Sewers - sewer gas smell in first flooor bathroom?

sewer gas smell in first flooor bathroom?

Also, this toilet and sink were put in . Found that no vent stack was on pipe. Put a spring loaded valve on it in the wall.Smell still there.

Go up on roof, check lenghth(height) of stanpipe, and extend 6"-18" if needed. Also, check to see if any blockages in pipe.
Do you have a septic tank? Might need to get it pumped out. If you have city sewer service, you might want to give them a call and explain the situation. If you live in an apartment give the management a call and explain the situation.
Also make sure there is anough water in the toilet bowl to block the smell from coming up through the trap, or a leak in the collar that the toilet sits on to act as a gasket, also sealing out smells. It's possible the smell is coming from the cellar.
If you have a floor drain, the trap could be blocked, preventing the smell from going up the exhaust pipe.
No there isnt. I havent noticed anything since I've been here, but thanks for asking.
It sounds like your water system is backed up! we use to have that problem every spring in our old home- and wow did it STINK! every spring when we got rain and the snow melted it would back up and man just running the water in the sink gagged you!!!! Call a sewer specialist and he'll fix it right up for you! Good Luck