ᐅ Roof insulation made of 100mm thick rigid polyurethane (PU) foam

Created on: 21 Oct 2019 09:19
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Ankeffm
Hello everyone,
I urgently need some advice and tips regarding roof insulation.
We plan to have our roof replaced next year. Now, the topic is roof insulation. Our roofer recommended the following:
Polyurethane (PU) rigid foam, 100mm (4 inches) thick // Type: puren Protect N 023.
This would be an insulation installed above the rafters (i.e., external insulation). However, I have read in forums and other sources that sound insulation with this type of material often falls short. The noise level can sometimes be quite high. This is partly due to the boards themselves (as they apparently expand and contract, especially at night) and also because the boards do not provide good soundproofing.
We would really like the space under the roof to be more comfortable in summer and, of course, quieter—or at least that outside noise levels are bearable.
Can you give us advice on the best way to insulate a roof like this? Has anyone had experience with this type: puren Protect N 023?
Please help... THANK YOU!!!
Best regards, Anke
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boxandroof
25 Oct 2019 16:36
It always makes sense to familiarize yourself with the subject. You can view it negatively or as a challenge.

The architect can assess the local conditions, which is especially useful in older buildings, and the money is usually well spent. A dedicated and experienced craftsman can, of course, do this as well.
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Nordlys
26 Oct 2019 00:12
When I request a new roof and thermal insulation, the roofer provides proper advice. But when I ask for a new roof with thermal insulation that offers both heat protection and good soundproofing, his advice is completely off. What exactly was he asked?
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Farilo
26 Oct 2019 00:20
You may be right.

However, I personally have a completely different approach to service. When I hear the term "expert," I expect that person to have comprehensive knowledge of their field. I wouldn’t let a client head for trouble just because they only wanted a "warm" environment in winter and never mentioned "cool in summer."

But that’s just how it is in Germany. There’s nothing you can do about it. The term "service desert Germany" didn’t come out of nowhere. And what "Made in Germany" is worth, we’ve all learned by now, especially since the diesel scandal...

@Dachausbauer : Thanks for the detailed explanation
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Nordlys
26 Oct 2019 09:25
I am less pessimistic about this, also because I often have good experiences. In my opinion, it is more effective to seek advice from companies that combine roofer, plumber, and carpenter skills in one firm, meaning they fully handle the entire roof system. This way, the advice is more comprehensive and not so narrowly focused on my specific trade or billing. K.
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Ankeffm
26 Oct 2019 12:01
Hello everyone,
Thanks to all who are contributing. I think that’s really great of you.
We will have our roof done, yes... For us, it was important that it is well insulated. That’s why we were recommended the polyurethane (PU) boards.
However, my internet research showed that while these boards are good, they are not as effective when it comes to thermal and sound insulation.
So I continued researching and reading. Now my opinion is that wood fiber boards are better for sound and heat protection, mainly because of their mass. Thermal insulation is of course also very good with them. Additionally, we plan to install insulation between the rafters due to phase shifts. We haven’t contacted an architect yet.
I don’t think they can offer much more (or something completely new). The options are basically over-rafter insulation, under-rafter insulation, and insulation between rafters, all using different materials. I think wood fiber boards are definitely better.
Take some time to look into this topic. You really have to do a lot of reading. By now, I even understand this U-value calculator.
Pinky030126 Oct 2019 13:16
Have you had a chance to check the KfW website yet? Are you able to receive a grant?