Hello everyone,
a general contractor we are currently considering offers the basement with
Quote:
Exterior basement walls, instead of being built as masonry, alternatively
according to DIN 18195, Part 6, as a waterproof structure of usage class A,
according to the DAfStb guideline
“Waterproof concrete structures” (WU guideline)
designed for exposure to occasionally rising
seepage water (exposure class 1) up to a maximum of 15 cm (6 inches)
below the bottom edge of the window wells
Does this mean that it is a waterproof (white) tank basement, or is the basement just sealed from the outside?
I would appreciate it if someone could clarify this for me.
Thanks!
a general contractor we are currently considering offers the basement with
Quote:
Exterior basement walls, instead of being built as masonry, alternatively
according to DIN 18195, Part 6, as a waterproof structure of usage class A,
according to the DAfStb guideline
“Waterproof concrete structures” (WU guideline)
designed for exposure to occasionally rising
seepage water (exposure class 1) up to a maximum of 15 cm (6 inches)
below the bottom edge of the window wells
Does this mean that it is a waterproof (white) tank basement, or is the basement just sealed from the outside?
I would appreciate it if someone could clarify this for me.
Thanks!
B
Bauexperte13 Mar 2016 18:52@muttley
The term "White Tank" is being misused nowadays. It originally comes from the railway sector and referred specifically to a basement in a basement system.
What the general contractor offered you, however, corresponds to the current use of the term and thus to what you understand by "White Tank."
Costa’s explanation is therefore not correct in this context; at least it is incomplete.
Regards, Bauexperte
Bauexperte
The term "White Tank" is being misused nowadays. It originally comes from the railway sector and referred specifically to a basement in a basement system.
What the general contractor offered you, however, corresponds to the current use of the term and thus to what you understand by "White Tank."
Costa’s explanation is therefore not correct in this context; at least it is incomplete.
Regards, Bauexperte
Bauexperte
Hello,
From the wording, this sounds like Büttner, right? We are building with them as well. Basically, they are a good construction company, but they’re not exactly charity… In other words, they want to make a profit too.
A few pointers:
The important clause is:
"Max. 15 cm (6 inches) below the bottom edge of the light wells"
This means for you that the reinforcement in the concrete above this limit is _no longer_ waterproof concrete (WU) tank reinforcement.
Explanation:
For waterproof concrete, more reinforcement is required, which is the actual extra cost. The additional cost of the waterproof concrete itself compared to normal concrete is negligible.
Above the light wells, the same concrete is used, but not the necessary reinforcement. So, if you really need a waterproof tank up to the basement ceiling, that’s where the first extra costs for reinforcement come in.
But unfortunately, that’s not all; you’ll also need drainage for the light wells or waterproof light wells that can withstand water pressure. And depending on your preferences, flood-resistant basement windows are also not a bad idea.
That can quickly add up to around 4,000–8,000 Euro in additional costs.
To be fair, this probably applies to most construction companies!
If you can do without basement windows because it’s purely a technical, storage, or workshop basement, you can save a lot of money here. However, a controlled ventilation system is then mandatory.
Further, if it really is Büttner (if not, just ignore the next paragraph):
During the construction review, they will want your approval for the following approach:
"Deviation from the standard DIN execution of the floor slab in waterproof construction with a top PE foil as a vapor barrier instead of a welded membrane"
In other words, they want to replace the normally required welded membrane with a simple PE foil. This saves them about 15–17 Euro per square meter, but increases your risk of moisture in the basement. Absolutely reject this and don’t even start discussing it!
By the way:
Apparently, “WU tank” is not really a protected term. According to my neighbor (a project manager at one of the large German construction companies), no professional really uses this term because it isn’t clearly defined. Whether he’s right or not, I can’t judge, but the statement has made me more cautious.
Best regards,
Andreas
From the wording, this sounds like Büttner, right? We are building with them as well. Basically, they are a good construction company, but they’re not exactly charity… In other words, they want to make a profit too.
A few pointers:
The important clause is:
"Max. 15 cm (6 inches) below the bottom edge of the light wells"
This means for you that the reinforcement in the concrete above this limit is _no longer_ waterproof concrete (WU) tank reinforcement.
Explanation:
For waterproof concrete, more reinforcement is required, which is the actual extra cost. The additional cost of the waterproof concrete itself compared to normal concrete is negligible.
Above the light wells, the same concrete is used, but not the necessary reinforcement. So, if you really need a waterproof tank up to the basement ceiling, that’s where the first extra costs for reinforcement come in.
But unfortunately, that’s not all; you’ll also need drainage for the light wells or waterproof light wells that can withstand water pressure. And depending on your preferences, flood-resistant basement windows are also not a bad idea.
That can quickly add up to around 4,000–8,000 Euro in additional costs.
To be fair, this probably applies to most construction companies!
If you can do without basement windows because it’s purely a technical, storage, or workshop basement, you can save a lot of money here. However, a controlled ventilation system is then mandatory.
Further, if it really is Büttner (if not, just ignore the next paragraph):
During the construction review, they will want your approval for the following approach:
"Deviation from the standard DIN execution of the floor slab in waterproof construction with a top PE foil as a vapor barrier instead of a welded membrane"
In other words, they want to replace the normally required welded membrane with a simple PE foil. This saves them about 15–17 Euro per square meter, but increases your risk of moisture in the basement. Absolutely reject this and don’t even start discussing it!
By the way:
Apparently, “WU tank” is not really a protected term. According to my neighbor (a project manager at one of the large German construction companies), no professional really uses this term because it isn’t clearly defined. Whether he’s right or not, I can’t judge, but the statement has made me more cautious.
Best regards,
Andreas
Hello andimann,
yes, that was exactly the company. We have now also received the offer. If we wanted the higher quality version, it would have meant an additional cost of €9,000. So this company is out. Another general contractor we are seriously considering offers a complete foundation shell and is overall cheaper.
The welfare aspect is probably true. You also have to keep in mind that many people want to be kept on the company’s payroll...
yes, that was exactly the company. We have now also received the offer. If we wanted the higher quality version, it would have meant an additional cost of €9,000. So this company is out. Another general contractor we are seriously considering offers a complete foundation shell and is overall cheaper.
The welfare aspect is probably true. You also have to keep in mind that many people want to be kept on the company’s payroll...
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