[basswipe]

As many here know I've taken time off from work and have been staying at my dad's house after his fall and surgery.

Well I've had some time on my hands and noticed a large sagging water stain in his down stairs laundry room.I just assumed that this had been addressed ages ago as my father never mentioned it again when first noticed years ago.This leak only seemed to manifest itself when there was combo of heavy rain with strong wind...like yesterday.

At about 9pm last night I hear my dad getting up to use the bathroom.Because of his condition I always go and ask if he needs anything.His upstairs bathroom is actually a full bath connected to a half bath.He uses the half bath because its connected to his bedroom and didn't get much use until a week ago when he came home.Anyway he gets done,I go back downstairs.About half hour later I go to use the toilet in the laundry and son of bitch there's water dripping from the ceiling.

I open up the ceiling to take a look and noticed the plywood around the main drainage pipe from upstairs is saturated.To make this long story longer, every time the toilet in the half bath is flushed the dripping starts.

I've flushed the toilet in the full bath,filled both sinks and taken a shower and no leaking.But if the toilet in the half bath is flushed and you then go use the sinks or flush the other toilet the dripping lasts longer and yet none of the other fixtures can initiate the leak on their own.

My major question is why would this leak appear to manifest itself more heavily when we get the heavy weather when the leak itself seems to have nothing to do with the weather?

Before the half bath was being used regularly the leak would show during heavy weather I assume in combo with some fixture in the full and/or half bath being used.But when there is no rain/wind the only way to intentionally make the leak is to flush the toilet in the half bath.Very confusing.

I'm a painter and not a plumber and have no idea what's going on here.I'm getting ready to pull my hair out.Stress I don't need.

Obviously I'll be calling a plumber 1st thing in the am Monday,but at the moment any insight here guys?

PS.Sorry about the novel sized post but it makes feel better just to get this out.