John Gill Commentary 2 Chronicles 8:12

"Then Solomon offered burnt-offerings unto Jehovah on the altar of Jehovah, which he had built before the porch," — 2 Chronicles 8:12 (ASV)

Then Solomon offered burnt offerings to the Lord
Meaning not barely at the time he rebuilt the above cities, for it was his constant practice:

on the altar of the Lord, which he had built before the porch ;
the brasen altar, which was at the entrance into the temple, within the court; of which see (2 Chronicles 4:1) .