So when the development team found out about the artist in their midst, they were intrigued. “How many people have come to the New York market saying, ‘We’re a gallery, it’s great for art collectors,’ ” said Leonard Steinberg, the broker at Compass who is handling sales, speaking of new developments. Now, thanks to Mr. Osmanaj, he said, “this is a building with art in its DNA.”

Sensing interest, Mr. Osmanaj offered to present his portfolio to Dov Barnett, a founding partner of Tavros, who had taken a liking to his work. “I thought he’d come in with a big folder with his work,” Mr. Barnett said. “He basically took the next day off from work and brought 15 large canvases to the building and set up like his own gallery space within an apartment.”

The stunt nearly got the artist fired by his boss, the tile contractor. But after Mr. Barnett explained that he was responsible for Mr. Osmanaj’s absence from his tile work, the artist was brought back on the job with the stipulation that there would be no more shows until construction was complete.

“He has a delight in creation which is fresh and authentic,” Adam Gordon said in an email in June. “I hope he has the opportunity to share his gifts.”

Now that the building is almost complete, and all but two apartments — the $12.65 million penthouse and a $7.95 million four-bedroom — have been sold, nearly all Mr. Osmanaj’s artwork has either been taken down or covered up, including a huge self-portrait on a wall of a master bathroom he helped tile over himself.

“In 10 years, if someone decides to take a wall down,” said Mr. Zahn, the general superintendent, “they’re going to open it up and maybe actually see part of a painting.”

Through the end of August, a few of Mr. Osmanaj’s paintings, which incorporate his trowel technique, can be viewed at Life Gallery on West 27th Street. The gallery focuses on discovering and promoting emerging artists and was created by Nicolas Saint Grégoire, an artist and designer, and Hervé Senequier, who works at Compass with Mr. Steinberg.

In the meantime, Mr. Steinberg of Compass has raised the possibility of hanging some of Mr. Osmanaj’s free-standing work in the penthouse for a marketing event. “Someday he will be a star and we will be regretting we didn’t etch it out of the walls,” he said.