Bad smell in bathroom

[stevewood]

A friend recently had a new bathroom suite installed (not by me!).

Since then he has an intermittent bad drain smell in the bathroom, more noticeably in the mornings .

To help him out, I fitted anti-syphon traps to the bath & the basin to see if this would help... but it hasn't.

Has anyone had the same problem? Does anyone have any suggestions as to what it could be?

 

[Bahco]

Sounds like you have incorrectly fitted gradient on waste pipes which is losing trap seal.
Place a straw in your traps and then place your finger over it. Withdraw and see if any water is in the straw. This will tell you the depth of your trap seal.
Obviously no water = no trap seal.
Smells can only enter via the traps so investigate properly.

 

[ChrisR]

Check the stack pipe(outside) for birds' nests. If the ventilation is blocked, a pressure in the sewer can force air up past a trap. There should be a "balloon" grating thing on top. If not, you have to get up there.