Historic structures require significant repair and upkeep – but with routine maintenance the time and expense associated with those repairs can be substantially reduced. Equally important as maintaining the structure is making sure that those repairs are safe for historic buildings. Often, preservation-safe repairs cost the same or slightly more but can save property owners in the long-run. These preservation best practices are not a comprehensive or complete guide to every issue a property owner will confront but are a jumping off point for your next preservation project. 

Before you Begin

The Secretary of the Interior’s Standards are one of the foundational pillars of most preservation projects. First established in the 1960s, they set the basis for how preservationists have come to think about their work. The standards vary based on the type of the project – whether it is preservation, restoration, rehabilitation or reconstruction. Definitions of these types of projects and the full collection of standards can be found HERE 

In general, these standards encourage first doing no harm. For historic buildings that means keeping changes to historic fabric to the absolute minimum and avoiding the unnecessary removal of important components, finishes and structural details.

Additionally, the standards emphasize repair over removal of features. Windows are a primary example of this theory in practice – repairing historic windows is always the best option and provides the greatest environmental and efficiency benefit to the historic homeowner.

Furthermore, the standards explore the challenge of adding new additions to historic structures. In all cases the goal is to blend new construction without damaging or removing historic fabric while at the same time not copying the historic resource and differentiating new construction through various means including different materials, scale, proportion, or massing. 

Common Issues to Consider

For structures built between the 18th  and early 20th centuries there are several common issues which regularly create challenges for repair and maintenance.

The following three issues only scratch the surface but represent the most common pitfalls confronting historic property owners:

  • Masonry Repair: The overarching goal with all masonry work is to match existing materials whenever possible. Specifically, this includes the color, quality, material and texture of brick and stone – and the same type of mortar. Modern mortar mixes available from home improvement stores are generally a bad fit for historic masonry. Mortar high in Portland cement is very hard and will cause historic stones and bricks to fail and crack. Once a modern mortar is introduced to a historic building there is no way to fix the mistake without causing more damage which is why this is an extremely important mistake to avoid in advance. Working with a professional mason well-versed in preservation can help to avoid this common mistake. DIYers can send their existing mortar out for analysis to replicate a mix ratio suitable for their historic building. LimeWorks offers a well-regarded analysis service as do several other firms.
  • To Repair or Not Repair Historic Windows: It is very rare to find a historic wood window which cannot be repaired. In many cases DIYers with a small amount of training can do the repairs themselves. Repairing is always preferred over replacement because historic windows are the “eyes” of a structure – they are critical to maintaining the historic appearance, and, most importantly their replacement with inferior modern materials is always a losing bet economically. Wood windows that are in good repair can be made as energy efficient as a modern window – and when coupled with an exterior or interior storm window they can be even more efficient. Repairing a window also costs far less than a new window and has a very short payback period. Vinyl, fiberglass and cheap modern windows will fail long before they ever repay themselves in reduced energy costs. No matter which way you slice it – saving your wood windows is always the best choice. Attending a hands-on window repair workshop is a good first step. The Window Preservation Alliance maintains a list of workshops and contractors in your area if you are unwilling or unable to start your own repair project. 

NOTE: Most historic windows contain lead paint and should be treated with great care and in accordance with the EPA and OSHA Standards for lead safety.

  • There is No Such Thing as Maintenance-Free Siding: Vinyl siding companies have made a fortune off the idea that synthetic siding is maintenance free. Of course, there is no such thing as a maintenance free product and by replacing wood siding with vinyl, fiberboard or other synthetic siding you are losing one of the primary historic features of your home. Vinyl siding gets dirty, cracks and must be repaired – and if applied overtop historic wood siding may create serious moisture retention issues. It is always best to keep your historic wood siding and repair, repaint and enjoy it! You will never regret this decision and your neighbors will appreciate your dedication to the look and heritage of your home. 

Finding More Information

Every building is unique and has its own challenges. Fortunately, there is a large amount of material available online for historic property owners looking to learn more before they tackle the next big project. 

A good first place to begin is with the National Park Service’s Preservation Briefs. The fifty Preservation Briefs provide guidance on preserving, rehabilitating, and restoring historic buildings and can be found online HERE.

Looking for even more detailed information about specific case-studies on a challenging resource or building feature? The National Park Service’s Preservation Tech Notes are a good place to look to see if your issue has been dealt with before. They can be found online HERE.

Making your building energy efficient is a critical component of any preservation project. Fortunately, energy efficiency need not sacrifice historic integrity. Learn more about how to weatherize and conserve energy HERE.

Looking for a preservation contractor? PreserveList.org, powered by Preservation Maryland, is an online directory of contractors who do the work of preservation and can be found HERE.

DISCLAIMER: Inclusion on PreserveList does not constitute the endorsement of any company, service, or product by Preservation Maryland. Anyone seeking the services of providers included on PreserveList are strongly encouraged to request additional information, qualifications, and quotes before selecting and compensating any entity.

Financial Resources For Preservation

Historic preservation projects can be expensive. However, most projects don’t have to be tackled all at once – in fact the best projects are often phased. Initial efforts should focus on keeping rain out and addressing critical structural issues.

Funding for preservation projects in Maryland include:

  • Federal Historic Tax Credit: The federal tax credit applies only to income producing properties and there are several property-valuation requirements which limit the availability of this 20% federal tax credit to large-scale preservation projects. The program is administered by the National Park Service and applications must be made well in advance of any construction. 
  • Maryland Historic Tax Credit: Administered by the Maryland Historical Trust, certain structures may qualify for a tax credit against qualified rehabilitation expenses. Applications for tax credits must be submitted in advance of any work and it is highly recommended to speak with the staff of the Trust to discuss your project and how to apply for a tax credit well in advance of planning or beginning any work. 
  • Local Incentives: Many counties and municipalities offer owners of certified historic structures incentives (often in the form of a tax credit on property taxes) to assist with the rehabilitation of their properties. Similar to the state’s historic preservation tax credits, these credits impact local tax liability and can be used in addition to the state and federal credit, if applicable. Contact your county planning office to learn about what incentives may exist in your community. 

DISCLAIMER: Preservation Maryland and its affiliates do not provide tax, legal or accounting advice. This material has been prepared for informational purposes only, and is not intended to provide, and should not be relied on for, tax, legal or accounting advice. You should always consult your own tax, legal and accounting advisors before engaging in any transaction.


Perhaps nothing in preservation causes as much confusion as the National Register of Historic Places. Does it prevent demolition? Does it protect buildings? Can you change your paint color? Do you get tax breaks? Can you get a grant? Learn more about the National Register here