Serving Section 21 with out-standing maintenance issues

Can I serve a Section 21 while the tenant can’t reside in the house because of rebuilding work?F

Can you advise me on my situation? I made a mutual agreement with my AST tenant to vacate my house temporarily for 3-4 months during rebuilding in lieu of rent, and he agreed. But while he was away, I was given serious information about him that led me to give him two...