Completion certificate (NI only)
Your local building control officer will do a final inspection to issue your Building Regulation Completion Certificate. The Completion Certificate and the plan Approval Certificate are legal documents. You should keep these with your property’s deeds (it may be difficult to sell your house without these documents). The certificate states that the building satisfies building regulation requirements.
Once the house is built, you can apply to get the VAT back on all building work through the DIY VAT Refund Scheme. You will need all of your receipts for this. The refund is available to new builds but also for a house that has been unoccupied or unused for ten years or more, or for a conversion project.
Note that you can only claim your VAT back once the house is considered complete, which is unfortunately open to interpretation, and it can only be applied for within three months of that date. Details of how the HMRC deems a house to be complete is available through the VCONST02530 guidance document on their website.
Building control’s completion certificate should suffice but if the house was habitable before this, e.g. with fully functioning kitchen and bathroom, functioning heating system, etc., you may run in trouble with the three month rule as the HMRC may deem that it was complete when those aspects were finished.