I have just installed a new kitchen which is located directly beneath the family bathroom. Every time I use either the family bathroom or the en-suite (which is located next door to the family bathroom) there is a sewage smell downstairs in the kitchen, and only the kitchen, which lasts for approximately a few hours and then all is normal afterwards. Prior to fitting the new kitchen, this never occurred before.
My original assumption was to check all the u-bends to see that they had water in them, which they did. I have already put bleach and costic soda down the bath, toilet and sink in the bathrooms but to no effect. I originally assummed that there may be a blockage in the pipes but the water is flowing normally when i check the outside manholes.
Clearly there is something amiss with your drainage system as a result of the kitchen fit. It's most unlikely to be conincidental.
The obvious advice from where I'm sitting (as I can't see the problem) is check all your joints and traps. However, as you seem to have done that already then you need to get someone in to look at it if you can't find it yourself.
Hi. We have the same problem with kitchen sink smells since replacing the kitchen units and having the waste drainage fitted with "u" bends instead of as before a waste trap, our plumber advised this was how it was now done. bleach/disinfectant covers for a while but it does return again. still looking for a cure
THIS "MAY" BE A SITUATION WHERE A VACUM IS SET UP IN THE KITCHEN DRAINAGE PIPES WHEN THE BATHROOM DRAINAGE IS USED CAUSING THE "U"BEND WATER TO BE SUCKED OUT OF THE KITCHEN DRAINAGE TO LEAVE OPEN PIPEWORK WHERE SMELLS LEECH BACK FROM SOIL PIPE UNTIL THE "U" IS PRIMED AGAIN.
AS HAS ALREADY BEEN SUGGESTED, REMOTELY DIAGNOSING FAULT IS DIFFICULT BUT A DECENT PLUMBER SHOULD BE ABLE TO CONFIRM AND REMEDY IF YOU ARE UNABLE TO DIY IT.