Ladder in front of the window

I am working on better communication, I want to be clear and assertive but my tendency is to not say anything for a long time and then get passive aggressive or sarcastic. So here is a situation that I try to figure out how a clear and assertive communication would look like.

I live together with another person, a room mate so to speak. Over a week ago that person put up a ladder and went onto the roof. Then left the ladder there with the explanation that it was needed again the next day to go on the roof again. The next day the ladder was standing there but nobody went on the roof. I looked at that ladder for over a week, it’s right outside the kitchen window blocking my view of the back yard. After 5 days I made a comment to please go on the roof and do what was needed or move the ladder. Nothing happened other than the person got irritated with me and I stayed quiet. So this morning I collapsed the ladder and leaned it against the wall, leaving it where it was, for the person to go on the roof when ready. But for me, at least it’s not blocking my view anymore. But the other person got upset with me saying that if that ladder bothered me I could have put it away where it belongs, not just collaps it. (I know from experience of similar situations that if I had put the ladder away I would have heard how now this person has to go pull the ladder out again when it’s needed. Lose-lose)So I just stayed quiet and let the person vent, but I’d like to handle situations like this differently so I tried to do a model, can you please look at it

C – ladder in front of window blocking my view for over a week
T – Why is this person not doing what they said they will do or put the ladder away
F – frustration and irritation (what’s the difference between the two?)
A – lots of negative thoughts spinning in my head every time I look out the window, after about 5 days I asked to please put the ladder away, more negative thoughts spinning in my head, eventually after 8 days collapsing the ladder without saying anythig
R – The other person got annyoed saying I should have put the ladder away. I am not doing what I say I will do, having a clear and assertive communication

It seems like such a silly situation but I am trying to figure out how I could have handled this and similar situations better.