Non engineer asking: where in geotech does it say i need perimeter drainage
Non engineer asking: where in geotech does it say i need perimeter drainage
(OP)
Hi,
I've searched and read and thought someone here could point me in right direction. From the geotech report, i do not see where it says i would need perimeter drainage. The guys say i dont need it, Water proof rep says water table is low enough so i dont need it. But, i would like to understand how to read this. I want to know where to look. Reason: grade is sloped and i have a basement condition.
I've searched and read and thought someone here could point me in right direction. From the geotech report, i do not see where it says i would need perimeter drainage. The guys say i dont need it, Water proof rep says water table is low enough so i dont need it. But, i would like to understand how to read this. I want to know where to look. Reason: grade is sloped and i have a basement condition.





RE: Non engineer asking: where in geotech does it say i need perimeter drainage
If you want to intercept surface drainage, it is easier to do so with a swale to direct the surface runoff from the sloped ground surface around your structure.
Assuming your water table is significantly below your basement foundation and slab, there is not much of a reason to put in subsurface drainage.
RE: Non engineer asking: where in geotech does it say i need perimeter drainage
RE: Non engineer asking: where in geotech does it say i need perimeter drainage
Mike Lambert
RE: Non engineer asking: where in geotech does it say i need perimeter drainage
RE: Non engineer asking: where in geotech does it say i need perimeter drainage
The state building law in Wisconsin requires it for every residential building, even 100 feet above a water table.
RE: Non engineer asking: where in geotech does it say i need perimeter drainage
RE: Non engineer asking: where in geotech does it say i need perimeter drainage
The holes in the PVC go at 4:00PM and 8:00PM, so they are on the bottom half of the pipe.
As cvg said it is easy and much, much cheapest to install it during construction when it is open.
The concept of clean washed rock by itself is ridiculous and there is no uniform definition of "gravel". I prefer to see a mixture of 3/4" clean rock and clean coarse sand to fill "choke) the voids between the rock and still carry the water to the PVC. I you just use 3/4" clean rock the water velocity is higher and it will fill up the the fines (clay, silt organics, etc.) from the surrounding soil. The percentage of sand depends on the coarseness of the sand.
Ideally if you really want the best, lay filter fabric against the wall, several inches under the PVC and then against the natural soils. Fill between the PVC and fabric with the sand/rock mixture.
A perforated drain system is a long term method to reduce the amount of water and pressure on the walls and slab. High flow rates are not necessary since most water runs off away from the home and hopefully the downspouts are not connected the perforated pipe.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Non engineer asking: where in geotech does it say i need perimeter drainage
RE: Non engineer asking: where in geotech does it say i need perimeter drainage
RE: Non engineer asking: where in geotech does it say i need perimeter drainage
I have a friend that built over 3000 homes and routinely installed both interior and exterior linked drains in every home (standard detail) because the cost was so low in comparison to future problems. - Standard details, materials and procedures. - No wet basements in the 3000 homes.
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Non engineer asking: where in geotech does it say i need perimeter drainage