Hello,
I recently purchased an end-terrace house built in 1986 and am planning the upcoming renovation work. Now I am wondering whether I need to replace the roof insulation to improve thermal protection against heat and cold. This would be a good time since we do not yet live in the house.
It has a pitched roof that covers two floors (out of three). The attic is converted into a room and has radiators and two roof windows (Braas) on each side. The ceilings and walls are covered with wooden battens, while on the second floor the walls and ceilings are covered with drywall panels.
The construction description states:
"Plasterboard on counter battens, 10cm (4 inches) mineral wool, between joists, air space, concrete roof tiles."
A vapor barrier/retardant foil is visible.
In some areas of the attic, wooden beams have warped slightly forward and cannot be pushed back by hand. Also, some wooden paneling is missing, leaving the insulation exposed.
I have read that until the 1990s, carcinogenic mineral wool was used. Unfortunately, I do not know which type is installed in my house. Should the insulation be replaced for this reason alone?
According to the previous owner, drafts are only noticeable through the bedroom inspection hatch on the second floor. Otherwise, there is nothing unusual in winter or summer.
What do you recommend: replace or leave as is?
I recently purchased an end-terrace house built in 1986 and am planning the upcoming renovation work. Now I am wondering whether I need to replace the roof insulation to improve thermal protection against heat and cold. This would be a good time since we do not yet live in the house.
It has a pitched roof that covers two floors (out of three). The attic is converted into a room and has radiators and two roof windows (Braas) on each side. The ceilings and walls are covered with wooden battens, while on the second floor the walls and ceilings are covered with drywall panels.
The construction description states:
"Plasterboard on counter battens, 10cm (4 inches) mineral wool, between joists, air space, concrete roof tiles."
A vapor barrier/retardant foil is visible.
In some areas of the attic, wooden beams have warped slightly forward and cannot be pushed back by hand. Also, some wooden paneling is missing, leaving the insulation exposed.
I have read that until the 1990s, carcinogenic mineral wool was used. Unfortunately, I do not know which type is installed in my house. Should the insulation be replaced for this reason alone?
According to the previous owner, drafts are only noticeable through the bedroom inspection hatch on the second floor. Otherwise, there is nothing unusual in winter or summer.
What do you recommend: replace or leave as is?
A
atomic200026 Jul 2019 13:52But then I have about 1cm (0.4 inches) of ventilation space. Isn't that too little? Manufacturers recommend 3–4cm (1.2–1.6 inches).
A
atomic200026 Jul 2019 15:13I have now spoken with several suppliers. None of them have Rockwool stone wool in stock. One recommended the Knauf Insulation UNIFIT TI 135 U instead of Rockwool, and for the expensive Rockwool Intello Climate Plus and the adhesive tapes, they suggested Knauf LDS2. That sounds interesting, but now I’m unsure. Stone wool or glass wool after all?
A
atomic200026 Jul 2019 21:46I found the stone wool insulation at the hardware store, it’s in stock and not expensive. However, there are still some outstanding questions. It would be helpful if you could answer them.
Sorry for all the questions.
- I plan to use 14 + 4; is that a problem regarding the 20% rule violation?
- I can’t use 16mm because then I would only have a 1cm (0.4 inch) ventilation layer, so 14mm (0.55 inch) is correct, right?
- Which vapor barrier foil + tape + exact model do you recommend? Please specify the exact model/designation. The Knauf product is not much cheaper than the Rockwool RockTect Intello climate Plus.
- Are the tapes/adhesives from Rockwool good, or are the ones from Knauf better? Is it allowed or advisable to use tape/adhesive from one manufacturer and foil from another?
Sorry for all the questions.
You should sign up at U-Wert.net. There you can experiment a bit with issues related to condensation, among other things.
I wouldn’t worry too much about the tape and such. It just needs to stick. The important part is the wall connections. Otherwise, air will leak through there.
Regarding the exact type of vapor barrier, I can’t give you specific advice. I found my personal optimum with OSB boards. As a non-professional, I don’t know more than you do.
Personally, I wouldn’t be concerned about the 1cm (0.4 inch). But I understand if you want to be cautious.
I wouldn’t worry too much about the tape and such. It just needs to stick. The important part is the wall connections. Otherwise, air will leak through there.
Regarding the exact type of vapor barrier, I can’t give you specific advice. I found my personal optimum with OSB boards. As a non-professional, I don’t know more than you do.
Personally, I wouldn’t be concerned about the 1cm (0.4 inch). But I understand if you want to be cautious.
N
nix zu schwör27 Jul 2019 10:00Regarding the energy saving regulations, you are only subject to them if you renovate more than 10% of the building component. In your case, this does not apply, as you are not changing the roof covering at all.
This means you are only required not to make the existing condition worse. Replacing existing insulation is often pointless when it comes to the insulating properties of the material. Increasing the thickness of the rafters and adding additional insulation has already been suggested.
Summer thermal protection is generally achieved with double-layer drywall (12.5mm (0.5 inch) gypsum board). The mass is important here, so OSB alone does not provide sufficient protection, or only in combination with gypsum board. Double drywall is usually installed on a wooden frame.
This means you are only required not to make the existing condition worse. Replacing existing insulation is often pointless when it comes to the insulating properties of the material. Increasing the thickness of the rafters and adding additional insulation has already been suggested.
Summer thermal protection is generally achieved with double-layer drywall (12.5mm (0.5 inch) gypsum board). The mass is important here, so OSB alone does not provide sufficient protection, or only in combination with gypsum board. Double drywall is usually installed on a wooden frame.
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