Bocatoo
2021-07-14 12:45:28
- #1
Hello community,
Thanks for unlocking.
A question about a complex topic - infiltration on a property under a newly to be built house.
We own a property (NRW infiltration obligation) with an existing house which infiltrates over a "still" free garden/lawn area.
A part of the property is to be separated (official survey, land register etc.) and a bungalow is to be built on it.
The building envelope lies (since it is not possible otherwise due to size) over the old infiltration system of the existing house. The system was built and installed there around 1975, exact plans and depths are not available, can only be estimated. (branched pipe system, probably clay pipes)
Whether this system still infiltrates at all is unclear, according to the hydrologist it is rather unlikely, since the supply line from the existing house possibly also has root ingrowth/blockages, as evidenced by rainwater running off uncontrollably on the property.
(There is no rainwater sewer or combined sewer - only wastewater!)
Since our property, as well as the neighboring properties, have a slight slope, water runs downhill onto a municipally managed roadside strip and infiltrates there or runs off over the street (at least during heavy rain). This circumstance is known everywhere, likewise to the municipality, who just does not want any "disturbance."
We have 2 hydrological expert reports certifying that we have soil (planned building plot) that is hardly suitable for infiltration, with great difficulty a drilling point was chosen for a pipe trench (for new building), further locations are not available.
Space-wise it is already difficult as this planned pipe trench was calculated to be very deep (4m depth and 10m length), plus setback distances to neighbors, setback distances to an existing shed, setback distances to a gas earth tank, setback distances to the newly to be built bungalow.
That means a 2nd pipe trench (possibly replacement for the existing one under the planned house) finds a) no space b) no infiltration-capable soil for the large roof area of 270 m2 of the existing house.
On-site appointments with the regional building authority have already taken place, result, they also don't know ...???
(Investigations, values etc. are available)
That is the fact at the moment.
To my questions:
1) We basically would have no problem building on the property on the "old" infiltration system, structurally certainly feasible (slab, strip foundations, waterproofing, embankments, water technical isolations etc.) I do not find any requirements whether this is allowed, would be allowed or similar.
Mostly I hear - whatever, we don't know either, don't wake sleeping dogs ... main thing is quiet
I have an appointment next week with the lower water authority and again hydrologist.
How do you see the matter? Does anyone have experience with it? ..similar problems?..how solved?
Anything helps, I can give more info, did not want to confuse here with soil values.
Thank you all,
Rolf
Thanks for unlocking.
A question about a complex topic - infiltration on a property under a newly to be built house.
We own a property (NRW infiltration obligation) with an existing house which infiltrates over a "still" free garden/lawn area.
A part of the property is to be separated (official survey, land register etc.) and a bungalow is to be built on it.
The building envelope lies (since it is not possible otherwise due to size) over the old infiltration system of the existing house. The system was built and installed there around 1975, exact plans and depths are not available, can only be estimated. (branched pipe system, probably clay pipes)
Whether this system still infiltrates at all is unclear, according to the hydrologist it is rather unlikely, since the supply line from the existing house possibly also has root ingrowth/blockages, as evidenced by rainwater running off uncontrollably on the property.
(There is no rainwater sewer or combined sewer - only wastewater!)
Since our property, as well as the neighboring properties, have a slight slope, water runs downhill onto a municipally managed roadside strip and infiltrates there or runs off over the street (at least during heavy rain). This circumstance is known everywhere, likewise to the municipality, who just does not want any "disturbance."
We have 2 hydrological expert reports certifying that we have soil (planned building plot) that is hardly suitable for infiltration, with great difficulty a drilling point was chosen for a pipe trench (for new building), further locations are not available.
Space-wise it is already difficult as this planned pipe trench was calculated to be very deep (4m depth and 10m length), plus setback distances to neighbors, setback distances to an existing shed, setback distances to a gas earth tank, setback distances to the newly to be built bungalow.
That means a 2nd pipe trench (possibly replacement for the existing one under the planned house) finds a) no space b) no infiltration-capable soil for the large roof area of 270 m2 of the existing house.
On-site appointments with the regional building authority have already taken place, result, they also don't know ...???
(Investigations, values etc. are available)
That is the fact at the moment.
To my questions:
1) We basically would have no problem building on the property on the "old" infiltration system, structurally certainly feasible (slab, strip foundations, waterproofing, embankments, water technical isolations etc.) I do not find any requirements whether this is allowed, would be allowed or similar.
Mostly I hear - whatever, we don't know either, don't wake sleeping dogs ... main thing is quiet
I have an appointment next week with the lower water authority and again hydrologist.
How do you see the matter? Does anyone have experience with it? ..similar problems?..how solved?
Anything helps, I can give more info, did not want to confuse here with soil values.
Thank you all,
Rolf