Glass Options for Historic Homes in the DMV

The Washington DC metro area has some of the most extensive historic preservation regulations in the country. DC's Historic Preservation Review Board (HPRB) regulates exterior alterations in historic districts, including window changes. Montgomery County, Arlington, and Alexandria have their own historic preservation programs.

In DC historic districts (Capitol Hill, Georgetown, Shaw, and many others), exterior window replacement typically requires HPRB review and approval. The general guidance prioritizes repair over replacement and requires that replacement windows match the historic character of the original.

If your home is individually listed on the National Register of Historic Places or in a local historic district, consult with a preservation specialist before making any window changes.

For historic homes, glass repair is usually the first and preferred option. Re-glazing (replacing dried or missing glazing putty), hardware repair, weatherstripping addition, and glass patching can extend the life of original windows significantly.

Original single-pane glass, particularly wavy or textured historic glass, has historical and aesthetic value. Some preservationists argue that the imperfections of old glass are part of the building's character and should be preserved when structurally possible.

Interior storm window inserts are a preservation-friendly option for adding energy performance without altering the historic exterior appearance. They mount inside the existing frame, are virtually invisible from the street, and add significant thermal performance.

When replacement is necessary or approved, several glass options respect historic character while providing modern performance.

Restoration glass is manufactured to replicate the subtle waves and imperfections of historic hand-blown glass. It is available from specialty manufacturers and is accepted by most preservation review boards as an appropriate replacement material.

For approved double-pane replacements in historic properties, thin IGUs with slimmer profiles can approximate the look of single-pane windows better than standard IGU systems.

Flush glazed systems (no visible frame at the glass edge) or very slim sightlines help replacement windows read as authentic when viewed from a distance.

Document your existing windows thoroughly before any work begins: photographs, measurements, glass type notes, and hardware documentation. This record is valuable for the review process and for ordering appropriate replacement materials.

Engage a glass contractor with historic window experience who understands the review process. Virginia Glass Windows has worked extensively with DC HPRB-reviewed projects and historic preservation requirements throughout the DMV.

Budget for the review process — HPRB review takes time and may require multiple submissions. Work with your contractor and possibly a preservation architect for guidance on what is likely to be approved.