I was so pumped for the demolition phase of my remodeling project that even before we signed the contract, I took a sledgehammer to a partition wall, hoping to discover a pristine crown molding behind it.

Demolition is all about discovery. Occasionally, you do find an original detail or some other hidden architectural gem, though I had no such luck. Too often, the surprises are the unwelcome kind, things like termite damage, dry rot, and other structural issues that will quickly wreak havoc on a remodeling budget. As general contractors like to say, “We can’t see through walls.”

A recent Consumer Reports survey of general contractors put hard data behind the question: “What are the main issues that can lead to cost or time overruns on a residential project?” The biggest culprit, cited by 42 percent of the contractors, was existing structural damage.

“I’ve seen projects where the building had to be condemned following demolition because of too many serious problems,” Federico DiMattia, my general contractor, told me during our first walk-through, as he shared the findings from the demolition phase of my renovation project, involving a 134-year-old Brooklyn brownstone.  

The demo itself had been fast and furious, carried out by a four-man crew over the course of seven days. Wielding crow bars and sledgehammers, they tore down plaster-and-lath walls, ripped out bathrooms, removed a '70s-era kitchen from the rental apartment, and more—enough to fill three 20-yard dumpsters.

Going into it, like many homeowners before me, I’d been holding out hope that my project would be different—that those statistics about hidden surprises applied to other people and that our brownstone had somehow escaped the long, steady tug of gravity, not to mention the butchered framing and accrual of injuries that bear witness to the sins and shortcuts of past renovations.  

But as the dust on the demolition phase settled, allowing our structural engineer to carry out his inspection, it soon became clear that our home would not be an exception.

Fortunately, the engineer’s report didn't turn up anything catastrophic, but there are definitely issues we didn’t account for—in either the timeline or the budget. Below are four nasty little surprises we'll have to address. For floor plans of the project, along with a full overview, see "How to Get Started on a Stress-Free Home Renovation."

Demo Details

  • Four floor joists on the parlor level were notched out at some point, probably to make room for an earlier plumbing line. Especially since the joists will support the new kitchen, with its heavy appliances, cabinets, and foot traffic, they need to be reinforced from below with additional load-bearing studs and then doubled up, or “sistered,” with new supporting joists.      

  • A section of brick wall at the back of the house where the new French doors will go is unstable. That means the steel support beam going there must be longer and will require more work to install (it will span all the way to the neighbors’ walls on either side). The added labor and materials, of course, mean added costs as well.

  • On the second floor, there’s a long crack running along a main structural beam, called a header, connecting the floor joists to the wall. This header will need to be replaced and several of the floor joists will need to be sistered.

  • On the garden level, a water leak threatens to eventually compromise a steel support for an existing beam, so it will need to be addressed.    

The engineer’s report was definitely a bummer, but despite my wishful thinking, we’d been bracing for the worst, and everyone agreed this was pretty much par for the course. In terms of scheduling, the additional work puts us back probably a week or two. As for the cost, it’s adding roughly 5 percent to our bottom line, but we had added a 20 percent cushion to the initial budget, so on paper we’re still ahead of the game—for now at least!

That’s been the biggest takeaway thus far on the project: You can’t prevent hidden surprises on a remodeling project, but you can—and should—prepare for them.   

And the demolition wasn’t all bad news. It also revealed beautiful—if a bit banged up—strip wood floors in the front hallway that we hope can be restored. Compared with the cost of new flooring, which is in the current budget, salvaging the old floors might actually end up saving us some money while also bringing back another aspect of the building’s 19th-century splendor.

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Planning for a Home Renovation