Terracotta has been used for thousands of years. In simple terms terracotta is low fired clay.
Inset details made from terracotta below or between vertical windows stacks such as in this picture, are common in the historic construction of Capitol Hill.
Header failures are not rare in the 100+ year old masonry construction in Capitol Hill.
In some cases the reason for failure is as simple as natural deterioration with age.
If you look closely at the picture, you can see there is a vertical zig-zagging crack in the brick and brick mortar where the structural load path has a differential settlement.
If you look closely at the eyebrow or segmental arches above the windows in the picture, you can see that the bricks in the soldier position around the segmental arch have shifted over the years and are falling out of place at specific locations.
In other cases contractors who did not know about working with historic materials have used the wrong materials and it actually accelerated the degradation of parts of the building assemblies, see a separate post on spalling, click here.
In this photo, you can see a double wythe brick wall cut right down the middle.
Middle English from Old English withthe(“withe”)
A wythe of brick is a single vertical assembly of units. In this case, and typical with above grade exterior or even interior demising walls in Capitol Hill the wall is a double wythe.
You can see a perfect crosection of the bedding mortar and stretcher mortar between bricks. The vertical joint between wythe is the collar joint.
In this picture you can see where a wall was dismantled and you can see a typical functional assembly of common brick. Here is well you can see this is a double wythe brick wall. We’re in the picture above you can see
the bedding mortar between the Shiner faces of the brick, in this picture you can see the prepend mortar, in section exposed, between the rowlock faces of the brick.
You can also see the otherwise, normally completely hidden collar joint between the two wythes.
What is otherwise just simple brick, are used in many ways in our Capitol Hill historic facades to provide variation and accent. Brick set at an angle so you can see both the soldier and sailor faces or the spreader and shiner faces at the same time is called cogging.
Between a window header and a sill of windows above, it is common to see a accent section built into the exterior masonry.
Brick cogging used as an accent.
Roman Brick is long and thin, it is found in a few places in DC and rarely not covered in paint. This house is built with a beautiful example of Roman brick, left unpainted.
Roman Brick in a running bond.