ᐅ Counter-battening for Interior Roof Insulation

Hello,

so you mean I should skip the insulation between the vapor barrier and the drywall panels?

And, if I understand correctly, the battens should be installed in the direction of the rafters?

I would rather not remove all the battens again now.

Attaching the battens additionally to the rafters would be another option.

The pictures are now finished.

Here is the arrangement of the battens before:

and here afterwards; I also renewed the inside of the dormers:

So you mean I should skip the insulation between the vapor barrier and the drywall panels?

I wouldn’t recommend that, as the moisture content is elevated in the first few years with solid construction. Due to the unfavorable sd-values, I cannot completely rule out mold growth.
The sound insulation also doesn’t improve much since the insulation between the rafters is probably sagging already. You can possibly improve this more by working on the surface finish.

And, if I understand correctly, the battens should run in the rafter direction???

The battens are called counter battens because they secure the membrane.
As it’s currently installed, the membrane is only held at certain points; the correct method is to support it along its length so that it doesn’t sag as much and isn’t so heavily stressed by wind.

Best regards

parcus schrieb:


I would not recommend it, as the moisture content is higher in the first years with solid construction.

That's true; in this regard, a timber frame house is much more favorable...

parcus schrieb:
Due to the unfavorable sd-values, I wouldn't completely rule out mold growth.

I also would not completely rule out mold growth in the house, although not necessarily due to the installation of insulation beneath the rafters...

parcus schrieb:
The sound insulation doesn't add much, ..... You might achieve more on the surface here.

Cavity damping and sound-absorbing materials installed on the room side of the cladding layer are certainly two different things...

While the insulation beneath the rafters counteracts resonance-related amplification within the cavity, the absorber layer on the room side reduces the (amplified) reverberation in the living space...

I definitely find it more effective to prevent the formation of increased sound levels than to combat already elevated noise...

parcus schrieb:
... since the insulation between the rafters is probably already sagging ...

With a clear spacing of the substructure of about 25 cm (10 inches), that seems unlikely...

parcus schrieb:
The battens are called counter-battens because they counter the membrane.

Well, I would spontaneously like to ask for permission to use this phrase in other forums (of course, with the source cited)!

(In interior construction, however, one usually speaks of base battens and support battens, and sometimes of pressing battens when it comes to mechanical tension securing of bonded joints.)

parcus schrieb:
As it is counter-battened now, the membrane is only held at points, but it should be held along the entire length...

This should also be corrected!

parcus schrieb:
so it doesn’t bend or sag so much

This statement is hardly justifiable either.


Best regards from Erfurt
KPS

Happy New Year to everyone.

There is still an underlay membrane between the roof tiles and the rafter beams.

Regarding battens:

Just based on intuition, I would say that my battens with a 300mm (12 inches) spacing relieve more tension on the membrane than battens directly on the rafters with a 600mm (24 inches) spacing. Especially since, as mentioned in the previous post, the insulation wool would sag along the entire length, creating increased tension on the adhesive seals.

I will continue installing the battens as I have already completed in two rooms.

For filling the gap (between drywall panels and vapor retarder), there are now two opinions with respective advantages and disadvantages.

Could it happen that condensation forms on the membrane if no insulation is installed? (Caused by the membrane's cooler surface temperature compared to the indoor air temperature.)

Or does the membrane used actually prevent this and would instead be impaired in its function when installed together with insulation?

Venice schrieb:


Between the roof tiles and the rafter beam, there is still an underlay membrane.

I already suspected that, but the Sd-value of the underlay or secondary roofing membrane would also be of interest here...

Just by intuition, I would say that "my" battens with a 300mm (12 inches) spacing relieve tension on the membrane more than battens fixed directly on the rafter with a 600mm (24 inches) spacing...

I agree with that!

Could condensation form on the membrane...?

Definitely, whether with or without insulation beneath the rafters...

To prevent mold growth, all contributing factors and conditions must always be taken into account!

KPS