You want something breathable so water can reach the roots but strong enough to suppress weeds.

I'm aware of the fire suppression, ADA needs, etc. 

not sure if its helpful for your planning/designs......We generally need a mix of grade and dock doors, need 18'clears, must have fire suppression (doing flooring and carpet distribution usually) and generally need little to no office. 

(I'd likely need to displace the tenants in the existing 2 units)He said I could file an appeal with the state to just add the necessary fire suppression systems to the basement since the existing 2-family just had its smoke alarm system re-wired. 

Macroeconomics are suppressing spending, combined with a massive overbuilt supply of properties.

But let's say we're looking at it at our current market where things are somewhat suppressed, on the low end I'm seeing 5 cap and on the higher end a 10 cap or a little more. 

Keep in mind the defaults and distressed sales that flow from them will further suppress cap rates until all of that inventory works its way out of the market and investors don't see more of it on the horizon.

Fire suppression & sprinklers?

You disregard the suppression of economic activity caused by universal tariffs.

Not to stop the triplex dreams here but a traditional connected triplex in Houston is subject to the commercial building code (fire suppression systems and such).