Hi all, grateful for your expertise on the following. DIYer, not pro.
Rural property in France
Single storey. Septic tank. Late 80s construction with concrete slab subfloor. All of the waste pipes run in the concrete, and exit the property at the chamber as pictured, just outside the building. The longest run is approximately 8m, with a drop of maybe 80cm. The chamber then drains with one pipe to the septic tank, approx 10m.
The two main waste pipes are 100mm diameter (4in), exit in parallel as pictured. My diagram hopefully demonstrates the right one (as seen from the chamber) drains the toilet only and is vented via the stack to the right, as pictured. This vents externally through the loft and roof. The left one drains the bathroom sink, bidet, and also an existing shower (now removed). Despite only collecting 40mm waste from sink/bidet/shower, it is 100mm diam at its full length. As far as I can tell, it is not vented at any part. Additionally there doesn't seem to be any traps at each fixture.
My plan is to install a new toilet and a new shower as pictured, and tie it into the left 100mm waste pipe - green pipework is planned.
In my head, having a large open inspection chamber at almost the same height as the collecting system, means that gases (from the tank) aren't particularly likely to be entrained to the pipework. Additionally, the single storey nature means that it is less likely to have siphons pulled. Might be completely wrong on this.
My questions are:
Rural property in France
Single storey. Septic tank. Late 80s construction with concrete slab subfloor. All of the waste pipes run in the concrete, and exit the property at the chamber as pictured, just outside the building. The longest run is approximately 8m, with a drop of maybe 80cm. The chamber then drains with one pipe to the septic tank, approx 10m.
The two main waste pipes are 100mm diameter (4in), exit in parallel as pictured. My diagram hopefully demonstrates the right one (as seen from the chamber) drains the toilet only and is vented via the stack to the right, as pictured. This vents externally through the loft and roof. The left one drains the bathroom sink, bidet, and also an existing shower (now removed). Despite only collecting 40mm waste from sink/bidet/shower, it is 100mm diam at its full length. As far as I can tell, it is not vented at any part. Additionally there doesn't seem to be any traps at each fixture.
My plan is to install a new toilet and a new shower as pictured, and tie it into the left 100mm waste pipe - green pipework is planned.
In my head, having a large open inspection chamber at almost the same height as the collecting system, means that gases (from the tank) aren't particularly likely to be entrained to the pipework. Additionally, the single storey nature means that it is less likely to have siphons pulled. Might be completely wrong on this.
My questions are:
- Is it best to connect the left 100mm waste to the existing vent stack?
- Assuming there are traps present on all fixtures, would an air admittance valve be a suitable alternative?
- Is there anything else you strongly advise?
