I've alread put a sink unblocker product down overnight but hasn't fixed it.

Daisynook, June 2004

It sounds to me as though you have got a syphoning problem with your sink, the trap is being emptied by another sink or bath discharging down the system, remove the trap, take it to a builders merchant, do the girly act and tell them you need an anti syphon trap, when you refit it remember to use fairy liquid around all the rubber bits on the connections and do not do it up too tight as it will distort the seals and make it leak.

Derek, June 2004

if you have water in the traps to the sink and loo you should not be smelling anything. it is for exactly this reason that they are there. try emptying the traps completely and refilling them

kev, June 2004