Shacking up, settling down and ... planting seeds??? Justin Bieber and Hailey Baldwin are house hunting for their first marital home and we've got the EXCLUSIVE pix and info!

X17online can report exclusively that Mr. and Mrs. Bieber checked out an ENORMOUS house in Encino, on Tuesday, on the market for a cool $13 million! It's a dream home, for sure -- perfect for back yard barbecues and ... raising a family!

The 12,500-square-foot mega-manstion features ten bedrooms, 11 bathrooms and is complete with a movie theater, pool house, basketball court and even TWO garages for all their sweet whips.

Justin and Hailey spent about 45 minutes touring the estate and were all smiles when they left. And just to ask -- hey, you never know, maybe Jailey were in the mood to break some big news! -- we asked Baldwin if she has a baby on board. Watch!

That's not the only home the couple's considering, though it's clearly the nicest (and most expensive!). Hailey checked out a much smaller, must more modest home last Friday, near Kim and Kanye's old pad in Bel Air. That home is still under construction and will likely finish at closer to 6,000 square feet and be priced around $5 million. A far cry from the $13 million estate they looked at yesterday! We say, bigger is better!