Zone file permissions issue (Debian)

[zenntrix]

Operating System: Ubuntu 18.04

When the zone files are created, they have the following permissions

-rw-rw---- 1 root bind 448 Mar 13 13:33 0.15.172.in-addr.arpa
-rw-rw---- 1 root bind 464 Mar 13 13:33 example.com

The service which is started as user bind9 isn't able to access the files, the service reports

zone 0.15.172.in-addr.arpa/IN: loading from master file /var/local/named-zones/0.15.172.in-addr.arpa failed: permission denied
zone example.com/IN: loading from master file /var/local/named-zones/example.com failed: permission denied

If i set the file owner to bind and then restart the bind9 service the problem goes away

[zenntrix]

Have resolved this by moving away from bind_zone_dir: /var/local/named-zones