You're on the hook for roof, structure and parking lot, exactly as that clause says. The lease controls, not the flyer.
Strictly, a triple net lease means the tenant pays the three nets: property taxes, insurance, and maintenance, on top of base rent. Loosely, brokers call almost anything NNN if the tenant covers taxes, insurance and day-to-day operating costs, even when the landlord keeps roof and structure. That looser version is very common in medical office. The version you want to read carefully is whichever one is in the document, and the phrase to look for is whether capital replacements are the landlord's or are amortized back to the tenant over the remaining term.
On reserves, a common way to pencil it is a per-square-foot annual number for capital items. On a 6,000 sf building, setting aside something like $0.20 to $0.40 per foot per year gets you $1,200 to $2,400 a year, which is real money but nowhere near a roof. A commercial roof replacement on a small building can easily run $10 to $15 a foot, so $60,000 to $90,000 here. That's why buyers get a roof and HVAC condition report before closing and negotiate on price if the roof has three years left instead of fifteen.
The part that catches new medical buyers is HVAC. Clinics run air handling harder than a normal office because of exam room ventilation and, in some suites, medical gas or imaging equipment cooling. Ask who owns and replaces the rooftop units, and ask how old they are. That's usually the bill that arrives before the roof does.
