The front room, specifically towards the one side of the room, smells fishy usually after every time it rains. The smell is getting stronger now, so strong that it wafts down the hallway and it's taking much more of an ammonia smell now that it's stronger. It only lasts for <1 day and very rarely happens without rain. There don't seem to be any entry points to beneath the house for animals to enter. The strongest it's been smelt like very strong ammonia urine- its horrible! Please help. The house was rat infested about 4 years ago and had exterminators come around- I don't see any signs of rodents now.