Here at the Conservancy, we put a lot of effort into making sure windows and doors at historic buildings are just right. Windows and doors are key features of historic buildings, and modifications to doors and windows can have large impacts on the look and functionality of historic facades. At a typical NYC row house, windows and doors account for about 40% of the facade, so we view them as an important investment.
Here are some tips for repairing or replacing windows and doors at your historic property.
Consider Repair Before Replacement
- Adding storm windows or other glazing protection can be a sustainable alternative to replacing historic windows; storm windows and protective glazing can provide additional insulation which helps with energy efficiency, comfort, sound, and potentially security. Storm windows can be installed on the interior or exterior of buildings.
- Adding or updating the weatherstripping around your windows and doors is an easy and inexpensive way to reduce air infiltration at these openings, providing more energy efficiency and comfort.
Historically Appropriate Replacement
- When repair is not possible or when replacement is the preferred option (for example in the case of existing inappropriate windows, missing doors, etc.), ensuring appropriate replacement materials and design is important. The age, material, and location of existing windows and doors and the originals are key factors in deciding on suitable replacements.
- In addition to the material, design, and operation of replacement windows, the type of glass can also be an important consideration. Window proportions were often an important part of historic architectural styles, and changing the glazing type can affect the size of the frame. For example, replacing single-paned windows with IGU’s (insulated glass units, often called double-pane windows) is a popular efficiency upgrade, but these new windows can have larger frame and muntin sizes that can look awkward at an historic façade.
Permitting
- All modifications to exterior windows and doors on NYC individual landmarks or buildings in historic districts require Landmarks Preservation Commission (LPC) approval. Refer to LPC’s Window Fact Sheet for more guidelines about window projects in landmarked buildings.
- A Department of Buildings (DOB) permit may or may not be needed for your window or door project, depending on the scope. Some modifications that may require a DOB permit may include:
- Changing the operation of the windows or doors (e.g. doors open out instead of in, double doors are being replaced with a single door, windows are fixed instead of operable etc.)
- Any structural work needed in support of your door and window project (e.g. the lintel is being replaced, the size of the windows or doors are changing, or other wall reinforcement or structural work is required at these openings)
- If any of the windows are located on a lot line wall or if there is a change in fire rating on any of the doors or windows
- More information about if a DOB permit may be needed can be found here.
- A licensed architect or engineer is required to be the professional of record for any window or door project requiring a DOB permit.
Qualified Professionals
- Working with a preservation architect or other qualified design professional can help ensure your project is completed with appropriate designs and permits and can add valuable project management expertise, even if a DOB permit is not required. They can also help determine what permits may be required for the project.
- Using a qualified contractor can make the difference between a beautifully completed, historically sensitive, long-lasting project that is easily approved by LPC or a waste of time and money. There are many qualified window and door repair contractors in NYC, as well as manufactures and installers that provide skilled services in appropriate replacement doors and windows; ask the Conservancy for a continually updated list.
For more information about historic windows, the Conservancy published this book that is now available online for purchase.
If you have questions about issues with your building, call our Preservation “Hotline” at 212-995-5260, Ext. 305 or email us at GwendolynStegall@nylandmarks.org