Full disclosure: I'm no professional, just giving some insight as to what our inspector discussed with us.It actually was beneficial in that the inspector could easily go under and inspect the structure, subfloor, plumbing, etc..The concerns that our inspector listed were things such as damage/rot to sub-floor,  ensure the support post/columns are structurally sound, the raised front patio is concrete and brick, but they used temporary wooden bracing in the construction but left them in place afterwards which he said provides termites a way to get to the framing of the house.

I have several patio homes in Houston with room to add more. 

I also retrofitted the bottom drainage as the original was just cheap plastic & began to leak.

There are some cheap components on some like plastic sinks and faucets, Uber cheap cabinets and odd shaped doors.

Bandit signs - these are the 18" x 24" plastic signs you see on the side of the road.

don't let these people discourage you, build new and have a maintenance trouble free house/rental for 30+ years.. or more.for just a little bit more cost (sometimes a way less cost, depending where you are building it).. and as long as it is built right.also you can design it exactly as you want.porch/patios, garage, where the bedrooms are/ windows views are/ kitchen etc..I can't tell you how many houses I have looked at that make ZERO sense. bedrooms off other bedrooms,  1 full bathroom off a living room downstairs with no baths up stairs where bedrooms are, or the 1 bathroom is off a bedroom only, houses with a great view out the back and only 1 window in the bathroom capitalizes on it.. or the house is facing the wrong way for best view optimization,  like the amount of bad decisions is amazing.I've probably looked at close to 250 houses in person in the past 6 years (thousands not looked at in person). something wrong with every single one. or they just need too much work for the asking price.build new.

Some areas rental rates are generally determined by the square footage, all else being equal, and since you’re not increasing square footage rental income won’t increase.If you’re talking about eliminating a living area completely, and renting each room, what you’re created is not a boarding house, but what’s known as SRO, or single room occupancy (a boarding house has a common ( shared) living area, kitchen, dining room at a minimum, and usually additional common areas such as second living rooms, dens, patios.  

Recently (last week)  i added door sweeps, weather strips to all exterior doors and door sweeps to all interior doors which needed them, bought them plastic to install over (new) windows. and have scheduled to get the furnace cleaned professionallyThe market rate of the apartment is 875 and i  am renting it to them for 800 should i be concerned that they are upset about high electric bills,  given i have done more than a slum lord to ensure they are happy and they are 75 dollars under market rat?  

This is total square footage too, including garages and patios.

Next project is adding a patio.