Counter battens in the interior area for roof insulation

Hello forum,

and first of all, Merry Christmas to everyone.

I have a question regarding the counter battens for my roof insulation work.

I have installed 200 mm insulation between the rafters in my roof structure and sealed it with a vapor barrier foil.

Now I want to install the counter battens (24 mm roof battens, the spaces in between will also be insulated) in order to attach the gypsum boards to them.

What spacing of the battens is best to choose?

A 600 mm spacing seems too wide to me, could the gypsum boards sag or possibly warp over time?

I have started the first batten at the knee wall and then set 600 mm spacings upwards. At the top end, I have fixed another batten.

Or should I place a batten along the rafter course?

Hello,

also Merry Christmas. So I would recommend a slat spacing of 31.25 cm. Because the panel is 1.25 m wide, divided by two is 62.5 and that divided by two is 31.25. Otherwise, the panels will sag over time. Otherwise everything looks okay. No batten needed on the rafters. Inside I might recommend wood fiberboard instead of gypsum board. These serve very well as an active heat storage and thus create coziness in the room. Otherwise just glue the vapor barrier. That is the most important.

Best regards

I would also rather use gypsum plasterboards, as they are exceptionally capable of buffering humidity peaks, are easy to work with, and (including the joints) form a continuously smooth and even surface.

Regarding the substructure:
If it is to be a single-layer wooden substructure, I would follow the installation guidelines of the respective system manufacturer.

The battens to be used should have minimum dimensions of 50 x 30 mm.

Their spacing depends, among other things, on the weight of the cladding. If there are no fire protection requirements, a single-layer cladding with 12.5 mm thick gypsum plasterboards arranged parallel to the rafter direction (i.e., perpendicular to the substructure) might be considered!?
In this case, the batten spacing should be chosen up to a maximum of 50 cm (see manufacturer!).

Before installation, you should in any case ensure by means of a differential pressure-supported leakage test that the airtight envelope functions without gaps! For this purpose, you can commission a complete blower door test or optionally perform this check for leaks yourself.
You can find measurement service providers or equipment rental companies, for example, at luftdicht.de.

With Christmas greetings
KPS

Hello,

I also see the advantages with GK here. The deflection can vary depending on the material and manufacturer, so I would follow the respective recommendation.

But what do you want to achieve with the thermal insulation in front of the vapor barrier?

Best regards

The originally described insulation arrangement in the cavity between [GK-Bekleidung] and [Dampfbremse]/[Luftdichtheitsebene] undoubtedly reduces thermal bridges in the rafter area and additionally improves the room acoustic properties in the living area. Therefore, it should definitely be implemented.

@KPS

why is that, if the condensation water of the vapor barrier is absorbed by the insulation, the "thermal bridge" would always be higher than standing air,
moreover the thermal insulation is almost zero.

Room hygiene not even mentioned. (especially with GK)