Bathroom toilet smell & soil stack issues...

[Yohi124]

Recently bought a bungalow (70 years old-ish). Bad smells coming from around the toilet area periodically. Sometimes when it rains heavily, sometimes with no weather change. I have checked and flushed out the pipes going outside into the manhole, no problems there. So I thought the soil stack/vent pipe maybe?
At same time im re-doing the garden and had to dig out the cement around vent pipe and gutter down pipe to lay for paving. They are both cast. I have discovered both original clay bottom part were cracked and in bad condition. So need to replace/fix them, i tried flushing out the vent pipe with a garden hose and put in a bit of flexible stick to see if there was a blockage. That didnt help. Although I noticed that the vent pipe where it bends in the ground to go to meet the manhole/sewer, retains water, it still flows out and doesn't backup, but it sits in the bend about halfway full. Is this normal? Or does it signify a problem? Any ideas appreciated,

Thanks

 

[Hugh Jaleak]

Property of that age is likely to be on a 'Combined sewer' where the gutters will drain into the same system as the toilets etc, so can often happen in times of rainfall, the higher flow in the pipework can displace a build up of foul air in the sewer, but I would expect it to vent via the stack under normal circumstances.

Given what you've found so far of the system is in poor condition, it may be wise to get the drains CCTV surveyed, and a report done on their condition, if repairs are needed, better done before you lay new paving. Vent section should be dry, if any part of the system has standing water in it, then there is an issue that needs investigating.