Inhousekai theme is supported Portfolio Post Type. This post have 3 different single template that you can set in the Options > Content Option > Single Portfolio Options.
This post type have "Portfolio Use Page Builder" template that's mean your single portfolio posts will turn into page builder template. Allow you to build it with page builder and it blocks.
and there are 3 types of post formats that you can choose: Standard, gallery and Video.
Portfolio Detail Options.
Portfolio Style 1 Result
Portfolio Style 2 Result
Portfolio Style 3 using Page Builder Result.
In this single type, your sidebar will turn into fixed (sticky) sidebar. But please note: This feature will not work if you use fixed footer.