Can I just replace the sawdust with insulation?

[Davion]

But it has been 100 years since the house was built, and in 2022 we no longer want to freeze indoors; most people want 20 degrees or at least 18. With rising energy prices, it is very expensive today to heat a house from 1920. Maybe it takes 30 to 40 thousand kWh? Therefore, TS wants to insulate. Then comes the risk of moisture.

Anticimex and the construction company don't care about TS's electricity bill but don't want to take on any risk. Therefore, it's easiest to give the advice "leave it as it is, it's worked for 100 years," or "just insulate a little, and preferably with the same."

For it to make any bigger sense (economically), a significant improvement is needed, i.e., much better insulation, i.e., increased risk.

If you ask the companies that spray loose fill insulation in the attic, you'll surely get another answer, where the risk is downplayed.

Good points in general, though not quite applicable in my context.

Anticimex did not benefit in this context from one thing or another as they were already doing their job towards the broker/seller where they wrote the same thing that was later certified by them again when I purchased the same service but as the buyer of the house.
The construction company I have at home now has done a myriad of jobs in old houses. I've gone through some of their work. They are comfortable with and have guarantees around both opening to the ridge and replacing solutions in the attic.
A couple of those jobs are included in their reference catalog. In my case, they offered to do the work of changing the insulation solution so risk limitation is not "the case," but in the context, they included their interpretation of the situation.
One can speculate about their potential agenda, but from my understanding and research, their interpretation is primarily not influenced by anything akin to cowardice or malice, and they are credible for several reasons. Personally, I trust two separate certified inspection technicians at Anticimex + the firm currently with me more than the other forum member.

If I express myself like this:
I understand the drawbacks of wood chips. I am aware that there are businesses and entities that conduct their operations exactly as you describe. However, I am personally not a fan of the tinfoil hat cynicism that characterizes the other forum member and do not think that TS has received as poor advice as they want to portray.

 

[fribygg]

but what is it you don't understand, it's not just about insulation value, but sawdust has several bad properties, which is the reason it is no longer used even in building conservation.
And if you're going to use it, special variants of sawdust have been developed to make it usable,

At hallahus.se you can learn more about insulating old houses

I would love to see a source for your claim that sawdust is not even used in building conservation.

 

[GoC]

but what don't you understand it is not just about insulation value but sawdust has several bad properties, that's the reason it is no longer used even in building conservation.
And if you're going to use it anyway, special variants of sawdust have been developed to enable its use,

Feel free to elaborate on your statement regarding what the bad properties of sawdust entail.

 

[Aunty]

You are welcome to elaborate on your statement about the poor qualities of sawdust.

Besides having a poor lambda value, it compresses significantly over time.

The biggest risk with wood shavings is that it is flammable and therefore should not be used. If you still intend to use it, it should be fireproofed, alternatively, there is a company that works with treating the shavings with cement.

It can easily be attacked by pests.

 

[GoC]

apart from having a poor lambda value, it compresses over time quite a lot.

the biggest risk with kutterspån is that it is flammable and therefore must not be used.
if you are still going to use it, it should be fireproofed or alternatively, there are companies that work with treating the sawdust with cement.

it can easily be attacked by pests.

Doesn't matter in an old house. My house has a timber frame on the ground floor and double plank walls with tretex on the upper floor and sawdust in the attic with some loose wool on top.
You forget sawdust's hygroscopic advantages as it absorbs moisture that seeps up through the roof and is absorbed/distributed in the sawdust.
No, you are wrong, you are talking about modern construction techniques. Then, of course, sawdust is not a particularly good solution.

 

[nybyggarn3]

besides having a bad lambda value, it compresses significantly over time.

the biggest risk with kutterspån is that it is flammable and therefore must not be used.
if you are still going to use it, it should be fireproofed or there is a company that works with treating the shavings with cement.

it can easily be attacked by pests.

That thing about fire is not entirely uninteresting. I have insulated my entire house (new build) with recycled cellulose. Burned some of the scraps, burns well regardless of what the manufacturers claim for fire protection.

 

[GoC]

That thing about fire is not entirely uninteresting. I have insulated my entire house (new build) with recycled cellulose. Burned up some of the scraps, burns nicely regardless of what the manufacturers claim for fire protection.

The question is whether it burns so well in an enclosed space like a wall or an even layer up in the attic.

 

[Aunty]

It doesn’t matter in an old house. My house has a timber frame on the ground floor and a double plank wall with tretex on the upper floor and sawdust in the attic with some loose wool on top. You’re forgetting the hygroscopic advantages of sawdust as it binds the moisture that penetrates through the roof and is bound/balanced in the sawdust. No, you are wrong, you are talking about modern building techniques. Then, of course, sawdust is not a particularly good solution.

But I've said several times that there are materials that have the good properties of sawdust, like cellulose.

timber walls are very good from a fire safety perspective, so now you're talking nonsense.

 

[Aunty]

The question is whether it burns as well in a closed space like a wall or an even layer up in the attic.

of course it burns it's not non-combustible, but a huge difference compared to kutterspån.

 

[GoC]

But have said several times that there are materials that have the good properties of sawdust, such as cellulose.

Log walls are very good from a fire protection point of view, so now you're rambling.

Cellulose is an excellent insulation material, as well as log walls which also have good fire protection.
But you don't need to remove the sawdust when you can just as well add a layer of, for example, warmfiber.

 

[nybyggarn3]

The question is whether it burns as well in a closed space like a wall or an even layer up in the attic.

To some extent it certainly burns more compared to mineral wool. On the other hand, we have no air gap in the eaves where flames can hit.

 

[ClasseClas]

apart from having a poor lambda value, it compresses a lot over time.

the biggest risk with kutterspån is that it is flammable and therefore must not be used.
if you still want to use it, it should be fire-impregnated, alternatively, there is a company that treats the spån with cement.

it can easily be attacked by pests.

What kind of pests attack spån?

My practical experience with kutterspån is that mice don't build nests there. However, they build nests in stone wool with much joy. What is your practical experience with said phenomenon?

 

[Stefan1972]

I think you're talking about different things all the time. What does it matter what is used in new houses anyway? And no, the use of by-products as insulation wasn't stopped because it was bad, but because new products came onto the market that were better, made construction faster, and made everything simpler and probably cheaper. Just like with many other things. That doesn't mean that old products should be despised. This is something that modern particle board carpenters like to say and advocate though. In the attic of an old house, you can very well add more sawdust. It improves from the starting point. No one is saying that you want to achieve the same values as modern insulation. Then there's the idea that it can be attacked by pests and mold, which I don't understand at all... It's rarely a major problem in old houses as long as they haven't been renovated by any particle board carpenters who have advocated other solutions...

 

[boohoo]

A reflection as I have similar thoughts about removing old wood shavings and adding insulation to the attic without any real vapor barrier.

How would it be to apply a layer of closed-cell polyurethane foam to achieve a diffusion-tight layer? Then insulate with whatever you want on top of that?

 

[Stefan1972]

A reflection as I have similar thoughts to remove old cuttings and add insulation to the attic without any real vapor barrier.

How about applying a layer of closed-cell polyurethane foam to achieve a diffusion-tight layer? Then insulate with whatever you want on top of that?

and what do you achieve with that then? If you have an old house, you probably get the best result by complementing what you have with more cuttings or by injecting some modern cellulose or similar. Then you can just add it like they did in the past, and you don't need any air gaps or other hassle, and everything breathes just fine anyway.