Header failure is the partial or full collapse or deterioration of a door, window, or opening in a masonry wall.
Masonry deteriorates over time as a result of hydration, exposure to elements, and is negatuvely affected by freeze – thaw cycles and weather conditions. The pictures below show a granite stone masonry header which has partially collapsed. This type of header failure is somewhat uncommon but nonetheless is influenced by the same factors and requires a similar type of repair.
In the picture below you can see an example of a failed header to the left with a with a intact header to the right, for reference.
The picture below shows the failed header, from a closer position. You can notice that there is a stairstep crack that runs between the field header and the sill above. The stairstep crack in this case is related to related to lateral deflection of the wall of the wall has bowed and shifted out of its original shape.
In the picture below you can see an even closer view of the failed header. The granite stone has cracked and partially fallen from its original position. The bricks above are dependent upon this header to span and support the bricks above the opening. In this case the bricks will lose their integral cohesive strength and will also collapse above the header. You can see where 2 specific bricks have already fallen from their position in the wall.