The city of Miami’s historic preservation office has compiled a lengthy, detailed report that substantially bolsters the case for designation of The Miami Herald’s “monumental’’ bayfront building as a protected landmark based on both its architectural merits and its historic significance.

Somewhat unusually, the 40-page report by city preservation officer Megan McLaughlin, which is supplemented by 30 pages of bibliography, plans and photographs, carries no explicit recommendation to the city’s preservation board, which is scheduled to decide the matter on Monday.

But her analysis gathers extensive evidence that the building’s history, the influential executives and editors associated with it, and its fusion of Mid-Century Modern and tropical Miami Modern (MiMo) design meet several of the legal criteria for designation set out in the city’s preservation ordinance and federal guidelines. A building has to meet just one of eight criteria to merit designation.

A spokeswoman for the city’s historic preservation office said there is no obligation to make a recommendation and the city’s preservation board didn’t ask for one.

Supporters of designation, including officials at Dade Heritage Trust, the preservation group that has received sometimes withering criticism from business and civic leaders for requesting designation, said they felt vindicated by the report, even as they concede that persuading a board majority to support it remains an uphill battle.

“It’s important that an objective expert is saying basically the same thing we’ve been saying, particularly in an environment where there is so much pressure,’’ said DHT chief executive Becky Roper Matkov. “It’s very hard to refute. When you look at the building’s architecture and history, it’s so blatantly historic, what else can you say?’’

The report also rebuts key pieces of criticism of the designation effort leveled by opponents of designation, including architects and a prominent local preservation historian hired by Genting, the Malaysian casino operator that purchased the Herald property last year for $236 million with plans to build a massive destination resort on its 10 acres. The newspaper remains in the building rent-free until April, when it will move to suburban Doral.

Citing federal rules, McLaughlin concluded that the building dates to its construction in 1960 and 1961, and not to its formal dedication in 1963. That’s significant because it makes the building legally older than 50 years. Buildings newer than that must be “exceptionally significant’’ to merit designation under city regulations. Opponents of designation have claimed the building does not qualify because it’s several months short of 50 years if dated from its ’63 opening.

The property also has a “minimal’’ baywalk at the rear but there is room to expand it, the report indicates. The building is considerably set back from the edge of Biscayne Bay, between 68 feet at the widest point and 23 feet at its narrowest, the report says. That’s comparable to what many new buildings provide, thanks in part to variances granted by the city, and could blunt criticism that the Herald building “blocks’’ public access to the bay.