Evening all, I have a leaking flat roof roughly 3x3m. Looks like osb/plywood has sagged in couple of spots, more than likely Joists are not in ideal condition. Thing is I don’t want to spend money on a roof I plan on knocking down. I plan on building a large extension so need to a cheap temporary fix. would I be able to pva dipped areas and then pour a fibrous liquid floor screed over this. Maybe if required paint over acrypol type product Or corrugated plastic sheets an option. I need roof to last another 5 years but I need all the money for large extension. Builder wanted to charge 2/3k. To much when I plan to knock down this part of the house. suggestions welcome.