My girlfriend is going to renovate her house (which is more than 10 years old). The building/environmental permit is okay and the plans from the architect are finalised. She wants to purchase the materials at 6% vAT. As a self-employed person in secondary occupation in construction, can I make these purchases and invoice her for them? I have read some information on the website (dexxter.be/een-rennovatie-aan-6-btw/), but this has not clarified the matter here for me.