What is the total square footage ?

__________________What is the approximate square footage?

Full replacement value might be close to $400K (its based on square footage and zip code), if you have a total loss the insurance company will rebuild the the house. 

You almost need to pop the roof on a 50's ranch for it to make sense and add sq footage.

Sometimes keeping it a SFR of the same square footage will result in a higher end value than a duplex.

This option was a bit less expensive than the attic, but we wanted to add the square footage and gain more value.

The partitioned area have been included in public records but causes a functional obsolescence, therefore adjustments were made.Due to above findings, this will hurt my ARV if appraisers will only use the lower square footage.

We buy detached single family homes, but you can definitely go with a town-home if that's what you'd prefer- you'd want to focus on large square footage, high bedroom count, and consider avoiding luxury features that add cost like rooftop decks unless they're important to you.Typically house hacks operate similar to a home office deduction - take your eligible, deductible expenses and multiply them by the portion of the house that is a rental (for example, if you buy a 4 bedroom town-home and live in one bedroom you could deduct approximately 75% of eligible expenses).

Luckily you had the sq footage to make it work.  

Background     - Location: Bay Area Peninsula     - House Price: ~$1M, Mortgage $700k     - Rent with similar square footage:  $4000/monthRunning the number, it looks like it marginally break-even.But I really wanted to have some cashflow during my holding years, so I am thinking to make an ADU.