Originally Posted by joypulv
Try to explain it better here and try to say where you smell it most, what room or rooms.
Usually a plumber can locate dead animals. That's the first guess. But they can be in walls and ceilings and chimneys and crawl spaces. Try an exterminator, but you may not get one to look for free.
Thank you split level house with the smell in the upper staircase and hall does not smell like something dead though but it leaves a bad taste in mouth and visitors have said the same