Would appreciate some help.

[Eror404]

Thank you for you're replies.

It is a plastic drain cover. I have no clue if the mastic is air tight. I have no clue if the mastic if doing a good enough job. All i can do is hope it was applied properly.
I dont particularly know if the mastic will prevent air or any thing from arising. All i know is sewage from my neighbours bog flows under my dinner table.
But if you guys think its ok, then i guess its ok 🙂

 

[chris watkins]

I will repete, if you are unsure ask your local sewage undertaker (normally the same as water) to confirm all is OK.

 

[Darren Jackson]

You accidentally mentioned 'Environmental Health' instead of building control, But maybe it is time to get Environmental Health to have their say. That cover is not approved for internal use and is not secured down or have an approved airtight seal. As for neighbouring waste flowing through your chamber, that is perfectly normal and nothing wrong with that. It is a shared sewer system.

 

[Ric2013]

You could ask if the drain has been pressure tested to prove that the mastic is sealing. It isn't a difficult or a long process, but it would prove the drain was airtight. Although a few pints of hot water down the sink would send up a nasty smell if it isn't airtight, so if you can't smell the drain, it probably is airtight.