It is common to see lintels over the garage car door to begin to sag. I’ll talk about common problems with lintels. To the left you’ll see a diagram of common lintel issues for windows, but the principle is the same for garage doors, or any opening into a home with a brick veneer.
Lintels are also known as headers.
Mortar or masonry deterioration can, of course, lead to failure. Building settlement may allow the arch to open up and drop. Another problem is forward movement of the arch out away from the building. This is usually caused by foundation movement or mortar and masonry deterioration. Corrective actions include rebuilding the arch or adding a header.
Headers may be undersized for the load. Inadequate end bearing of the headers may lead to failure. Steel headers (lintels) on masonry walls should extend at least six inches beyond the opening on either side. This cannot usually be seen. Steel lintels are subject to rust.
The rusting steel expands and may cause horizontal cracks in the mortar joints at the corners of the opening. Wood headers are susceptible to rot and insect attack. Concrete and stone headers are subject to cracking or spalling.
In amateurish construction projects, windows may be added to masonry walls or brick veneer walls with no arch or header provided. This will often work in the short term, but problems usually develop over time. Missing or inadequate headers should be replaced.
Steel headers (lintels) supporting brick veneer should have no caulking between the steel and the brick above. Caulking may trap water and rust the steel.