Assumption 1:  If the tenants pay their own utilities the expense ratio should be around 30% (in a well run park)Assumption 2:  if the owner pays the utilities the expense ratio should be around 40% (in a well run park)Assumption 3:  Do math for a 10 Cap-it works for any Cap rate you choose including  positive or negative*************************************************************************************************************************Net operating income=gross income - expenses Using the expense ration of 30%  => Net Operating Income*(1-expense ratio)=> NOI*(1-.3)Therefore:NOI/yr=(#lot)*(rent per lot per month)*(12 month per year)*(1-expense ratio)Cap Rate=NOI/Purchase pricedo some 8th grade algebra followed by some 6th grade math (dividing with a decimal)Purchase price=NOI/Cap rateTherefore:Purchase price{tenants pay utility}={#lots*Monthly Rent*12*(1-.3)}/0.1 =>84* lots * rentPurchase Price {owner pays utilities}={#lots*monthy rent*12*(1-.4)}/0.1 =>72*lots*rentThere are the 72/84 numbers derivedIts not rocket surgery.  

White plastic, black letters.

Mine is a bit high but I have had seven knee surgeries , one shoulder surgery.

It doesn't cost me much if any more, just some plastic, masks and paperwork.  

You can read a book about doing surgery but it doesn't mean you're prepared to do surgery.

you could actually put plastic up before the studs and then staple and. duct tape , then use  regular insulation . i guess depends on what its being used for and where you live as well . i have seen kits on eBay and amazon , may  not be worth it ????

Both my landlord and his wife have a lot going on with hospital visits, heart surgeries and him having Alzheimer's disease that they do not mentally care any longer for their investment. 

We did not charge him for it, because our contractor cleared it with one of those long plastic snake things and removed a clump of hair.

Be suspicious of replaced plastic  plumbing at the hot water heater and under sinks.

Disclaimer: This is based on adding a door in a single-family home in Missouri; the requirements for multi-family and in other jurisdictions are probably different.If you have any electrical outlet boxes in the fire-rated wall, they probably need to be steel, or the fancier plastic ones... the cheap blue ones aren't rated for it.If you have to bring a pipe through the fire wall, there may be some requirements about that.