Adding Extra Bedroom into Home

[Danny Mak]

I made my own analysis model for rental properties and I am trying to purchase in Lowell, MA.

I am realizing how difficult it will be to cash flow with my small down payment on a home. So I want to get creative with the home. I want to purchase a 3 bedroom place with 6 or 7 rooms and turn one of the rooms into a bedroom, turning the home to a 4 bedroom.

Does anyone have any experience with building an extra room in the home like this?

Can you share your opinion about what to look out for and/or if this is a good/bad idea in general?

Thanks!