I've done this type of work for brands like Bose, Delta Air Lines, RealtyMogul, Vail Resorts and others -- DM me if you want to talk more on the topic.

@Davidson Francois I ask about it being new because the first year the home exists the assessed value is based only on the land, not the improvements (the house). 

Are you buying something with potential to improve performance or something stabilized?

Are your priorities(in order) and your daily actions aligned and where can you improve?

An addition would most likely be considered an improvement, not a repair/maintenance, so you'd probably just add it to the property's cost basis. 

If I can buy it, fix the differed maintenance, improve the occupancy, and bring turnover back in line it will be a grand slam home run hit.  

Purchase price: $35,000 Cash invested: $25,000 2/1 on 3 lots = 0.35 acres in Lawn, Texas - population 353.Rehab budget $10,000Doing all cosmetic work myselfHouse pier & beam foundation leveledElectrical was already updatedplumbing was already updatedCentral air & Heat was also already presentTearing off porch currently to open up.

I find distressed properties with good bones, rehab them for top rents.My challenge is the valuation of the property is still performed as a small mf (1-4 units) so the neighborhood Comps dictate valuation more than my improvements or the rent rate.I started to wonder how valuation was done for a portfolio of properties.  

If you buy it with a low down payment and make improvements raising the value, you can then later get a mortgage for typically up to 80% of the new value of the home and pay off the existing loan.

I was looking into using your rental property as an air bnb instead.