Hello everyone,
The first offer from a developer includes an insulated basement:
- "White tank" (25cm (10 inches) waterproof reinforced concrete), with a bituminous waterproofing layer (reduces vapor diffusion)
- Perimeter insulation
- Barrier layer against rising moisture
- Underfloor heating
- Thermal insulation glazing
So, it would be the perfect basement.
The other developer, whose overall package we now prefer, states the following about the basement in the very sparse building description:
Shared (meaning for both semi-detached units) reinforced concrete slab as a waterproof construction ("white tank"). Thermal insulation on the basement ceiling within the ground floor flooring system. Thermal insulation of the slab in the stairwell area. Walls of reinforced concrete, uninsulated or with edge insulation. The basements are not intended as living spaces. Basement as a waterproof structure. Single-glazed basement windows.
There will also be a radiator in the stairwell area in the basement.
In one of the two basement rooms, laundry washing and beer brewing are planned. I intend to vent the brewing odors out through the basement window. Inside this room, I want to plaster with natural hydraulic lime.
The larger basement room is meant to be used occasionally as a recreational space. Maybe a foosball table, a couch, possibly a home cinema setup.
The building description states that condensation cannot be ruled out under unfavorable weather conditions. That doesn't sound very good to me. Honestly, it also doesn’t seem state-of-the-art, but that might just be my impression.
The basement room with the heat transfer station (district heating) will be mechanically ventilated according to the building description. What does that mean exactly? What should one imagine? Wouldn’t that rather bring in high humidity if warm outside air is pulled in during summer? Or could this ventilation even help remove the vapors produced during brewing in that room?
Now my request for help:
What measures can make the basement suitable for living spaces after all?
Is perimeter insulation on the walls sufficient?
Is adding interior insulation later advisable?
What do you think about the insulation of the slab in the stairwell area as described? From the inside? Could this insulation potentially be extended into one or two other rooms as well?
Regarding the laundry and brewing room: Do you see differences in mold risk between insulated and uninsulated basements in connection with water vapor?
Best regards
Ricard0
The first offer from a developer includes an insulated basement:
- "White tank" (25cm (10 inches) waterproof reinforced concrete), with a bituminous waterproofing layer (reduces vapor diffusion)
- Perimeter insulation
- Barrier layer against rising moisture
- Underfloor heating
- Thermal insulation glazing
So, it would be the perfect basement.
The other developer, whose overall package we now prefer, states the following about the basement in the very sparse building description:
Shared (meaning for both semi-detached units) reinforced concrete slab as a waterproof construction ("white tank"). Thermal insulation on the basement ceiling within the ground floor flooring system. Thermal insulation of the slab in the stairwell area. Walls of reinforced concrete, uninsulated or with edge insulation. The basements are not intended as living spaces. Basement as a waterproof structure. Single-glazed basement windows.
There will also be a radiator in the stairwell area in the basement.
In one of the two basement rooms, laundry washing and beer brewing are planned. I intend to vent the brewing odors out through the basement window. Inside this room, I want to plaster with natural hydraulic lime.
The larger basement room is meant to be used occasionally as a recreational space. Maybe a foosball table, a couch, possibly a home cinema setup.
The building description states that condensation cannot be ruled out under unfavorable weather conditions. That doesn't sound very good to me. Honestly, it also doesn’t seem state-of-the-art, but that might just be my impression.
The basement room with the heat transfer station (district heating) will be mechanically ventilated according to the building description. What does that mean exactly? What should one imagine? Wouldn’t that rather bring in high humidity if warm outside air is pulled in during summer? Or could this ventilation even help remove the vapors produced during brewing in that room?
Now my request for help:
What measures can make the basement suitable for living spaces after all?
Is perimeter insulation on the walls sufficient?
Is adding interior insulation later advisable?
What do you think about the insulation of the slab in the stairwell area as described? From the inside? Could this insulation potentially be extended into one or two other rooms as well?
Regarding the laundry and brewing room: Do you see differences in mold risk between insulated and uninsulated basements in connection with water vapor?
Best regards
Ricard0
Ricard0 schrieb:
Shared (meaning for both semi-detached units) reinforced concrete slab as a waterproof concrete structure (watertight basement). Thermal insulation on the basement ceiling within the ground floor floor construction. Thermal insulation of the slab in the stairwell area.
Walls made of reinforced concrete, uninsulated or with partial insulation. The basements are not living spaces. Basement as a waterproof concrete structure.
Single-glazed basement windows.
Best regards
Ricardo It’s great if the plot suits you – but the basement doesn’t sound very good. Sound transmission with a shared slab would be a deal breaker for me.
When buying an existing property, you consider both the house and the land – you should do the same with a developer. And if the house is poorly built, even beautiful surroundings won’t help.
Hello Wastl,
the basement does not sound very promising according to the current plans, unfortunately. That’s why I’m considering whether it can be reasonably improved with some modifications, for example, by using perimeter insulation on the basement walls.
The shared foundation slab should cause minimal noise disturbances, based on my research. After all, the upper floors are separated by an expansion joint and consist of 17.5cm (7 inches) thick masonry. I’m hoping for calcium silicate bricks, although I haven’t been able to confirm this exactly yet.
Such a construction is generally recommended by the calcium silicate brick industry and meets the enhanced sound insulation requirements according to Supplement 1 of DIN 4109 (i.e. at least 67dB attenuation). According to the builder’s specifications, this level of soundproofing will be achieved.
Another idea now is to ask about installing a controlled ventilation system for the entire house including the basement, in addition to the perimeter insulation. This is intended to ensure air exchange and help prevent moisture problems.
the basement does not sound very promising according to the current plans, unfortunately. That’s why I’m considering whether it can be reasonably improved with some modifications, for example, by using perimeter insulation on the basement walls.
