ᐅ Interior walls: gypsum board or OSB panel?

Hello everyone,

We still need to make a decision about our interior walls at some point.

Our builder explained the (Q-)options for selecting the interior walls as follows:

• 12.5 mm gypsum fiberboard + 12.5 mm gypsum plasterboard
or
• 13.0 mm wood-based panel (e.g., OSB) + 12.5 mm gypsum plasterboard

Both options should be similar in load-bearing capacity, do you think so? I have a gut feeling that the option with the OSB panel might be somewhat stronger. On the other hand, I’m not really sure what additional load capacity we would need. I think a hanging kitchen cabinet sets the benchmark here, and both options should easily support that (even the new desired TV weighs only 35 kg).

Since we are planning a mechanical ventilation system with heat recovery, and it’s sometimes said that the air can be a bit drier with this system, one might argue that the double gypsum boarding could store and release twice as much moisture. But that is just a speculative theory of mine...

What would you do?

I appreciate your opinions because we will have to decide eventually 🙂.

Nixwill schrieb:

Since we are planning a mechanical ventilation system with heat recovery and sometimes hear that the air can be a bit drier with this, one might say that double drywall might also store and release twice as much moisture. But that is a theory I just made up...

Yes, that’s far-fetched. The indoor air humidity will drop to 30-40% very quickly in winter if you don’t include an enthalpy heat exchanger. It doesn’t matter what kind of walls you have. Unless you spray them daily with a garden hose.

Great idea! I also have a pump spray bottle lying around here, so it should work fine for starters :p.

EDIT:
But I’ll take a closer look at the enthalpy exchanger... (Does it make sense if you already have problems with dry eyes?)

Nixwill schrieb:

Does it make sense if you already have problems with dry eyes?

Not only then, always! If you already have issues. Then the question doesn't even arise. Without an enthalpy exchanger, you won't be satisfied.

Mycraft schrieb:

Yes, that’s quite far-fetched. The air humidity drops to 30-40% in no time during winter if you don’t plan for an enthalpy exchanger. It doesn’t matter what kind of walls you have. Unless you spray them daily with a garden hose.

It’s not that simple. Here is our record from January 2021 – without an enthalpy exchanger:

Tiled stove, large room volume, clay plaster walls, quite a lot of untreated wood (acoustic ceiling, gallery, staircase)

Just like in your case, it usually looks like that for me too! On average, between 50 and 55%.

If I’m not mistaken, you don’t have a mechanical ventilation system with heat recovery, right? We currently don’t have one either, which actually is a decent compromise. However, such systems can be quite problematic... As I mentioned earlier, I need to look into enthalpy exchangers.

I don’t want to focus the discussion too much on humidity now, but rather on what you think about the different wall constructions.