Self-storage buildings are popping up all over the state.

“It’s sort of like tulips; they’re growing everywhere,” said Irving Patterson, a founder of the Maine Self Storage Association “I think it is related to people looking for a place to invest their money.”

And Maine is seeing the very beginning of mini-storage compared to other states that have already seen units overbuilt, he said.

“I think it is related to people looking for a place to invest their money.”

It’s a shift nationwide from stock market and mutual fund investments, he said.

In some states and big cities, there are hundreds of self-storage facilities, he said, including some that are several stories high, with elevators and parking for customers.

Profitability of a venture depends on location and demographics, he said.

An area with a lot of apartments, condominiums or lakes has a higher need for this service, he added.

If there were fewer apartments and fewer condominiums, there would be less of a need.

Some numbers that investors consider to see if an area could support a mini-storage building is 3- to 5- square feet of mini-storage per capita.

That means if there are 7,000 people in a town, it could support 21,000- to 35,000-square feet of mini-storage, Patterson said. The size of the units is “pretty flexible,” he said.

Patterson and his wife, Loreen, who is the president of the Maine Self Storage Association, formed the group two years ago.

Initially, there were 10 to 12 members. It’s grown to 41. The state association is a member of the national Self Storage Association.

Patterson, who spoke by phone from his winter home in Florida, said that in some states self-storage units have already reached the point of over capacity.

“What happens when you build too much,” he said, “is you only have them partially occupied. In some places, it’s already overbuilt.”

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