't be an issue, two centimeters lower ceiling height won't matter unless the ceiling is extremely low (so that you hit your head)

 

[spikplanka]

Sacrifice 2 cm for strength. But another way is to add an I-beam?

For soundproofing, there's this thread: Ljudisolera för sex
But for this case, perhaps a windproof layer and floor of planks or chipboard can rest on gummiduk on top of the floor joists. (on top of this underfloor heating?)
If you have at least two boards, you can add "green glue noiseproofing sealant" in between or perhaps silicone if that can't be found. If these materials compress, then add gummiduk there as well.

I imagine gypsum tends to crack? but that can perhaps be hidden with planks or a board. Just don't spill water... Otherwise, there is cement board.

 

[FellanD]

Sacrifice 2 cm for stability. Another option could be to install an I-beam?

For soundproofing, see this thread: Soundproof for sex
But in this case, maybe you can let a windbreak and a floor of planks or chipboards rest on a gummiduk on top of the joists. (on top of this, underfloor heating?)
If you have at least two boards, you can apply "green glue noiseproofing sealant" between or maybe silicone if you can't find it. If these materials sag, you put gummiduk there too.

I guess gypsum is prone to cracking? But that could maybe be hidden with planks or boards. Just don't spill water... Otherwise, there’s cement board.

You're right about the stability, of course. Just wanted to confirm that chipboard is very important under the current conditions. I've read too many threads about span width where the amazing "justusandersson" has written; so now I'm considering construction plywood instead of floor chipboard to optimize the joists.

Given that gypsum tends to crack, it must be much better to screw battens between the joists instead of using angle brackets to lay the gypsum on upon further reflection.

I've come across green glue before, not sure if it's as good when the drywall is laid on top of each other instead of mounted on the wall.
"or maybe silicone if you can't find it" - I've thought a lot about this, there should be a generic version that is almost as good. Acrylic sealant? Silicone? Flexible mounting adhesive?

 

[z_bumbi]

Attaching studs to the floor joists allows you to screw chipboards there and then the underfloor heating. You can also lay double chipboards or a stack of gypsum as long as you adjust the height of the space.

The main reason for fitting in part/all is the floor level in relation to the staircase.

 

[spikplanka]

You are right about the strength, of course. I just wanted to confirm that the particleboard is very important under the current conditions.

I'm mostly thinking about the beam getting its full strength. If a particleboard breaks, it's inconvenient, but not dangerous.