The shared foundation slab should cause minimal noise disturbances, based on my research. After all, the upper floors are separated by an expansion joint and consist of 17.5cm (7 inches) thick masonry. I’m hoping for calcium silicate bricks, although I haven’t been able to confirm this exactly yet.
Such a construction is generally recommended by the calcium silicate brick industry and meets the enhanced sound insulation requirements according to Supplement 1 of DIN 4109 (i.e. at least 67dB attenuation). According to the builder’s specifications, this level of soundproofing will be achieved.
Another idea now is to ask about installing a controlled ventilation system for the entire house including the basement, in addition to the perimeter insulation. This is intended to ensure air exchange and help prevent moisture problems.
B
Bauexperte7 Dec 2015 11:46Hello Ricardo,
Have you at least gathered information about your preferred provider? Have you considered bringing in external expertise for the house-building adventure?
Regards, Bauexperte
Ricard0 schrieb:No. A plot can never be so nice that I would willingly take on unpredictable additional construction issues—and without necessity.
One developer offers a better house but includes a small, shoebox-sized plot, while the other, with the "worse" house, offers a fantastic corner lot almost twice as large. That also explains why we tend to prefer it.
Ricard0 schrieb:Strange approach?! We have a building description that applies to all construction projects; of course, it can be expanded with supplementary agreements. What a logistical effort it would be to write a separate building description for each project.
So far, the preliminary building description is only two DIN A4 pages. Marketing will only start at the beginning of next year. However, discussions are already underway to secure some buffer time before the KfW-70 subsidy expires. The building description is, of course, intended to be expanded and clarified.
Have you at least gathered information about your preferred provider? Have you considered bringing in external expertise for the house-building adventure?
Regards, Bauexperte
Hello construction expert,
that all makes sense – the building specification is very general, and what is included doesn’t really inspire confidence. But the plot of land... truly outstanding (adjacent to parkland on two sides, twice the size of the competitor’s lot, southwest orientation). However, nothing has been decided yet.
The developer is a company that has been in business for over 100 years, with the city as a significant majority shareholder. Many projects have already been completed by this company in Cologne. I have heard a lot of praise as well as some criticisms regarding their work.
The general contractor (or main contractor, I’m not entirely sure) has also completed many large projects. For example, I work in a building they delivered.
We definitely want to hire a construction consultant to support us. However, with the current building specification, I don’t want to commission anyone to review it yet, since it contains too little detail.
At least now we can appreciate the building specification and planned execution of the competing developer.
Best regards
Ricard0
that all makes sense – the building specification is very general, and what is included doesn’t really inspire confidence. But the plot of land... truly outstanding (adjacent to parkland on two sides, twice the size of the competitor’s lot, southwest orientation). However, nothing has been decided yet.
The developer is a company that has been in business for over 100 years, with the city as a significant majority shareholder. Many projects have already been completed by this company in Cologne. I have heard a lot of praise as well as some criticisms regarding their work.
The general contractor (or main contractor, I’m not entirely sure) has also completed many large projects. For example, I work in a building they delivered.
We definitely want to hire a construction consultant to support us. However, with the current building specification, I don’t want to commission anyone to review it yet, since it contains too little detail.
At least now we can appreciate the building specification and planned execution of the competing developer.
Best regards
Ricard0
B
Bauexperte7 Dec 2015 12:15Hello Ricardo,
That alone means nothing at first. Why? A few weeks ago, I responded to a tender simply because the purchasers wouldn’t leave me alone. It concerns 2 blocks of 3 terraced houses each, with another 200 housing units tied to the contract award. Of course, the people involved thought this incentive would affect our bid price; wrong. So I hoped the matter was settled. Wrong again… hope and wait…
Anyway – when I read through the room schedule, I almost couldn’t believe how minimal it was. If I translate this based on your scarce details about the preferred provider, in my opinion, you can safely assume that you will have to purchase many costly extras. Because clients of larger housing units primarily focus on their return on investment, not on reasonable features.
If you take this to heart, consult an external expert, and your budget matches your dream home: all good. Otherwise, you should stay away from the offer.
Just my 2 cents
Regards, Bauexperte
Ricard0 schrieb:
The developer is a company that has been around for over 100 years, with the city as its majority shareholder. They have completed many projects in Cologne. I have heard a lot of praise as well as some criticisms.
The general contractor (or main contractor, I’m not quite sure) has also completed many large projects. For example, I work in one of their buildings.
That alone means nothing at first. Why? A few weeks ago, I responded to a tender simply because the purchasers wouldn’t leave me alone. It concerns 2 blocks of 3 terraced houses each, with another 200 housing units tied to the contract award. Of course, the people involved thought this incentive would affect our bid price; wrong. So I hoped the matter was settled. Wrong again… hope and wait…
Anyway – when I read through the room schedule, I almost couldn’t believe how minimal it was. If I translate this based on your scarce details about the preferred provider, in my opinion, you can safely assume that you will have to purchase many costly extras. Because clients of larger housing units primarily focus on their return on investment, not on reasonable features.
If you take this to heart, consult an external expert, and your budget matches your dream home: all good. Otherwise, you should stay away from the offer.
Just my 2 cents
Regards, Bauexperte
Even when dealing with a well-established developer with a long-standing reputation, building specifications should be written professionally and in sufficient detail to provide knowledgeable inspectors with clear and comprehensive information. They should include thorough descriptions of the structural shell and interior construction / technical installations, including precise material specifications and well-founded statements on sound insulation, thermal insulation, moisture protection, and if applicable, fire protection. As a prospective homeowner, I would not want to rely on basic technical information, attractive pictures, and promotional texts alone.
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