Among piles of old newspapers used as insulation he found a copy of Action Comics No.1, which in 1938, the very year the house was built, had introduced the world to Superman.
Being hidden in the dark for over 70 years had helped to keep the colours bright, but it wasn't a great copy and, according to press reports, the back cover was torn during an argument Gonzalez had with his wife's aunt.
Stephen Fishler of online auctioneers ComicConnect of New York reckoned that little tiff probably wiped at least $50,000 off its value, but this remains the holy grail for comic collectors, and even rated at only 1.5 in the standard CGC grading system, it sold for $175,000 (£112,315) to a "hardcore golden age comic collector" in their June 11 sale.
Damage Limitation
That is far more than Mr Gonzalez could ever have hoped to make on his house, but he now plans to finish fixing it up and keep it. As to that costly damage, he told a reporter that it didn't matter to him that much, and that he would rather work for his money.
Action Comics No.1 has, of course, made far more. In November 2011 a near-mint example with a CGC rating of 9 (out of a perfect 10) was sold by ComicConnect for a record $2.16m (then $1.39m). That was a copy that in 2000 had been among comics stolen from the collection of actor Nicholas Cage, but which 11 years on was recovered from a storage unit in California.
