A depot—literally “in safekeeping”—refers to a separate account where part of your mortgage funds are held in reserve for specific purposes. In the case of a newly built home, the mortgage amount is placed in a construction deposit (bouwdepot), and the contractor is paid in instalments from this account as the work progresses.
For home renovations, a similar setup applies. The additional mortgage amount is placed in a renovation deposit (verbouwdepot), from which renovation costs are paid directly.