The $10k extra the dining room costs when you buy it in 2025 is worth $15k when you sell in 2035. You'll have paid $400 a year in interest, but you'll have made that in appreciation alone.

$10k would get you about $500 a year long term (5%).

$500 a year doesn't go far, and that assumes you don't use the dining room for any other purpose than a couple of parties a year.