ᐅ Triple-layer drywall installation on individual interior walls

Hello,

with most timber frame house suppliers, the wall construction is usually designed so that on the living space side (after the insulation) a 15mm OSB board (about 0.6 inches) is installed, followed by a 12.5mm plasterboard (about 0.5 inches).

For soundproofing reasons and to securely fix cabinets or similar items, we are considering installing an additional plasterboard layer on certain walls as a DIY project.

I have read in various forum posts that this is possible and can be quite effective. Do you also think this makes sense for our purpose?

Is the following procedure correct?
Assuming the first plasterboard layer has been properly jointed:
1st step: screw on the second plasterboard layer with drywall screws, staggered
2nd step: apply primer into the joint (where the plasterboards meet)
3rd step: fill the joint and screw heads with joint compound
4th step: sand the wall
5th step: prime the entire plasterboard surface
6th step: paint

Should I inject elastic acrylic sealant into the joint to prevent cracks in the plaster later on?

Another option suggested by the house builder would be to use 22mm OSB boards (about 0.9 inches) instead of 15mm, and keep just one layer of plasterboard.
What do you think about this proposal?

Can anyone tell me how much a 15mm OSB board, a 22mm OSB board, and a 12.5mm plasterboard reduce sound transmission?

Thank you for your answers
Robert

Cabinets should hold securely with OSB panels without any issues. For soundproofing, we will use Knauf Diamant boards instead of standard drywall. When it comes to soundproofing, you also need to consider the doors, so they don’t become the weak point and allow sound to pass through.

Adding an additional layer of drywall will definitely improve sound insulation. In this case, I would recommend using Knauf Sonicboard. It has more mass than standard drywall, which provides better soundproofing.

RobertHell schrieb:

In most timber frame house providers, the wall construction is usually designed with a 15mm OSB board followed by a 12.5mm drywall panel on the interior side (towards the living space) after the insulation.
For soundproofing reasons and to securely mount cabinets or similar items, we considered adding an additional drywall panel ourselves to certain walls.
In other forum posts, I have occasionally read that this is possible and even quite reasonable.

There are enough forums that you will find someone who likes every idea. Regarding soundproofing, it would be interesting to know which kind of noise is being referred to. As for heavy cabinets, I would rather suggest having the second-to-top layer reinforced by the manufacturer.

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Thanks for your previous responses.

Can anyone tell me if I can securely attach a tall cabinet plus contents weighing about 60 kg (132 lbs) to a wall made of 15 mm (0.6 inches) OSB and two layers of 12.5 mm (0.5 inches) drywall?
If this is possible, the 22 mm (0.9 inches) OSB would be unnecessary.

Our concern is structure-borne sound.

I would also appreciate feedback on whether the following procedure is correct:
Assuming the first drywall board is properly finished with joint compound:

1. Step: Attach the second drywall board offset using drywall screws
2. Step: Apply primer to the gap where the drywall boards meet
3. Step: Fill the joint and screw heads with joint compound
4. Step: Sand the wall
5. Step: Prime the entire drywall surface
6. Step: Paint

Should I inject flexible acrylic sealant into the joint to prevent later cracks in the plaster?

Good luck

I can't really comment on your planned triple-layer cladding right now, but I just remembered that insulation in the walls also plays a role in overall soundproofing.
For example, whether there is still air inside the wall (avoid fully stuffing insulation in interior walls) and also the material used. Wood fiber or mineral wool might be better for this than lighter glass wool.

To prevent cracks, it’s best to embed mesh tape when applying filler. 😉