Room Addition to my SFH

[Dallas Pauu]

Aloha,

I've been wanting to dive into REI for some time now and I've just sold my first property a few months ago for some capital to purchase a SFH on Oahu. I bought a small SFH 2bdrm 1bath at a little over 700sqft of living space. The property itself is about 6,600 square feet which qualifies for an ADU and I plan on building one the future prior to moving out and turning this property into a rental. I've been looking for estimates online on what it would cost to add a room the house to increase the square footage and add value in the process and I've been seeing prices per square footage is between $200-$400. I'm just looking for someone in Hawaii that has done a home addition and could give me an idea of what I'm looking and investing into this property and if these numbers are correct. I plan on building a 12x12 primary with a primary bath. I plan on doing all the work after the electrical and plumbing is installed as well.

Also here in Hawaii while I was house hunting I noticed that many of the houses have unpermitted builds and they are still selling as if buyers don't care. I plan on doing a permitted build which I know will take longer. Do you think it will be a better selling point this way and add more value than an unpermitted build?

Thank you BP community any advice will be appreciated

-Dallas