The $50k is an estimate on catching up on deferred maintenance.

so as long as you live in the home for 2 years in years 16-20, you will qualify.if you own and live in the home for just 2 years and sell after 2 years you qualify.also, 1031 like kind exchange allows you to defer capital gains not exclude it.

Sometimes the seller wants to defer capital gains and keep cash flow.  

Buy another property, rent it, and take the depreciation -stay focused on your portfolio. look to use tax free or tax deferred IRAs or 401ks to reduce taxable income. 

Your second question is not exactly my expertise as I don't do construction loans, so I would defer to somebody else on that one.

Is there any deferred maintenance?

Hi Dong,Since you mentioned "profit"  and  you further brought up that depreciation is super high since you were renting it.I will assume the original purchase price was $380,000 and you were depreciating it the past 7 years and now your taxable gain is $116,727 calculated as follows.400,000 - 380,000 - 96,727(depreciation at 7 years assumed brought on jan 1 and residential building) = 116,727.Your agent is referring to section 1231 of the Internal revenue Code where the IRS allows you to DEFER gain on an investment property if you sell and acquire an investment property.The code calls for very strict rules on when you need to choose your new property once your property is sold.

This helps me determine my immediate Rehab needs and what can be deferred for my CapEx reserves requirement.

You are buying a property that has been substantially upgraded to at or near retail levels and you are buying a property with no underlying deferred maintenance.  

Granny homes - grandpa died 20 years ago, and most maintenance has been deferred since.