Trekrub
2019-05-14 21:17:44
- #1
Our house has a strip foundation that does not protrude beyond the basement wall, i.e., there is no cove. It rests on a 22 m thick layer of glacial clay/marl (Teltow Plateau) with perched water (but only if it rains heavily and for a long time, last time in 2017). The basement wall now has a new plaster layer made of cove plaster, above that a 4 mm thick bitumen coating with embedded fiberglass fleece, and then a 6 cm perimeter insulation. The perimeter insulation will still be outfitted with so-called drainage mats (dimpled sheets coated with foil and drainage fleece).
DIN 4095 for drainage specifies that especially for houses on clay soil, drainage is recommended. Therefore, I want to install such a system in addition, since the house will already be excavated. The drainage pipe is to lie on about 10 cm of gravel. In our clay, water hardly percolates.
With incoming water, 10 cm of water could constantly stand in the gravel bed at the strip foundation under the drainage pipe.
To counter this, I want to do the following:
The 0.5 m wide drainage trench has a 0.5% slope towards the corner of the house. A maintenance shaft is to be placed there. Furthermore, the drainage trench has about a 2% slope away from the house. Now I want to lay a strip of fleece in the drainage trench and on top of it a strip of pond liner (0.8 m wide, 0.5 mm thick) running continuously up to the maintenance shaft. This should be laid about 20-30 cm up along the basement wall and extend to the maintenance shaft. At this point, the maintenance shaft will have holes drilled into the pond liner and be wrapped in drainage fleece.
The aforementioned drainage mat on the basement wall should extend over the pond liner about 10 cm into the drainage trench bottom. Then drainage fleece is laid in the trench, and into this the gravel packing with the drainage pipe is placed.
Water arriving at the wall should thus be guided via the drainage mat onto the pond liner into the gravel bed and, if it does not find its way into the drainage pipe, flow on the pond liner from there to and into the maintenance shaft.
Question 1: What do you think of this solution?
Two further questions:
To still have as little water as possible standing on the pond liner, I want to additionally place the drainage pipe on a thinner gravel bed or even directly on the pond liner (or the drainage fleece) on the trench bottom. I would also like to lay the pipe at the side of the trench at the lowest point of the trench away from the house. Also conceivable would be to pull the pond liner up about 10 cm on the drainage trench wall on the side away from the house, so that a sort of trough made of pond liner (which is higher at the basement wall) would be created.
Three related questions:
Question 2: Drainage pipe on 3-5 cm of gravel or directly on the bottom?
Question 3: Drainage pipe on the side of the trench (maximum distance from the house, lowest point) or in the middle of the trench?
Question 4: Should the pond liner also be pulled up 10 cm on the drainage trench wall on the side away from the house?
Thank you very much for the answers and greetings from Berlin
DIN 4095 for drainage specifies that especially for houses on clay soil, drainage is recommended. Therefore, I want to install such a system in addition, since the house will already be excavated. The drainage pipe is to lie on about 10 cm of gravel. In our clay, water hardly percolates.
With incoming water, 10 cm of water could constantly stand in the gravel bed at the strip foundation under the drainage pipe.
To counter this, I want to do the following:
The 0.5 m wide drainage trench has a 0.5% slope towards the corner of the house. A maintenance shaft is to be placed there. Furthermore, the drainage trench has about a 2% slope away from the house. Now I want to lay a strip of fleece in the drainage trench and on top of it a strip of pond liner (0.8 m wide, 0.5 mm thick) running continuously up to the maintenance shaft. This should be laid about 20-30 cm up along the basement wall and extend to the maintenance shaft. At this point, the maintenance shaft will have holes drilled into the pond liner and be wrapped in drainage fleece.
The aforementioned drainage mat on the basement wall should extend over the pond liner about 10 cm into the drainage trench bottom. Then drainage fleece is laid in the trench, and into this the gravel packing with the drainage pipe is placed.
Water arriving at the wall should thus be guided via the drainage mat onto the pond liner into the gravel bed and, if it does not find its way into the drainage pipe, flow on the pond liner from there to and into the maintenance shaft.
Question 1: What do you think of this solution?
Two further questions:
To still have as little water as possible standing on the pond liner, I want to additionally place the drainage pipe on a thinner gravel bed or even directly on the pond liner (or the drainage fleece) on the trench bottom. I would also like to lay the pipe at the side of the trench at the lowest point of the trench away from the house. Also conceivable would be to pull the pond liner up about 10 cm on the drainage trench wall on the side away from the house, so that a sort of trough made of pond liner (which is higher at the basement wall) would be created.
Three related questions:
Question 2: Drainage pipe on 3-5 cm of gravel or directly on the bottom?
Question 3: Drainage pipe on the side of the trench (maximum distance from the house, lowest point) or in the middle of the trench?
Question 4: Should the pond liner also be pulled up 10 cm on the drainage trench wall on the side away from the house?
Thank you very much for the answers and greetings from Berlin