Hi everyone,
We had a really exhausting day today.
We had two meetings at the prefabricated house center in Mannheim.
In the morning, we visited Keitel-Haus, and in the afternoon, Hanse Haus.
Our problem is: after meeting with Keitel-Haus, we thought we finally had clarity. But Hanse claims exactly the opposite.
At Keitel-Haus, this was our second long discussion, and this time we went into detail with a precise written quote and detailed descriptions of the individual building materials.
Now to the different statements, and we would appreciate your opinions as well.
You have the experience and are independent.
Exterior wall:
Keitel-Haus: vapor-permeable wall WITHOUT a vapor barrier (vapor retarder).
Including:
60mm (2.4 inches) wood fiber insulation board
200mm (7.9 inches) timber frame construction
200mm (7.9 inches) mineral fiber insulation
Wall thickness 29.2cm (11.5 inches)
Hanse: vapor-permeable wall WITH vapor retarder
Including:
150mm (5.9 inches) thermal insulation, thermal conductivity class 032
8mm (0.3 inches) OSB board
125mm (4.9 inches) timber frame construction (with mineral insulation)
8mm (0.3 inches) OSB board
vapor-permeable vapor retarder fleece
12.5mm (0.5 inches) gypsum board
So,
Keitel-Haus says: We build a proper vapor-permeable wall, so without any vapor retarders. This allows moisture to really escape outside, preventing mold growth.
Hanse says: That’s nonsense, there are no houses that can "breathe". We have a vapor retarder because we want to hold back water vapor, i.e., moisture. We don’t want it to enter the wall, as it would cause damage. Without a barrier, mold would eventually develop.
What is correct here?
Topic 2
Heating technology / ventilation:
Keitel-Haus:
They considered our wishes and said that while they think controlled residential ventilation is good, they do not recommend controlled ventilation with heat recovery. I don’t remember exactly why, but there was a lengthy explanation. Anyway, probably because of underfloor heating, we wanted a heat pump.
Hanse:
They tried to persuade us to get a different kind of heat pump and insisted it would be better to have controlled ventilation WITH heat recovery.
It would save energy, and windows can still be opened (which we want, especially at night while sleeping and sometimes in summer).
If I remember correctly, I recently read only negative things about that kind of heat pump, and that it would financially disadvantage us.
Hanse says: Nonsense. If the house is built properly and the system is installed correctly, this kind of heat pump is best, and they can ensure it is the most cost-effective.
Topic 3
KfW 40/55 standards
Keitel-Haus:
KfW 55 is optimal and can be achieved without problems according to our requirements (photovoltaics, underfloor heating, heat pump, vapor-permeable wall).
KfW 40 requires too much effort and is much too expensive. The savings wouldn’t justify it.
Hanse:
KfW 40 or better yet Passive House, since from 2020 Passive House standard is mandatory anyway.
The difference from KfW 55 to KfW 40 would only be about €9000 and corresponds to additional insulation under the slab and roof. No extra technology would be needed, and the savings would be enormous!
Their walls already meet KfW 40 as standard.
Topic 4:
Exterior wall insulation
Keitel-Haus builds with wood fiber insulation board. Styrofoam (EPS) is standard but not recommended because it is vapor-tight. That’s why they offer a better "open" wall.
I know Styrofoam is extremely poor in fire performance. I don’t like it at all.
Hanse:
I had no clear answer; I couldn’t really get details. They just said Styrofoam is not so bad, and their thermal insulation contains some graphite.
It seemed to me like Styrofoam with graphite additives or something similar.
I know, lots of questions again.
I have already spent many hours reading but still don’t feel much wiser.
These topics are very complex and sometimes a bit beyond me.
From the feeling we have, we would build with Keitel-Haus.
The Hanse representative was arrogant and "aggressive." I even almost argued with him because he was unwilling to discuss most points, including providing a written offer. He said he only bothers if he knows you really want to build with them. For me, a comparison makes no sense without different offers and service descriptions to compare.
We also looked at Fingerhut, but after 6 weeks they still haven’t provided an offer. So that’s a no-go for us. The "salesperson" seems to prefer working his side job (entertainer).
