Flooded out
New Member
Big issues here. 10 story condo constructed in 1924, renovated in 1984 and again ad hoc 1999 - present. We have a two story unit on the first floor meaning that half the unit is below grade. The city sewer and storm run off use the same system. There were two units per floor when built in 1924. This was expanded to 6 units per floor on 2nd through 9 and 8 per floor on 1st and 10th. There are four plumbing stacks all of which come down to 8" below the bottom floor which is below grade. These all make their way quite directly when leaving the building to a brick 24" standpipe in the courtyard that is shared by the sewer and storm systems. It is somewhere between 80 and 100 feet deep.
The number of toilets, sinks, washing machines, etc. on each stack has double since it was built. No modifications to the 4" pipes leading from each stack to the standpipe have been made as of '99.
In '99 we had a severe flood presumably caused by excess storm run off. Our downstairs below grade toilet is apparently the lowest point. It was blown off it's bolts, sent into the air followed by water and some sewage until over a 10 minute period 5' of the stuff filled our downstairs 800 sq ft.
The developer who sold the units in '99 said "oh well, city problem". To protect our unit we placed a check valve as close to where the main drain leaves our unit as possible. This prevented major floods.
Since then we've had three ongoing issues that may or may not be related.
1. Our downstair toilet gurgles regularly and becomes slow, then fills with soap suds at all hours and on all types of occasions, heavy use times, light use times etc.
2. On occasions where the storm water backs up to our check valve the predictable happens and we get flooded from the 9 floors above pn the same stack, using their plumbing.
3. When there is heavy rain but no flooding, the check valve can be heard loudly opening and slamming shut and the toilet violently gurgling and splashing but not overflowing.
I have had a plumber run a camera down the main line from the stack looking back to where it joins the riser and out to the standpipe. He found nothing. He said he felt the issue was that it should be a six inch pipe. Obviously digging up three units (it runs under our floor and then the wall between two other units on its way out), the driveway in front of the building and standpipe to replace the line would be expensive and inconvenient.
The only solution I seem to be left with is to put a check valve between my downstairs toilet and the main drain line from the stack. As three other units join this line at some point I've warned the Condo Association that this solution will result in more problems for the other unit on the line while curing mine. I have also advised them that it would be prudent to place a check valve on the main drain line for this problem stack (it is closest to the standpipe) outside of the building between it and the standpipe. (in which case I'll remove my check valve from the main line for the stack and just have the one between my downstairs toilet and the main line.)
My questions are: Am I missing something here, solution wise? Could venting be part of the problem? (during the renovations since '99 there has contractors have poured debris down drain line and vent lines without redress). Do you have any other suggestions for me?
Apologies for the length.
The number of toilets, sinks, washing machines, etc. on each stack has double since it was built. No modifications to the 4" pipes leading from each stack to the standpipe have been made as of '99.
In '99 we had a severe flood presumably caused by excess storm run off. Our downstairs below grade toilet is apparently the lowest point. It was blown off it's bolts, sent into the air followed by water and some sewage until over a 10 minute period 5' of the stuff filled our downstairs 800 sq ft.
The developer who sold the units in '99 said "oh well, city problem". To protect our unit we placed a check valve as close to where the main drain leaves our unit as possible. This prevented major floods.
Since then we've had three ongoing issues that may or may not be related.
1. Our downstair toilet gurgles regularly and becomes slow, then fills with soap suds at all hours and on all types of occasions, heavy use times, light use times etc.
2. On occasions where the storm water backs up to our check valve the predictable happens and we get flooded from the 9 floors above pn the same stack, using their plumbing.
3. When there is heavy rain but no flooding, the check valve can be heard loudly opening and slamming shut and the toilet violently gurgling and splashing but not overflowing.
I have had a plumber run a camera down the main line from the stack looking back to where it joins the riser and out to the standpipe. He found nothing. He said he felt the issue was that it should be a six inch pipe. Obviously digging up three units (it runs under our floor and then the wall between two other units on its way out), the driveway in front of the building and standpipe to replace the line would be expensive and inconvenient.
The only solution I seem to be left with is to put a check valve between my downstairs toilet and the main drain line from the stack. As three other units join this line at some point I've warned the Condo Association that this solution will result in more problems for the other unit on the line while curing mine. I have also advised them that it would be prudent to place a check valve on the main drain line for this problem stack (it is closest to the standpipe) outside of the building between it and the standpipe. (in which case I'll remove my check valve from the main line for the stack and just have the one between my downstairs toilet and the main line.)
My questions are: Am I missing something here, solution wise? Could venting be part of the problem? (during the renovations since '99 there has contractors have poured debris down drain line and vent lines without redress). Do you have any other suggestions for me?
Apologies for the length.
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