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.
Is anyone able to help please.