Rensch-Haus gave us many verbal promises that everything would be possible (of course, for extra money, everything is possible), but 90% of what should have been standard was not in the service description.
We had a really exhausting day today.
We had two meetings at the prefabricated house center in Mannheim.
In the morning, we visited Keitel-Haus, and in the afternoon, Hanse Haus.
Our problem is: after meeting with Keitel-Haus, we thought we finally had clarity. But Hanse claims exactly the opposite.
At Keitel-Haus, this was our second long discussion, and this time we went into detail with a precise written quote and detailed descriptions of the individual building materials.
Now to the different statements, and we would appreciate your opinions as well.
You have the experience and are independent.
Exterior wall:
Keitel-Haus: vapor-permeable wall WITHOUT a vapor barrier (vapor retarder).
Including:
60mm (2.4 inches) wood fiber insulation board
200mm (7.9 inches) timber frame construction
200mm (7.9 inches) mineral fiber insulation
Wall thickness 29.2cm (11.5 inches)
Hanse: vapor-permeable wall WITH vapor retarder
Including:
150mm (5.9 inches) thermal insulation, thermal conductivity class 032
8mm (0.3 inches) OSB board
125mm (4.9 inches) timber frame construction (with mineral insulation)
8mm (0.3 inches) OSB board
vapor-permeable vapor retarder fleece
12.5mm (0.5 inches) gypsum board
So,
Keitel-Haus says: We build a proper vapor-permeable wall, so without any vapor retarders. This allows moisture to really escape outside, preventing mold growth.
Hanse says: That’s nonsense, there are no houses that can "breathe". We have a vapor retarder because we want to hold back water vapor, i.e., moisture. We don’t want it to enter the wall, as it would cause damage. Without a barrier, mold would eventually develop.
What is correct here?
Topic 2
Heating technology / ventilation:
Keitel-Haus:
They considered our wishes and said that while they think controlled residential ventilation is good, they do not recommend controlled ventilation with heat recovery. I don’t remember exactly why, but there was a lengthy explanation. Anyway, probably because of underfloor heating, we wanted a heat pump.
Hanse:
They tried to persuade us to get a different kind of heat pump and insisted it would be better to have controlled ventilation WITH heat recovery.
It would save energy, and windows can still be opened (which we want, especially at night while sleeping and sometimes in summer).
If I remember correctly, I recently read only negative things about that kind of heat pump, and that it would financially disadvantage us.
Hanse says: Nonsense. If the house is built properly and the system is installed correctly, this kind of heat pump is best, and they can ensure it is the most cost-effective.
Topic 3
KfW 40/55 standards
Keitel-Haus:
KfW 55 is optimal and can be achieved without problems according to our requirements (photovoltaics, underfloor heating, heat pump, vapor-permeable wall).
KfW 40 requires too much effort and is much too expensive. The savings wouldn’t justify it.
Hanse:
KfW 40 or better yet Passive House, since from 2020 Passive House standard is mandatory anyway.
The difference from KfW 55 to KfW 40 would only be about €9000 and corresponds to additional insulation under the slab and roof. No extra technology would be needed, and the savings would be enormous!
Their walls already meet KfW 40 as standard.
Topic 4:
Exterior wall insulation
Keitel-Haus builds with wood fiber insulation board. Styrofoam (EPS) is standard but not recommended because it is vapor-tight. That’s why they offer a better "open" wall.
I know Styrofoam is extremely poor in fire performance. I don’t like it at all.
Hanse:
I had no clear answer; I couldn’t really get details. They just said Styrofoam is not so bad, and their thermal insulation contains some graphite.
It seemed to me like Styrofoam with graphite additives or something similar.
I know, lots of questions again.
I have already spent many hours reading but still don’t feel much wiser.
These topics are very complex and sometimes a bit beyond me.
From the feeling we have, we would build with Keitel-Haus.
The Hanse representative was arrogant and "aggressive." I even almost argued with him because he was unwilling to discuss most points, including providing a written offer. He said he only bothers if he knows you really want to build with them. For me, a comparison makes no sense without different offers and service descriptions to compare.
