Preserving the Craftsmanship of Historic Masonry Headers

Today we are looking at window and door openings in masonry partitions.  On the surface it might sound like an obvious and basic topic, but it’s actually quite complex when you look at the evolution and history.  Supporting masonry headers, built with relatively small masonry units were a revolutionary breakthrough point in human history. 

The picture below shows a Roman arch at a door opening in a thick rustic looking stone partition.   Roman arches are one of the first types of self-sustaining arches, made with the same relatively small or comparatively small uniform masonry units.  The design is highly effective because unlike other types of opening headers which require teams of worker to lift heavy monolithic header units, this design can be assembled with relatively small units, by a team as small as a single worker.

Cro-magnons were cavemen, but unlike neanderthals which were close to us homo sapiens, neanderthals were actually a different species.  During the ice age, both species were considered cavemen.  Cro-magnons later left the caves and became modern man.  Window and door headers were a part of that change and evolution.

Relatively early on, many thousands of years ago humans started using masonry, all over the world near simultaneously in a phenomenon known as multiple invention.  Several times in human history, different isolated groups of people throughout the world have near simultaneously developed similar technology in isolation.   Building masonry buildings with doors and window openings changed their development and futures drastically. This type of construction is an example of one of those phenomenons of multiple invention. 

A header is basically an element that spans across an opening and allows brick to structurally bear on top of the door window without crushing or collapsing on top of the door or window.  One of the simplest ways to create a door window header is to use wood timber. Wood is abundant in many parts of the world.  Most type of natural wood, though, lacks inherent resistance to deterioration from exposure to moisture.  For building to last for many generations, wood-built structural headers were not enough.

The picture below shows a segmented arch in a historic brick structure, here in Washington, DC.  This one happens to be built with two courses of bricks in the rowlock position.  

The next one below is very similar, also a segmented arch, with two courses of brick set in the rowlock position.  One of the big differences though is that the one below has been repointed already, yet that repointing work was done using a relatively sloppy methodology.

The window header below is also a segmented arch, but unlike the one shown above, the one in the picture below has three individual courses of bricks in the rowlock position. Similar to a Roman arch, the segmented arch, with its larger radius curvature, has a degree of intrinsic self-stabilization.  One of the differences though is that the segmented arch is not entirely self supporting.  It does require some internal structure to provide support.   

In simple terms, a Roman Arch is self supporting because of the weight of the header itself and the load above bears down onto the arch which, because of its shape, pushed the force outward at each side against the adjacent portions of the wall which work like an abutment to resist the lateral thrust of the arch.  

The window header shown in the picture below is similar to a segmented header, with a relatively wide radius arch, but this particular header has bricks set in a soldier course position.  Even when set with bricks run in a horizontal line below the arch itself, the segmental arch still has a purpose.  It works to receive or reduce the majority of the pressure or force of the mass of the brick above. Then, the brick below and the segmented arch can work in combination to increase the overall resistance and longevity.

The next header shown below is a jack arch header. The jack arch header runs almost horizontal, but the arch does actually have a degree of internal stability.  If you look closely at the bricks and the header shown below, particularly at the bricks at the left and right side of the jack arch header, you may notice that these bricks are not perfectly right angles, they’re actually made in a skewed format and have been rubbed or custom cut to a specific shape which allows the bricks to be set on a slight angle.

The jack arch is yet another example of a different type of historic arch, used to support the weight of the building wall above an opening.  However, the picture below shows signs of failure. Much of the different parts of the brick at this wall have already been repointed. The mortar has deteriorated over time and selectively, some of that mortar has been specifically replaced through a spot repointing or tuck pointing process.  The signs of the past failure are visually apparent.

In this coming week’s blog, we’ll look at several different examples of Window and door headers that have already failed and or partially collapsed. From looking at those examples, we can learn a lot about the pressure enforce imposed upon masonry headers.

We can Help

Our company focuses on historic restoration more than modern building upkeep, maintenance, and construction, but our company understands both types of construction very well and a full picture well-rounded approach is needed in any niche in the construction industry.Although we focus on historic restoration, repointing, tuckpointing and historic brick repair, our company also has technical knowledge and competencies in the areas of modern and contemporary construction as well as we become one of the leaders in that area of the market today.Understanding both historic and modern or contemporary construction is useful because both aspects help understand the challenges and potential solutions for challenges in building science and construction.

We can help with a variety of historic masonry restoration needs and upkeep, from modest tuckpointing and or repointing to complicated and extensive historic masonry restoration. Infinity Design Solutions is a historic restoration specialist contractor specialising in both historic masonry restoration such as tuck-pointing our re pointing, and brick repair.If you have questions about the architectural details or facade of your historic building in Washington DC, reach out and say hello and if we can help we’ll be glad to assist you.You can email us or call us on the telephone at the following link: contact us here.