If your building was constructed between the eighteen nineties to present, then above any door or window opening in a header lies a lintel. So what is the purpose of the Lintel, you ask?
Well, it’s generally made of cast iron, wrought iron or steel and has the purpose of structurally supporting a facade wall. Therefore, if you have a masonry facade and want to have door and window openings within it, then the use of a lintel can definitely make that possible. However, keep in mind that if the lintel is not properly maintained, then eventually, as it’s going to be exposed to the elements, it will start to corrode.
Types of corrosion
There are currently 8 types of corrosion that lintels may be subjected to, including stress and inter-granular corrosion which you’ve probably become accustomed to already if you watched CSI. When it comes to inter-granular corrosion, it’ll usually occur at holes of susceptible metals, such as iron or steel, but also at unsealed or unpainted edges of the same type metals. As for stress corrosion, this is when cracks within the metal start to appear due to a combined action of applied tensile stress and general corrosion.
Lintels need to be able to resist moisture at the joints with masonry and at their edges because if they cannot, then the steel will start expanding at the edge because of inter-granular corrosion. As a result, the lintel will begin to slowly sag. Keep in mind that both of these kinds of corrosion are eventually going to affect the surrounding masonry and cause window distortion under the pressure, brick displacement, but also in step-crack patterns that are highly visible.
In situation where servicing of such problem has been avoided for too long, extensive repairs will most likely need to be performed. In parts of US where freezing temperatures are part of the weather pattern, seeing those characteristic cracks starting from the upper corners of a window or door opening is very common. For example, for homeowners living in Chicago tuckpointing in such cases might be required at a very minimum. Worst care scenario – you’ll need to have several bricks removed from above the opening and steel lintel replaced to prevent further damage or even failure of the masonry structure.
Removing old sealants
To make sure you won’t have to deal with any type of corrosion, it’s recommended that you start removing old sealants. Next, use a wire brush to brush the rust from your steel lintel and then use a red oxide primer and some exterior paint on it.
Lastly, you need to get some caulk specifically made for use on exterior masonry and apply a layer of it between the brick and the lintel. On the other hand, if stress corrosion or inter-granular corrosion are already very visible, you should consider replacing the steel lintels and hire a professional to repair the surrounding masonry.