ᐅ Solid single-family house with a full basement – installing basement drainage as a DIY project
Created on: 14 Apr 2016 19:57
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Baumhaus.BauB
Baumhaus.Bau14 Apr 2016 19:57Hello everyone,
We are building a solid single-family house with a fully basement and are installing a drainage system ourselves. This is not mandatory, but we want to be on the safe side.
We will probably install "Fränkische" DN100 (4 inch) perforated pipe around the house, with an inspection chamber at each corner and a pump connected to the infiltration system in one of them. I have been thinking about the setup as follows:
We will lay a layer of gravel, then the pipe, followed by backfilling with gravel (how high should this be? Is about 30cm (12 inches) above the pipe enough?), then a geotextile fabric on top. The basement wall insulation will also get a geotextile fabric (as recommended by Fränkische). Then we will backfill up to the top edge with topsoil.
My questions are:
What type of gravel should be used? A landscape gardener I know suggested 8/32 or 16/32. Fränkische recommends 8/16.
Are there better geotextile fabrics available, or should a dimpled membrane be installed on the basement wall to help water flow down more effectively?
Should geotextile fabric also be placed around the pipes?
At what depth should the DN100 (4 inch) pipe be installed? Should it possibly be placed below the floor slab level?
Do you have any other tips?
Thanks in advance
We are building a solid single-family house with a fully basement and are installing a drainage system ourselves. This is not mandatory, but we want to be on the safe side.
We will probably install "Fränkische" DN100 (4 inch) perforated pipe around the house, with an inspection chamber at each corner and a pump connected to the infiltration system in one of them. I have been thinking about the setup as follows:
We will lay a layer of gravel, then the pipe, followed by backfilling with gravel (how high should this be? Is about 30cm (12 inches) above the pipe enough?), then a geotextile fabric on top. The basement wall insulation will also get a geotextile fabric (as recommended by Fränkische). Then we will backfill up to the top edge with topsoil.
My questions are:
What type of gravel should be used? A landscape gardener I know suggested 8/32 or 16/32. Fränkische recommends 8/16.
Are there better geotextile fabrics available, or should a dimpled membrane be installed on the basement wall to help water flow down more effectively?
Should geotextile fabric also be placed around the pipes?
At what depth should the DN100 (4 inch) pipe be installed? Should it possibly be placed below the floor slab level?
Do you have any other tips?
Thanks in advance
U
Ulrich Fuckert15 Apr 2016 12:06The DIN 4095 standard specifies the following requirements:
The thickness of the gravel packing (drainage layer) surrounding the drainage pipes depends on the grading curve of the filter layer or drainage layer.
For a grading curve of 0/8 mm, 0/32 mm (mixed filter according to DIN 4095 section 2.11), or 4/16 mm (drainage layer), a minimum thickness of 15 cm (6 inches) must be maintained.
For a grading curve of 0/4 mm or 4/16 mm (both drainage layers), 10 cm (4 inches) is sufficient according to Table 6 of DIN 4095.
Whether a geotextile fabric must be installed around the gravel packing of the drainage pipes depends on the underlying soil, the backfill material of the excavation, and the grading curve used to surround the drainage pipe.
Encasing the drainage pipes with at least 20 cm (8 inches) of gravel sand of the grading curve (0/32 mm / 0/8 mm = mixed filter) can eliminate the need for encasing the drainage/filter layer if, additionally, the excavation above the drainage is backfilled with the same filter material.
Here is a small illustration from DIN 4095:
The pipe must be laid so that its invert at the highest point is at least 20 cm (8 inches) below the top edge of the slab. From there, the drainage pipe is installed with a 0.5% slope.
The thickness of the gravel packing (drainage layer) surrounding the drainage pipes depends on the grading curve of the filter layer or drainage layer.
For a grading curve of 0/8 mm, 0/32 mm (mixed filter according to DIN 4095 section 2.11), or 4/16 mm (drainage layer), a minimum thickness of 15 cm (6 inches) must be maintained.
For a grading curve of 0/4 mm or 4/16 mm (both drainage layers), 10 cm (4 inches) is sufficient according to Table 6 of DIN 4095.
Whether a geotextile fabric must be installed around the gravel packing of the drainage pipes depends on the underlying soil, the backfill material of the excavation, and the grading curve used to surround the drainage pipe.
Encasing the drainage pipes with at least 20 cm (8 inches) of gravel sand of the grading curve (0/32 mm / 0/8 mm = mixed filter) can eliminate the need for encasing the drainage/filter layer if, additionally, the excavation above the drainage is backfilled with the same filter material.
Here is a small illustration from DIN 4095:
The pipe must be laid so that its invert at the highest point is at least 20 cm (8 inches) below the top edge of the slab. From there, the drainage pipe is installed with a 0.5% slope.
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