TAMPA — You've heard of tiny houses. Now Tampa could become one of the first places in Florida to have tiny apartments.

Urban Core Holdings, LLC is under contract to buy a 12-story downtown office building and convert the top eight floors into micro-apartments. Each would have a kitchen with a two-burner stove top, microwave hood, refrigerator and dishwasher. The apartments would also come with a stackable washer-dryer unit; a bike rack and a Murphy bed that transformed into a dining table during the day.

All of this in 300 to 400 square feet for about $850 a month, far less than for other downtown apartments that are fast becoming unaffordable without two occupants to share the rent.

"We think that there is a certain group of people that don't want a roommate, and this is a great opportunity for somebody to live by themselves, save on the expense of a car and live downtown,'' Omar Garcia, Urban Core's manager, said Wednesday.

As the financial hub of the booming bay area, Tampa has a large and growing number of downtown workers — 66,500, including about 13,300 who are under 35, according to a study done for the company. Almost 44 percent of all downtown workers have expressed an interest in living downtown.

Although the project is expected to take up to a year to complete, Urban Core will start accepting reservations Monday for 200 Madison, the building at the corner of Madison and Franklin Streets that now houses a Subway, a Pita Republic restaurant, a CVS and second-floor offices. All of that is likely to remain but plans call for a new common space for residents on the third floor with a gym, pet care area, cafe and balcony overlooking the street.

The mostly vacant fifth-through-12th floors will be converted into 120 apartments, each with ample windows, Garcia said.

One potential drawback that could raise the cost of the project and the rents — the lack of parking.

"We will not have any parking because the idea is that the residents of this particular community will use mass transit, bike share and ride share and are willing to give up their cars in order to live downtown,'' Garcia said.

City regulations, though, call for one parking space per unit, and Urban Core could have to pay a one-time fee of nearly $1 million because it can't meet that requirement.

"We are going to try to negotiate that with the city,'' Garcia said. If the fee isn't totally or partially waived, the rents could rise by about $100 a month, though they still would be substantially less than for downtown apartments that are only slightly larger.

Zach Ames of Tampa's Franklin Street brokerage said the mini apartments might well be attractive, especially to recent college graduates who want to live downtown but can't afford mega rents.

"I think this does offer the option for that live, work, play environment,'' Ames said. "Is the timing right? I don't know, but as Tampa continues to build out with more and more projects, I think it's something that will happen.''

Would Ames, 28, live in a tiny apartment? "Yeah,'' he said, "especially if I was right out of college.''

This is the second multi-family housing venture for Urban Core Holdings. It also owns the 135-unit West River Flats near downtown, which it bought in 2014 and renovated into what have become popular apartments for University of Tampa students. The company runs a shuttle from the apartments to the university, and would probably do the same for students renting in the new project, Garcia said.

While long popular in densely populated, high-cost Asian cities like Hong Kong, micro-apartments also have started catching on in Boston, Seattle, San Francisco and other U.S. cities as rents soar.

In 2013, New York City got its first micro apartment building, with 55 units as small as 250 square feet.

Two years later, New York Mayor Bill De Blasio proposed shrinking the city's 400-square-foot apartment-size limit to under 300 square feet as part of an ambitious plan to build or preserve 200,000 units of affordable housing, according to the New York Post.

De Blasio's announcement came as 60,000 people applied for only 14 below-market-rate micro apartments in the Kips Bay area.

And in Miami and Orlando, developers have tentative plans for micro apartments although those apparently have not yet come to fruition.

If Tampa's tiny apartments "get off the ground, we'd probably look to expand throughout the Southeast'' Garcia said.

Susan Taylor Martin can be contacted at smartin@tampabay.com or (727) 893-8642. Follow @susanskate