The Historic Masonry Construction of Capitol Hill

Picture of the remaining ruins of the historic kilns, in today’s National Arboretum.

Capitol Hill is a neighborhood built with brick. Almost every street is lined with colorful row homes built about 100 years ago. Though most brick row homes look similar, these buildings were designed and constructed by various builders and architects and there are unique differences between the buildings.

Almost all the bricks you see in Capitol Hill row homes were actually created locally. Because masonry is composed of simple material– sand and clay–bricks can be produced almost anywhere. When complete though, their weight makes moving them from production facility to job site a challenge. The asphalt roads and highways of today facilitate industry-wide logistical options for remote production. However, at the time when this neighborhood was built, the heavy cost of moving mass materials made it more economical to create the brick close to the site of construction.

There were at one time over 100 brickyard type operations in the Washington, DC area. At the National Arboretum you can still view the beehive style kilns that were used in early 20th Century brick production. At their peak they were producing over 100,000 bricks per day.

Brick construction was not simply a choice based on convenience and aesthetic. Urban areas built with lumber were prone to disastrous fires and many cities had building codes which mandated masonry construction. One of brick’s many advantages is that it does not burn, making brick neighborhoods far safer than those built with wood framing.

Finding written historical records about the construction industry at the time that the Capitol Hill neighborhood was built is a difficult process, a lot of what is known has been passed down directly through individuals in the trade today. Thane Timbers of United Building Envelope Restoration based in Northern Virginia focuses on restoration of masonry structures of similar construction to the buildings in Capitol Hill. Thane’s company is currently involved in a reconstruction and renovation project of the National Museum of Natural History.

Timbers points out that the historic methods of firing brick was a less consistent process and among brick piles in a kiln, the outer bricks reached a higher temperature than the bricks stacked in the inner areas of the cube or hack. “The outer brick became stronger in the firing process. Those outer bricks, still to this day, hold up better where exposed to exterior elements. Even today when you look at the contrasting brick, you can strike the brick with a tool and hear the difference. The brick fired at higher temperatures sounds a bit more like metal or glass. The inner fired bricks were still used, but more often used on the interior side of walls or locations where there was less exposure to the elements of weather.”

The Library of Congress maintains some records from days of the operational brickyards and the Godey lime kilns here in DC.

The components of mortar were produced locally as well.   Some of the ruins of the Godey Lime Kilns still stand to this day. Unlike the modern mortar and cement used today, historic bricklayers relied on lime to create the mortar for masonry construction.

Timbers explains some details of the interesting yet little-known history of construction of Capitol Hill buildings. If you look closely at the masonry facades of our buildings you will see a difference in the brickwork at most front facades with tighter mortar joints and more consistently shaped brick. “At the time of much of the construction in DC, the local trade of masonry was evolving, especially as it applied to smaller structures such as the Capitol Hill row homes. A general contractor and team would self-perform as many disciplines of construction as possible. The higher quality brickwork at the front facade with pressed bricks was subcontracted by masonry specialists, often referred to, at the time, as Front Lumpers. Meanwhile the side and rear walls were often built by the general contractor’s lower cost in-house masons.” The pressed bricks that Timbers describes were then, as they are now, more expensive than the common brick used at the other parts of the building.

Creative architectural styles have used brick and terracotta throughout the neighborhood to add ornate designs to what would otherwise be simple looking buildings. Corbel cornices, quoin corners, and arched openings are prolific in the homes of Capitol Hill. Cast iron barnstars prevent structural facade deflection and add a decorative touch. Many buildings were built with a Flemish bond masonry pattern which highlights the skill of the architect and mason.

Although the masonry of our homes in Capitol Hill have aged well considering the many decades that have passed since original construction, maintenance and repair is required regularly. Tuckpointing, to replace the outer areas of deteriorated mortar joints, must be done with a softer mortar than today’s common high strength cement mortars. The local big box stores do not even carry the needed materials, and it is recommended to use a local specialist mason to carry out tuckpointing repairs.

Header Failures
Header failure above windows and doors is common in this neighborhood. Segmented arches, composed of multiple pieces rather than one solid arch, are more prone to failure. If a header fails, it requires shoring and complete reconstruction of the area above the arch, a laborious undertaking.

Gregoire Holeyman is an architect and owner of the local firm Barnstar Architects, specializing in custom renovations and additions to historic homes. Considering the architectural design elements that make these historic buildings unique, Holeyman elaborates on the methods and materials beyond the surface of the brick facades. “Segmental arches are found throughout the Capitol Hill neighborhood. These structural assemblies have stood the test of time, but require regular maintenance. Where you see structural failures at openings, it is often more than just the brick that has degraded. Wood headers were commonly installed behind the masonry arch. When deteriorated mortar joints allow even a small amount of water to enter at the header, the wood part of the lintel system can swell and rot, leading to structural failure and/or step cracking. The seasonal freeze-thaw cycle compounds this deterioration.” This explanation illustrates a perfect example of where a small amount of maintenance can save significantly in what otherwise becomes a large repair.

For more information about historic masonry common in Capitol Hill go to local contractor GL Barnhart Construction’s website: This article was written by Gary Barnhart with help from Miles Curran of the GL Barnhart team.