VAT on rebuilt outhouse/barn - insurance claim

Situation - husband and wife own house and grounds.  They are directors and shareholders of their own building company who use part of an outhouse for an office (the other part is used for personal use).

During the heavy snow last winter, the roof and some of the walls collapsed due to the weight of the ice, and it has been deemed easier (and likely safer) to completely rebuild the outhouse.  The insurance company have paid the husband and wife direct - and their company is the one doing the work in rebuilding the outhouse.

My question is - should VAT be charged on this work, or is there some zero rated/lower rated element they could use?  There are no option to taxes involved or anything like that.

Thanks in anticipation.