We don’t yet know exactly what sparked the fire that ripped through the upper floors of the Treadmark building on Dorchester Avenue last week. A Boston Fire Department investigation aimed at determining the cause remains unresolved a week later.

There are serious questions that remain to be answered as this investigation unfolds. What exactly sparked the blaze? Why didn’t the fire suppression systems— set to be tested last Thursday— kick in to beat back the earliest flames? What role, if any, did the construction materials used to build the structure play in its fiery demise?

Early indications are that the mixed-use building might have to be largely deconstructed and built anew as a result of the damage from last week’s long-duration event. If true, that’s a tough setback, but it’s one that this neighborhood can and will endure.

The decades-long effort to improve and revitalize this corner of Dorchester has seen its share of fits and starts, of roadblocks and road bumps. Make no mistake, though: The neighborhood has been through far worse and has come through stronger, wiser, and, maybe, a little tougher.

That’s not wishful thinking. It’s fact.

The people who funded and planned the Treadmark’s construction — Trinity Financial, Inc.— are our neighbors. They have earned our respect and friendship over many years and many projects, from the redevelopment of a former industrial site — now a busy supermarket— to the creation of a new mixed-income, diverse community on the grounds of the old Chronic Disease Hospital in Mattapan.

Before last week, Trinity was best known locally for the Carruth, the five-story, mixed-use building that stands on what was once a forlorn MBTA parking lot. The Carruth is a model for transit-oriented, mixed-income housing and retail in Boston’s neighborhoods. The Treadmark — named with a nod to the site’s history as a tire shop— was designed and built to be the Carruth’s sibling.

The building was set to house a much-needed market, American Provisions. The top two floors, full of condominium units, were already sold. The units on floors two through four were rented to income-eligible people selected through a city lottery. That’s 83 new units of housing in total— with 51 rentals available for people who make “up to 60 percent of the Area Median Income (AMI).”

The Treadmark housing formula is a deliberate move to strike a balance between encouraging new development and retaining a mix of income levels. It is far from what one Boston Globe columnist last week characterized as “a monument to gentrification.” If anything, the Dorchester people who helped to guide this project over three years— from conception to construction— went to great pains to ensure that this building would welcome families from all walks of life— including the many who have called Dorchester home for decades.

Even as the fire continued to rage last Wednesday, Jim Keefe from Trinity Financial pledged to rebuild.

Dorchester will rally around that cause, and not just because Keefe and Trinity have accumulated much good will over many years of working to improve this neighborhood. What’s the alternative? Leave a scarred shell of a building or an empty lot?

Dorchester is moving forward— not backwards. We’ve seen our share of tragedy. Last week’s fire was a setback, not a tragedy, so let’s get about the business of rebuilding Treadmark.