Insulation inside against exterior wall.

[Awes78]

I am renovating a small room where I am going to replace the insulation (sawdust) in the wall and floor. Replace the boards with OSB and drywall.
The wall facing the outer wall (southern exposure) looks like this (how do I attach an image?) after I have removed the 12mm Karlit panel. Boards and sawdust almost all the way up. About 15 cm is missing. And behind paper.
My question now is, is this an air gap or has it just settled over time?

 

[Awes78]

 

[Awes78]

After what I've searched and read, it's probably just collapsed over time.

 

[SBH]

Yes, shavings and loose wool settle over time. Even insulation in sheets.

 

[anders07]

I'm absolutely no expert in older building techniques, but check with someone who knows to ensure it doesn't become too sealed with OSB+Gips. Many older walls are designed to "breathe" from both sides...

 

[Awes78]

I seem to have seen or read that the OSB board is made a few cm smaller around. But the drywall and the rest all the way to the wallpaper should be smooth and tight, right? Otherwise it will be drafty?

 

[Awes78]

I continue on my old thread.
Have not gotten further than the pictures for various reasons.
My previous question remains.
Then I apologize for my silly questions.
But I'm going to tear up the floor now. And I wonder if there are any risks with that?
Could the floorboards be part of the construction so that they hold the beams in place?
That is, if I tear them up today and leave it open for a while. Could the beams go astray and change shape so that it becomes damaging to the house?

 

[Awes78]

The floorboards are approximately 30mm thick. And there is a 65 cc gap between the joists.

 

[Oldboy]

There should be no danger with the floor joists just because you're ripping up a solid old floor. However, I think you should remove it completely so that it can be reused. That type of genuine solid flooring costs a fortune today.

I also think it's unwise to replace a solid plank wall with flimsy and synthetic OSB & gypsum.

You can fill up the insulation in the wall cavities (also the floor) by spraying in loose-fill (cellulose-based).
Regardless of how you do it, the wall and floor should be 100% windproof. This is not the same as moisture-proof. Windproofing is achieved with caulking in older houses (+ moldings). (Also, of course, wind barrier paper and panel materials like masonite & tretex.)

 

[Awes78]

Mm I understand your thoughts. But the planks on the wall are not as sturdy as the floor. They are reused and joined everywhere.

Is there worse stability with OSB, etc., compared to wooden planks?
Or why is it considered bad?
As I said, I don't know. So feel free to share opinions and experiences.

 

[guggen]

The floorboards are about 30mm thick. And there is a 65cm center-to-center distance between the beams.

You should do a slightly larger analysis.
Sealing walls, floors, ceiling beams, etc. and slapping on cheap sealing materials can mean that you quickly encounter lots of problems and damage the house. I would be careful about tearing down walls and floors if they are not damaged, but maybe they are? I would insulate carefully with open materials. You can usually insulate the floor from underneath.

 

[Oldboy]

Mm I understand your thoughts. But the planks on the wall are not as solid as the floor. They are reused and jointed everywhere.

Will there be worse stability with OSB etc compared to wood planks? Or why is it a bad idea? As I said, I don't know. So please share your opinions and experiences.

I like solid massive natural materials. They feel better for the environment & health, and give me a better sensation. Additionally, we know they work long and well in old houses built for these materials. New materials are made for new houses. The conditions are different between new and old houses. It's a bit like a Ferrari not performing as expected out in the forest... It is optimized for other conditions.

Now, it is probably fine to have OSB + drywall instead of a plank wall with Masonite and/or Tretex. I don't deal with particleboard/MDF because they contain synthetic glue. Additionally, they lose all their bearing strength if they get wet, and due to the glue, they are significantly more moisture resistant than Masonite and Tretex, which consist only of wood fibers without additives.

The stability of the wall does not get worse with OSB & drywall.

As for floors, I believe there is nothing better, more beautiful, more durable, or more comfortable to walk on than solid massive plank floors. (unvarnished)

Economy: Not touching/redoing something that has nothing wrong with it is obviously the cheapest. Or making the smallest possible intervention, i.e., only what is absolutely necessary. Common solid lumber that you buy at the lumberyard is generally always the cheapest compared to modern materials. At least if you do the work yourself. And if you are not after a modern look. If you want completely smooth, straight, and expressionless lifeless walls, then the modern materials and methods are better. However, if you prefer walls with character, you go for tried-and-true materials & methods.

In the end, it is up to you what you want/like/feel comfortable with. But, always with old houses, you need to know what you are doing to avoid making a mistake from lack of knowledge. (Yes, that really applies to everything you do, but sticking to the topic here.)

 

[Awes78]

Mm now it didn't become easy.
So the sawdust as insulation is not something you actually want to remove?
I also think it will be difficult to lay a floating floor on top of the uneven floorboards that are there now.

 

[Awes78]

Let's say I keep the wooden floor with the chipboard underneath.
Improve the walls with new insulation where it's missing. And nail up new boards.
What should I then apply on top to be able to wallpaper and lay a new floor over the floorboards?

 

[guggen]

Is it too uneven to place renovation plasterboard directly on the firewalls?