Currently working on a big catalogue where I have several documents, I have also single page and double page spread documents inside one book. Is there an option to make the whole book double page (combining single and double pages) without adding useless new pages between to make the single page be double for example? I would like to keep the documents seperated (editable each if I need to add more pages to one big section). Book needs to be smooth double paged without single page break.
I think I understand waht you are asking -- You have a book file that contains a number of documents -- some of them have only one page, and some have multiple pages. If that is the case, setting all of your documents as Facing Pages and updating the page numbering from the book panel should number and position all of your pages correctly for the final book.
If this is not what you meant, please provide more detail on the issue.
Can you upload a copy of your InDesign document here? Delete page content if you prefer, but it needs to be a copy of the exact document you are having trouble with.
A couple of thoughts I have without examining the document --
1) Look at the eight pages that make up the spreads 4 and 5 in your PDF. It is acting as if each of the 4 two-page spreads is actually set as a single page.
2) After you have checked item 1, don't export as spreads - this messes up page numbering and in the PDF, and makes viewing more difficult. Instead, export as single pages, but set your PDF viewing options in the PDF Export menu to either 2-up or 2-up - cover page. It will still view as spreads in the PDF, while maintaining its page count.