Have you been seeing stars in your Washington, D.C. neighborhood? If you’ve noticed metal stars set against the beautiful brick facades of the area’s historic homes, you have a good eye for detail. While they may look like small pieces of art and offer an interesting exterior surprise, these stars serve a more critical function. If you’ve ever questioned why these stars are a commonplace sighting as you walk around D.C., or why they may be a feature of your own house, it’s time to discover more about how they came to exist in the first place.
The Metal Stars on Your Home Are Anchor Bolts
The metal stars on your home's front and back façade are called anchor bolts. Anchor bolts serve a vital structural purpose—they hold historic brick buildings together. Typical row houses were designed to ensure that as many families as possible could fit in one area, with each home still having a fair amount of square footage. It wasn’t only people sharing walls with their neighbors—rowhouses spread structural loads through shared framing. Although it allowed for quicker builds and lower costs, the walls began to bulge over time, especially at the front and back. To repair the bulging and prevent future structural concerns, anchor bolts (and anchor plates) were engineered.
Why the Historic Brick Walls Were Bulging
Unlike the shared joists that run across walls and distribute tension across multiple points, historic brick homes' front and back walls are usually only supported by relatively weak connections at the edges and roof. This was the cause of the bulging brick problem.
Compression and tension are the two main forces involved with the bulging brick walls. Compression squeezes materials together, while tension stretches the materials and pulls them away from each other. Brick, like concrete, has excellent compressive strength, but less so under tension. Metal, on the other hand, performs well under tension. Combining the two materials of brick and metal anchors made perfect sense and corrected the problem.
How Anchor Bolts and Anchor Plates Work
Metal anchor bolts and anchor plates work by redistributing the structural forces at play on your home’s walls. To correct the bulging brick and shore up the weak connection, large anchor bolts (also known as tie bolts) were placed through the brick and into the structural joists. The anchor plate (sometimes called a wall washer) is connected to the bolt and distributes tension over multiple bricks. This stabilized the walls and prevented further problems.
Star-shaped bolts worked extremely well at redistributing tension thanks to their broad, radiating shape. Other common shapes also worked well, including diamonds and circles. Square shapes were often the least expensive option, as they were easier to produce. Sometimes square anchor plates were tilted and resembled diamond anchor plates from afar.
Once the issue was identified and corrected, builders started using tie bolts during the construction phase to prevent the problem from occurring in the first place.
What Else Can These Stars Tell You?
The stars on your house can tell you a lot about its history. They can give insight into your home’s age, whether the bolts were part of the construction or part of a repair, and sometimes even how expensive the house was to build. This can be especially helpful if you are looking into the history of your home or seeking a historical designation—every piece of information helps. Even if you’re not tracing your historic brick home’s past, you can rest assured that your home’s structure was indeed a top priority in the past, as it still is today, and enjoy those beautiful stars even more.
Contact Renaissance Development, the tuckpointing experts in D.C., to arrange a consultation for restoration and repair of brick, both outside and inside your historic brick home.
