ᐅ Poroton 36.5 or 42.5 with perlite or mineral wool insulation
Created on: 17 Feb 2021 14:00
F
Freiburger2020
Hello everyone,
we are uncertain whether to go with a monolithic KfW40 or just KfW55 standard.
That means choosing between the Poroton T7 36.5cm (14.4 inches) or the 42.5cm (16.7 inches) insulated brick.
We are also undecided between using perlite or mineral wool insulation. I hope to get some input based on experience. The building contractor is not giving clear advice, with different opinions on which is better or worse.
Since we are building two residential units, we will receive double KfW subsidies, so the repayment grant is a strong argument in favor of KfW40 and the 42.5cm (16.7 inches) brick.
On the other hand, there is the actual loss of space with the 42.5cm (16.7 inches) brick compared to the 36.5cm (14.4 inches) one, and the fear that heating costs with the 36.5cm (14.4 inches) brick might become overwhelming after a few years.
We definitely want a solar system, which again supports going for the KfW40+ standard and the 42.5cm (16.7 inches) brick.
We look forward to your opinions.
we are uncertain whether to go with a monolithic KfW40 or just KfW55 standard.
That means choosing between the Poroton T7 36.5cm (14.4 inches) or the 42.5cm (16.7 inches) insulated brick.
We are also undecided between using perlite or mineral wool insulation. I hope to get some input based on experience. The building contractor is not giving clear advice, with different opinions on which is better or worse.
Since we are building two residential units, we will receive double KfW subsidies, so the repayment grant is a strong argument in favor of KfW40 and the 42.5cm (16.7 inches) brick.
On the other hand, there is the actual loss of space with the 42.5cm (16.7 inches) brick compared to the 36.5cm (14.4 inches) one, and the fear that heating costs with the 36.5cm (14.4 inches) brick might become overwhelming after a few years.
We definitely want a solar system, which again supports going for the KfW40+ standard and the 42.5cm (16.7 inches) brick.
We look forward to your opinions.
andimann schrieb:
Hello,
is the Poroton T7 36.5 also available as a filled block? The unfilled ones are so delicate that I would be very concerned about sound insulation.
I spent a lot of time thinking about it back then. From today’s perspective, I consider this issue to be greatly overrated. Today, I would simply build with 17 or 24 cm (7 or 9.5 inches) calcium silicate blocks and put ETICS (external thermal insulation composite system) on the outside. Soundproofing and summer heat protection are much more important than saving a few percent on heating costs.
Best regards,
Andreas You’re always wiser in hindsight… and there are pros and cons for everything. Having plastic on the walls isn’t very pleasant, and I wouldn’t do it without a ventilation system…
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nordanney17 Feb 2021 15:33Snowy36 schrieb:
Having plastic on the wall isn’t very nice and I wouldn’t do it without a ventilation system....ETICS (not all of it is plastic) has nothing to do with a ventilation system. A monolithic structure is just as airtight as one with ETICS. Ventilation system is always necessary!Sand-lime brick with external thermal insulation composite system (ETICS) or insulated masonry with filled bricks. Definitely avoid unfilled bricks, as they are the worst option (unfortunately still often sold in the south due to poor advice and price, we also used them and regret it). The difference between 36.5cm (14.5 inches) and 42.5cm (16.7 inches) thickness for thermal insulation doesn’t matter at all—you won’t notice any difference later in your heating costs.
Personally, I would only choose 36.5cm (14.5 inches) filled with perlite. Mineral wool isn’t much worse either; this is just based on acquaintances’ experience. They used perlite and are very satisfied.
Personally, I would only choose 36.5cm (14.5 inches) filled with perlite. Mineral wool isn’t much worse either; this is just based on acquaintances’ experience. They used perlite and are very satisfied.
nordanney schrieb:
ETICS (not everything is plastic) has nothing to do with a ventilation system. A monolithic structure is just as airtight as one with ETICS. Always use a ventilation system!Well, you also have to keep an eye on the costs... I think sand-lime brick + ETICS + controlled mechanical ventilation is the most expensive solution.
My neighbor therefore left out the controlled mechanical ventilation.
If I have to leave that out, then I don’t want ETICS but prefer bricks instead...
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nordanney17 Feb 2021 15:48Snowy36 schrieb:
If I have to leave them out, then I don’t want EIFS but prefer bricks... That’s what your gut says, not your mind 😉.
I would rather skip another small detail and install a decentralized ventilation system. 350€ per unit and only one power cable plus a core drill hole. That should always be included in new builds.
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