A lot of hvac systems use flex ducting and those are pretty easy to T off of since no sheet metal work is required.You will want to do some more research as the county may not consider your conversion a 4th bedroom unless permits have been pulled for electrical and/or mechanical.

The Treasure Valley is a very special place full of great people, and an awesome quality of life.  

Feel free to jump in the community here and also take advantage of the treasure of knowledge here.

I think you could build that if no utilities and just a box with a metal roof for like 10k maybe less.

There are some distribution centers there, corp HQ for a couple tool and metal manufacturers, some breweries, a mall, etc.

There's no guru that has a treasure trove of hundreds of below market value properties just waiting to pass on to his students.)Read these two thread before you spend any money on real estate guru seminars:Taking a stand after a $50,000 liePlease help $41,000 paid to a guru company to be refunded !

I started a metal fab/welding business with my family.

In the meantime we do not object if they buy a metal one at a big box.

Feel free to jump in the community here and also take advantage of the treasure of knowledge here.

Those tend to shrink slightly over many decades, causing the floors to slope.Often they've been replaced by temporary lally columns - the metal adjustable ones.