We also looked at Fingerhut, but after 6 weeks they still haven’t provided an offer. So that’s a no-go for us. The "salesperson" seems to prefer working his side job (entertainer).
Rensch-Haus gave us many verbal promises that everything would be possible (of course, for extra money, everything is possible), but 90% of what should have been standard was not in the service description.
A vapor retarder (not a vapor barrier, as these are two different things) is necessary if you don’t want your wall to eventually rot away (although it is possible to build without one, there is absolutely no margin for error, and you can hardly expect construction to be flawless).
Breathable houses/walls do not exist—this is a marketing gimmick, as real as Santa Claus.
A mechanical ventilation system without heat recovery is outdated technology (still better than nothing), but nowadays I would only consider systems with heat recovery and an enthalpy exchanger.
An air-to-air heat pump works great in Spain... in Germany, it is basically a money pit, even though some people will say otherwise... anyone knows that a “normal” air conditioner in the house is more a luxury with high installation and operating costs. An air-to-air heat pump is essentially an air conditioner that just produces heat.
So if you want a heat pump for your house, it should be at least an air-to-water heat pump.
You have concerns about the polystyrene and its fire behavior??? But you want to build a wooden house??????
Breathable houses/walls do not exist—this is a marketing gimmick, as real as Santa Claus.
A mechanical ventilation system without heat recovery is outdated technology (still better than nothing), but nowadays I would only consider systems with heat recovery and an enthalpy exchanger.
An air-to-air heat pump works great in Spain... in Germany, it is basically a money pit, even though some people will say otherwise... anyone knows that a “normal” air conditioner in the house is more a luxury with high installation and operating costs. An air-to-air heat pump is essentially an air conditioner that just produces heat.
So if you want a heat pump for your house, it should be at least an air-to-water heat pump.
You have concerns about the polystyrene and its fire behavior??? But you want to build a wooden house??????
305er schrieb:
Exterior Wall:
Keitel house: vapor-permeable wall WITHOUT a vapor barrier (vapor retarder).
Includes, among others:
60mm wood fiber insulation board
200mm timber frame construction
200mm mineral fiber insulation
Wall thickness 29.2cm (11.5 inches)
Our wall construction is basically the same as you described (although we use hemp instead of mineral wool), and in our case, a vapor retarder is installed between the OSB and the gypsum board.
Bautraum201518 Nov 2015 07:48Vapor barrier or vapor retarder?
We also visited Keitel-Haus and were ready to build with them. All the others seemed like quacks! Keitel-Haus has building biologists on board who have studied the subject thoroughly... they really know their stuff, and thanks to our civil engineers in the family, I know they weren’t talking nonsense. However, if anything, I would recommend hemp insulation. It can transport moisture much better due to the fiber structure.
In the end, we didn’t build with Keitel-Haus because it was more expensive than the contractor offering monolithic brick wall construction. So, we are going with a solid masonry house. That said, I still find Keitel-Haus very appealing.
We also visited Keitel-Haus and were ready to build with them. All the others seemed like quacks! Keitel-Haus has building biologists on board who have studied the subject thoroughly... they really know their stuff, and thanks to our civil engineers in the family, I know they weren’t talking nonsense. However, if anything, I would recommend hemp insulation. It can transport moisture much better due to the fiber structure.
In the end, we didn’t build with Keitel-Haus because it was more expensive than the contractor offering monolithic brick wall construction. So, we are going with a solid masonry house. That said, I still find Keitel-Haus very appealing.
All others are charlatans, very professional attitude. And because you hired a building biologist, you think you have it all figured out. Then I could start my own business as a home builder. Sorry, but these are arguments that just make me shake my head. There are many good home construction companies, including those that specialize in solid or masonry houses.
Bautraum201518 Nov 2015 07:54Not fully awake yet, or why are you being so difficult right away?
Everyone else we dealt with, from our point of view, were charlatans!! We always had experts present during the discussions. Of course, there are many good companies on the market...? Did I question that? It’s just that none of them were included in our ranking.
Everyone else we dealt with, from our point of view, were charlatans!! We always had experts present during the discussions. Of course, there are many good companies on the market...? Did I question that? It’s just that none of them were included in our ranking.
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