I cannot use visual composer plugin in some pages

Hi,
I wanna use visual composer in all pages (default templates, such as all projects page, or single project page) and edit the templates like adding some new blocks to existings…
You may think that I can build a new page and assign the link, but some default blocks are not provided in the composer… I think the best way to resolve this problem is to add some blocks to the default templates that we can edit them is visual composer.
(another idea is to add some sub-element to visual composer provided for this them)
Please help me to solve this problem