I assume I need to inform the appraiser of the new dimensions before listing?

What are the dimensions you are considering? 

While we do prefer at least one king in a property, I wouldn't recommend it with those dimensions. 

@Jay Hinrichs it's same or smaller dimensions of a F-150 by design.

When you finish designing, you can use generic cabinets from Home Depot as long as they are the same dimension.

@Mindy Jensen can you share with us the dimensions of the header?  

It is not currently cash flowing due to the low down payment and the high interest rate, but bought it for appreciation, amortization and Tax savings. eventually it will cash flow and i will be able to benefit from that 4th dimension.

Also I had to make accurately drawn, scaled and fully dimensioned site plans and floor plans.

@Takisha Jones Obviously going to echo people saying you need to make sure you have the correct RM-1 zoning for the property, but more importantly you need to make sure the lot dimensions can support it.

But it's a pretty small garage (20 x 18.5 outside dimensions) and probably wouldn't support another level since it's got old cinder block walls.I thought about knocking it down and just build something bigger, but it kind of goes against my inclination to preserve and improve things that have already been built.