Hi Larysa,
If the company buys and sells houses then this will be an exempt supply for VAT purposes.
This will mean that the company will not be required or be able to register for VAT as the company will not be making taxable supplies.
If the properties have been empty for more than 10 years before the work starts or if the company is converting non residential property to residential property then the subsequent sales wil be taxable supplies ans so then there would be a requirement for VAT registration.
Please see the guidance below:
3. The liability of a supply of land
5. Zero rating the sale of, or long lease in, non-residential buildings converted to residential use
Thank you.