Hi @vanez,
Thank you for your post and welcome to the Bunnings Workshop community, it is fabulous to have you with us.
Did you have any photos from outside? This will help our members understand the problem better and make recommendations accordingly.
A lot of the problem can likely be solved by installing a drainage channel directly along the outside of the wall. For this to be most effective, it should be connected to your stormwater pipes by a plumber.
You will also need to look at sealing the bottom edge of the aluminium frame from the outside as this should not be allowing water to seep underneath it. This Selleys 300ml Grey 720 Exterior Silicone is likely a good option.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
