It is an opinion of Makay…VA/MD/DC/NENC

**swelling steel lintels are common in our area.. one common symptom of this we’ve noticed in our area are cracking along ‘weak points’ of walls that have spans using mid to low grade; raw; carbon steel.. ‘weak points’ are normally window sills and tops of door and window jambs – where they vertically join the next closest one; the top of the wall; or a corner; following the path of least resistance.. this is due to expansion and contraction of the steel because of elemental exposure, higher humidity seasons, and winter nights falling below freezing with the daytime highs being above freezing; resulting in a sometimes constant freeze/thaw cycled season ..  symptoms normally start to appear when the dwelling is 25-30 years old.. one way to combat this as long as possible is by replacing them with hot-dip zinc galvanized steel lintels instead of stainless steel (steel that contains 10% chromium) or carbon steel (a common basic raw form of steel used for building).. galvanizing steel via submerging it in molten zinc forms a metallurgical bond of the zinc and steel, which also coats it thoroughly.. instead of 25-30 years of corrosion free steel; the hot-dip zinc galvanized steel will last 40-70 years corrosion free in our Southeastern Virginia region..**