John Gill Commentary 1 Kings 9:10

"And it came to pass at the end of twenty years, wherein Solomon had built the two houses, the house of Jehovah and the king`s house" — 1 Kings 9:10 (ASV)

And it came to pass at the end of twenty years
From the time Solomon first began to build: when Solomon had built the two houses, the house of the Lord, and the king's house; the first was seven years in building, and the other thirteen; in all twenty.