Soundproofing interior wall wood fiber / interior doors

Hello,

we are currently insulating our interior walls, 12cm wooden studs, with 80mm wood fiber mats SteicoFlex WLG40. That was included in our expansion package. Now we are considering whether to add another 40mm wood fiber boards in the "critical" rooms such as the transition between the children's room/bedroom/bathroom for soundproofing. Does that make sense or is there hardly any added value? Is it possible to somehow quantify this in a unit like dB? I couldn’t find anything in the technical sheets from Steico.

On Friday we had the sampling appointment and it was about the interior doors. The consultant recommended solid core instead of hollow core for the mentioned rooms, also due to soundproofing. However, we have installed a controlled residential ventilation system, so the door leaves would have to be shortened to ensure air exchange. Here the question arises again whether solid core is even sensible then?

The solid core is definitely sensible. You don't have to shorten the doors at the bottom because of the [Kontrollierte-Wohnraumlüftung]. First, consider which doors they are and whether they are not usually left open anyway.

And secondly, you can have the door top milled open at floor level, that's how we did it. It's much better for sound insulation and invisibly allows good air exchange!

The thing with the shortened doors I’m hearing for the first time as well
Looks shitty too...

The shortened doors are nothing new, but there are other ways to ensure air exchange with controlled residential ventilation while still maintaining good sound insulation in the house.

As an example, frames or drop seals with an air gap come to mind.

For an air volume of 30 m³/h, a gap of 0.7 cm is required for an 80 cm wide door. In the case of supply air ventilation, the overflow opening should be located in the upper area of the room. Overflow openings over a milled frame provide an invisible solution here.

There are also special solutions for overflows in doors and masonry.

Hm ok, I apparently need to inform myself again about the overflow options. The milling sounds relatively simple and cost-effective. Does the advantage of the solid wood then bring me a significant added value? We were quoted an additional price of about 70 EUR per door

Full-core or tubular core is now secondary. Sound is measured in dB and doors have sound insulation classes. Just ask your contact person what is offered in this regard. However, before that, you should be clear about what you need.