I inherited a non-OOP C# web application where instead of using Master pages, they leveraged iframes for achieving similar (with a lot of trade offs). It is a n

I inherited a non-OOP C# web application where instead of using Master pages, they leveraged iframes for achieving similar (with a lot of trade offs). It is a nightmare, needs to be rewritten but no time available to do it. So in order to fix something, takes forever. In order to add something new, takes forever. I couldn't care less about respect considering I'm the only developer on it and I feel my manager and I have a good, respectful relationship as is. I just hate having to do fubar math to quote how long it will take to add/update something and having to put out a number I'd be embarrassed to quote on any other project.