ᐅ Which material is best for interior insulation in timber frame construction?

Hello,

we are currently looking for an interior wall insulation solution for our timber frame house.

It is important to us that the insulation is easy to install ourselves and that the material handles moisture well—that it does not mold quickly if it gets damp, but can also release the moisture again. The rest of the wall consists of OSB and double-layered gypsum boards. The exterior wall is insulated with blown-in cellulose.

Our general contractor recommends mineral wool for its cost-effectiveness.

We know there are also options like hemp and sheep wool, but we are not sure how these materials perform in terms of workability and moisture behavior and would appreciate your input. Thank you.

So, do you want to insulate the installation level with this? Or why do you need interior insulation in a new timber frame construction?

Yes, it is about the interior insulation installation layer. On top of that, drywall panels will be installed, followed by plaster/paint.

Wood fiber insulation, for example from Gutex ThermoFlex, is relatively affordable and easy to install. Moisture should not be an issue indoors at all...

We insulate using ThermoHemp (a hemp-jute blend) in the installation layer, the roof, and the interior walls, and we use loose-fill hemp for the exterior walls.

Both have their pros and cons.
Hemp is generally resistant to mold and can absorb and release moisture well.

Loose-fill hemp:
Pros:
* does not need to be cut
* can be “stuffed” into any space
* completely untreated natural product
Cons:
* creates a lot of dust
* needs to be “fluffed” before installation
* getting the right “amount” is not that easy

ThermoHemp:
Pros:
* produces very little dust
* can be cut reasonably well with the right cutter
* when buying larger quantities, the mats are cut to fit your joist or cavity spacing
Cons:
* not as firm as, for example, wood fiber, so it doesn’t hold as well in cavities
* contains recycled PET in addition to hemp and jute (I don’t like that, but others don’t mind)
* must be cut

With ubakus, you can check which insulation appeals more to you or see what effects it has on your house.

We are satisfied with the hemp, even though fluffing the mats and the dust from loose-fill hemp is a bit annoying.

We have written a lot about this on our blog.

If I understand correctly, this is about an exterior wall. When the construction is done properly, there are no issues with mold; if it is done incorrectly, every type of insulation will have problems. Using only a gypsum board is not sufficient.