Hello,
I am going to add insulation to both gables on the upper floor of my 1½-story house built in 1963 and wonder if I need a vapor barrier in the roof and the remaining walls or if it's enough to have it only on the gable side?
The outer wall from the outside in consists of a new sheet metal facade, wooden facade, glass wool, and wood fiberboard. The ventilation between the sheet metal and the wooden facade is good. The ventilation in the house is natural with exhaust fans in wet rooms and the kitchen.
My plan is to remove the wood fiberboard, frame 45mm from the wall for insulation between the wall and the frames and then extra insulation between the frames. Then a moisture barrier and then gypsum board.
The remaining walls don't need insulation, but the question is if I should remove the wood fiberboard, apply a moisture barrier, and also gypsum these as well?
I look forward to your thoughts on this matter.
Best regards,
Jonas
I am going to add insulation to both gables on the upper floor of my 1½-story house built in 1963 and wonder if I need a vapor barrier in the roof and the remaining walls or if it's enough to have it only on the gable side?
The outer wall from the outside in consists of a new sheet metal facade, wooden facade, glass wool, and wood fiberboard. The ventilation between the sheet metal and the wooden facade is good. The ventilation in the house is natural with exhaust fans in wet rooms and the kitchen.
My plan is to remove the wood fiberboard, frame 45mm from the wall for insulation between the wall and the frames and then extra insulation between the frames. Then a moisture barrier and then gypsum board.
The remaining walls don't need insulation, but the question is if I should remove the wood fiberboard, apply a moisture barrier, and also gypsum these as well?
I look forward to your thoughts on this matter.
Best regards,
Jonas
Mjae.
I'm not entirely clear on how your wall looks. What is "träfasad" and "plåtfasad"? Air gaps? Thicknesses?
You could place the plastic between the studs and the existing wall. That's how it is "usually" done.
For the walls you are not adding extra insulation to, you don't need to add plastic. Simply put, you place a vapor-tight layer in such walls whose thermal resistance is large compared to its vapor diffusion resistance. An inefficient ("old") wall is so poor in terms of insulation that its natural vapor diffusion resistance is sufficient without plastic.
I'm not entirely clear on how your wall looks. What is "träfasad" and "plåtfasad"? Air gaps? Thicknesses?
You could place the plastic between the studs and the existing wall. That's how it is "usually" done.
For the walls you are not adding extra insulation to, you don't need to add plastic. Simply put, you place a vapor-tight layer in such walls whose thermal resistance is large compared to its vapor diffusion resistance. An inefficient ("old") wall is so poor in terms of insulation that its natural vapor diffusion resistance is sufficient without plastic.
Hi Locke,Locke said:
By fasad, I meant panel.
The gable was originally clad in wooden paneling, then the previous owners covered it with a maintenance-free metal panel.
I have no knowledge of measurements, but judging from the airflow, it's well-ventilated between them.
Thanks for your advice regarding the walls I won't be adding insulation to, it makes my job a bit easier!
/Jonas
Covering houses with sheet metal on the cold side is a real risk construction. Now, it might be done according to all the rules on your house, and then it obviously works, but if you have the opportunity, try to find out more specific details about what the outer layers look like. How is the wood right behind the sheet metal doing?
In any case, even if you are not insulating particularly much in this case, you change the wall's properties when you add insulation. In short, you cool down the outer parts of the wall. If you now put plastic, it helps against moisture coming from inside, but there's still a bit of a warning with that.
Sheet metal facade is tricky because you have a completely sealed outer layer that also changes temperature dramatically. In a day with clear weather in spring or autumn, the sheet metal can have a temperature difference of maybe 60-70 degrees over the day.
In any case, even if you are not insulating particularly much in this case, you change the wall's properties when you add insulation. In short, you cool down the outer parts of the wall. If you now put plastic, it helps against moisture coming from inside, but there's still a bit of a warning with that.
Sheet metal facade is tricky because you have a completely sealed outer layer that also changes temperature dramatically. In a day with clear weather in spring or autumn, the sheet metal can have a temperature difference of maybe 60-70 degrees over the day.