The $900,000-per-unit cost of rebuilding Jefferson Park public housing stems partly from extraordinary factors such as bidding and wage requirements for public agencies, the large number of family-sized units, deteriorated utilities and hazardous materials at the site an analysis shows.

Tucked away in the wilds of Cambridge – near Alewife – lies what is essentially the local ninja training center. The building is due to be torn down to become lab space, though, and neither kung fu nor sword skills can hold off the bulldozers. A development moratorium might.

The idea of stopping office and lab space from being added in the Alewife area until city planning is in place passed the City Council in 7-0-2 vote Monday. But that moratorium needs its own process.

When tenants move into the new Jefferson Park Federal public housing development in a few years, they will pay among the lowest rents in Cambridge: about 30 percent of their incomes. The apartments they live in, though, will probably cost at least $900,000 each to build.

The Abbot, a four-story block of retail, offices and restaurants due to open early next year in the heart of Harvard Square, is already signing leases – including one that brought groans from Historical Commission members.

A conversation about freezing the addition of offices or labs near Alewife was cut short Monday, but not before it was revealed that a company called Healthpeak planned to spend an additional $225 million in the area for a total $616 million since August and $949 million within around two years.

Another acre was added Tuesday to the Alewife area holdings of a Denver company called Healthpeak – the 19th parcel the firm has picked up north of Fresh Pond since August for a total $391 million. Some city councillors want zoning in place before labs and offices are debated for the land.

Twelve acres owned by Cabot, Cabot & Forbes in the Cambridge Highlands just sold for $120 million to a Denver firm called Healthpeak Properties, part of $193 million the company has spent in Cambridge in a month.

A bid to keep working into the night constructing the 40 Thorndike office tower project in East Cambridge was rejected unanimously Thursday by license commissioners, who didn’t see the hardship demanded for the variance.

Past debates over setting “linkage” fees for commercial development have divided the City Council into factions who want to push the limits and those who fear scaring off the builders who pay those fees. These was no hint of division as councillors talked about a 66 percent increase.