Hey, I need some help with a question. My partner's brother is going to add insulation to his upper floor, which currently has 10 cm of insulation. It's glass wool from the 70s. I told him to tear everything down since he's going to add ventilation which doesn't exist right now. The dilemma is, I think he should add at least 20 cm more so he has a total of 30, but he thinks a max of 25 cm since he feels it takes up too much space, which is about 70 sqm now. What do you guys think in the forum? Second question: I say he should replace all the insulation with new ones, but he thinks he should reuse it to save a few thousand. If he reuses it, the old insulation won't fit since he's going to make the sections smaller. What do you think?
Is it a question of interior additional insulation?
Is it a 1&1/2 story house or a purely two-story house?
Should the sloped roof also be additionally insulated (if it's a 1&1/2 story), or is it just the gable wall?
Where in our elongated country with very different climates is the house located?
Is it a 1&1/2 story house or a purely two-story house?
Should the sloped roof also be additionally insulated (if it's a 1&1/2 story), or is it just the gable wall?
Where in our elongated country with very different climates is the house located?
Yes, interior additional insulation, 1 1/2-story with sloping walls also, gable walls and attic space, it is located in Skåne outside Hässleholm kind ofOldboy said:
It
If it's internal, I would say a maximum of 5 cm additional insulation.
Reuse?
Why should the old insulation be removed?
If, for some inexplicable reason, the old insulation is removed, it's better to dispose of it and buy new. It's not necessary, but it's less unpleasant to work with new insulation. In addition, there is the opportunity to buy a more high-quality insulation, i.e., with a better lambda value. It might even correspond to a couple of extra cm of standard insulation.
15 cm well wind-protected insulation is sufficient in Skåne. I would even argue that it's more important to put extra care into bomb-proof wind protection and rodent-proof insulation than the thickness here in Skåne.
Reuse?
Why should the old insulation be removed?
If, for some inexplicable reason, the old insulation is removed, it's better to dispose of it and buy new. It's not necessary, but it's less unpleasant to work with new insulation. In addition, there is the opportunity to buy a more high-quality insulation, i.e., with a better lambda value. It might even correspond to a couple of extra cm of standard insulation.
15 cm well wind-protected insulation is sufficient in Skåne. I would even argue that it's more important to put extra care into bomb-proof wind protection and rodent-proof insulation than the thickness here in Skåne.
Know-It-All
· Västra Götaland
· 12 287 posts
External wind protection is, as mentioned, the most important. Then as thick and high-quality insulation as can be fitted with reasonable dimensions. Often it is poorly windproofed, so the wind blows right into the insulation.
As I wrote, the old insulation is being removed due to the lack of ventilation behind it, which needs fixing, and the rafters are going to be built up to become deeper.
If the interior vapor barrier can be made completely tight everywhere with certainty, one can in principle add significantly thicker insulation. However, one typically does not want to sacrifice many cm internally, as it usually makes the space too small and cramped.
Therefore, I maintain the minimum possible thickness to avoid losing much-needed space. There are not many days (nights) per year when it is so cold here that more than about 15 cm of insulation makes any significant difference. On the other hand, it is essential for most of the year that the insulation in place is very well protected against wind and rodents.
If the old insulation is intact and fresh, then certainly it can be reused, but it's nicer to work with new insulation.
Therefore, I maintain the minimum possible thickness to avoid losing much-needed space. There are not many days (nights) per year when it is so cold here that more than about 15 cm of insulation makes any significant difference. On the other hand, it is essential for most of the year that the insulation in place is very well protected against wind and rodents.
If the old insulation is intact and fresh, then certainly it can be reused, but it's nicer to work with new insulation.