Baltimore is one of the great architectural cities of the East Coast. The rowhouses of Federal Hill, the Colonials of Roland Park, the Georgian estates of Guilford, the Tudors of Homeland, the stone farmhouses of Greenspring Valley — these homes represent centuries of building tradition, and they deserve renovation approaches as thoughtful as the craftsmanship that built them.
But renovating a historic home is different from renovating a newer one. The materials are different. The construction methods are different. The approval processes may be different. And what you find behind the walls is almost always a surprise. This guide covers what you need to know before you start.
Do You Live in a Historic District?
The first question is whether your home is in a formally designated historic district. This matters because it determines whether exterior changes require government approval.
In Baltimore City, the Commission for Historical and Architectural Preservation (CHAP) designates and regulates historic districts. If your home is in a CHAP district, you need a Certificate of Appropriateness before making exterior alterations. Some districts also have a District Advisory Committee (DAC) that reviews applications before they go to CHAP. Dickeysville, for example, has a three-layer process: DAC review, then CHAP review, then city building permit.
In Baltimore County, there is currently no county-level historic preservation commission. However, individual neighborhoods maintain their own architectural review standards. The Guilford Association and the Homeland Association both review exterior modifications within their communities. These aren't government bodies — they're private associations with covenants — but their approval matters if you want to maintain good standing in the neighborhood.
Even if your home isn't in a formal historic district, it may still have historic significance. Homes over 50 years old may be eligible for the Maryland Register of Historic Places, and some qualify for historic tax credits that can offset renovation costs.
The Secretary of the Interior Standards
When CHAP reviews your project, they evaluate it against the Secretary of the Interior Standards for Rehabilitation — a set of ten principles that guide how historic buildings should be treated during renovation. You don't need to memorize them, but the core ideas are worth understanding:
Preserve what's original. Don't remove or alter historic materials and features unless they're genuinely deteriorated beyond repair. If original wood windows are still functional, repair them rather than replacing them.
New work should be compatible but distinguishable. An addition to a 1920s Colonial should feel harmonious with the original — matching scale, proportion, and materials — but shouldn't try to fake being original. The goal is honest architecture, not deception.
Be reversible when possible. Prefer modifications that can be undone by future owners without damaging original fabric. This is why CHAP generally discourages removing original plaster to install drywall, or replacing wood windows with vinyl.
These standards are common sense dressed up in bureaucratic language. They amount to: respect what's there, make thoughtful changes, and don't destroy anything irreplaceable.
What You'll Find Behind the Walls
Every old house has secrets, and they usually reveal themselves during demolition. Here's what we commonly encounter in Baltimore homes built before 1950:
Knob-and-tube wiring. This was standard electrical wiring through the 1940s. It's not inherently dangerous if undisturbed, but it can't handle modern electrical loads and most insurance companies won't cover it. If your renovation opens walls, updating the wiring is usually recommended — and often required by code.
Galvanized plumbing. Steel water supply pipes were standard before copper became prevalent in the 1960s. After 60 to 80 years, these pipes corrode from the inside, reducing water flow and quality. If your home has galvanized supply lines, replacing them during renovation is smart — it's vastly cheaper to do when the walls are already open.
Plaster and lath. Pre-war homes were built with plaster applied over wood lath strips, not modern drywall. Plaster walls are actually superior to drywall in many ways — harder, more soundproof, better at resisting fire. Where possible, we preserve and repair original plaster rather than tear it out. Where plaster has failed, we repair with compatible materials.
Minimal insulation. Most homes built before the 1970s have little or no wall insulation. If walls are being opened during renovation, it's an opportunity to add insulation without the cost of a standalone insulation project. Closed-cell spray foam is often the best choice for historic homes because it adds both insulation and air sealing without requiring full wall cavity access.
Previous modifications. Many old homes have been modified multiple times over the decades — walls removed, doorways closed, plumbing rerouted — sometimes without engineering or permits. We evaluate the structural integrity of existing conditions during preconstruction and address any issues in our scope of work.
Not everything behind the walls is a problem. Old-growth lumber framing in pre-war homes is often superior to modern dimensional lumber. These homes were built to last — and they have.
Materials and Methods That Matter
Historic renovation demands materials and methods that are compatible with the original construction. This doesn't mean everything has to be identical — it means everything has to be thoughtfully chosen.
Windows. In CHAP districts, vinyl windows are almost never approved. Aluminum-clad wood windows with simulated divided lites and spacer bar muntins are generally acceptable — they provide the look of original divided-light windows with modern thermal performance. True divided-light wood windows are the purest option but significantly more expensive. Interior windows are typically not regulated.
Millwork. Matching existing trim profiles, door casings, and crown molding requires either finding a match from a millwork supplier's catalog or having a custom profile milled. We work with suppliers who can replicate virtually any profile from a sample piece. When adding new millwork in an addition, we match the species, profile, and finish of the original.
Hardware. Period-appropriate hardware makes a disproportionate impact on the finished feel of a historic renovation. Reproduction hardware in unlacquered brass, oil-rubbed bronze, or black iron is widely available. For truly significant homes, salvaged original hardware can sometimes be sourced and restored.
Exterior materials. Cedar clapboard, wood shingles, natural slate, standing-seam metal, stucco, and stone — these are the materials Baltimore's historic homes were built with, and they're the materials CHAP expects to see in renovation work. Each has specific installation requirements for compatibility with the original building envelope.
The Cost Premium
Historic renovation typically costs 10% to 25% more than comparable work on a non-historic home. The premium comes from several sources: period-appropriate materials (wood windows cost two to three times what vinyl costs), custom millwork replication, specialized labor, longer lead times for custom-ordered items, and the time required for approval processes.
The flip side: Maryland offers historic tax credits for qualified rehabilitation work on designated historic properties. The state credit can be 20% of qualified rehabilitation expenditures for owner-occupied residential properties. The federal credit is 20% for income-producing properties. These credits can meaningfully offset the higher cost of historically sensitive work. Consult a tax professional to determine whether your project qualifies. Read our general cost guide for Baltimore County renovations.
Why the Right Contractor Matters Even More
On a new-construction project, you're building from a blank slate. On a historic renovation, you're building within constraints — physical constraints (existing structure, existing materials, existing conditions), regulatory constraints (CHAP, DAC, building code), and aesthetic constraints (matching a century of existing detail). This requires a contractor who understands not just how to build, but how these homes were built, why they were built that way, and what's worth preserving.
At Samuel Adams & Company, historic preservation is one of our three divisions of service. We follow the Secretary of the Interior Standards, we navigate the CHAP and DAC approval processes, and we bring the management discipline that historic projects demand. Our 20-year warranty means we're committed to the long-term performance of every restoration we undertake.
If you're considering a renovation on a historic Baltimore home, we'd welcome the conversation. These projects are some of the most meaningful work we do — preserving something irreplaceable while making it livable for the next generation.
