Aluminum Wrap on Steel Lintels / Big Mistake

I see it everywhere. Otherwise nice and well maintained buildings that have had their windows replaced, and the window installer wraps the structural steel lintel with aluminum.  Ouch.

Lintels are made of steel and they don’t like water.

When you wrap lintels in aluminum,  they remain saturated.  Lintels are supposed to drain and not sealed up with aluminum or caulk.  It dramatically accelerates the deterioration of the steel causing major damage to the adjacent brick and masonry.  Some installers even caulk the aluminum to the brick, making it a certainty that the lintels will rust out in a few years.

Talk to your window contractor.

Window installers have a mandate to make their new windows look good.  That’s fine, but they should not do it at the expense of very expensive to replace lintels.  There are ways to address this, but they are not in any window installers handbook.  If you are anticipating replacing windows, you need to talk to your window contractor how they intend to finish their installation and maintain drainage from the lintel pocket.  What you want is lintels that drain, and no aluminum wrap.


So, what do you do if your lintel has already been wrapped?

My colleagues and I have experimented with drilling small holes in the aluminum to allow water to drain or make alterations to get some air in and the water out.  Fair disclaimer, this is our found solution in ways to fix what someone else has screwed up. It’s not anything recognized by any masonry industry group.  If anyone has come across any clever solutions, please run it by me with a comment below! I’d love to hear your thoughts.



I'm a home inspector and carpenter in Chicago and this site is built from things I’ve learned from 30 years inspecting houses in this town.

'Aluminum Wrap on Steel Lintels / Big Mistake' have 8 comments

  1. May 20, 2018 @ 4:09 pm Garnet

    Interesting post Kurt. Yet another way to mess up a good home. I need to have lintels repaired/replaces this year and wondered are they ever made out of solid Aluminum or another material that won’t rust? It seems crazy to use steel when you know it will inevitably rust.


    • May 20, 2018 @ 5:59 pm Kurt

      Nothing but steel. That said, you double coat the steel with a corrosion resistant paint or epoxy, wrap flashing on them in the manner that’s required by our building code,, and you’ll get a hundred years out of them, at least, which is longer than most folks are going to care.


  2. June 3, 2020 @ 9:49 pm Rafael

    Do not ever wrap steel with aluminum unless you install an isolation membrane, so that the two materials do not make contact with each other. If they do there will tend to be a chemical reaction. This effect is called galvanic corrosion resulting from dissimilar metals and alloys with different electrode potentials, resulting in rusting and deterioration.


    • June 3, 2020 @ 10:15 pm Kurt

      You are correct, but aluminum and iron have a relatively small galvanic reaction. The primary problem is the lintel pocket can’t drain. The whole mess retains water. All problems start with water. You should never wrap the lintel, even with an isolation membrane as you suggest.


  3. December 31, 2020 @ 11:48 pm Hope

    So companies who replace windows know this? Or do they just simply install the window and hope for the best?


    • January 1, 2021 @ 1:01 am Kurt

      99% of all installers think this is how it’s done, if they’re thinking at all. It’s a very rare installer that knows what to do. (I made up the 99% statistic to illustrate just how many guys do it wrong.)


      • March 4, 2023 @ 12:51 am Alex

        Kurt, I like your answers and was wondering if this is something I can do myself. If not, how much would a professional typically charge to replace corroded steel lintels per window?


        • March 4, 2023 @ 1:04 am Kurt

          Sure, you could do it yourself, but it’s a task that is not a first time DIY project. It requires scaffolding, masonry skills, and general logistics knowledge. I don’t know if there are any Youtube videos showing how, but I’ll take a look and see.

          Baseline, if you are seriously DIY and not afraid of hard physical labor, do it. If not, you should hire someone. Lintels on an “average” window, replaced by a competent contractor, is going to be about $1500 per lintel depending on a wide range of variables and the number of lintels, and you’ll find prices above and below that number. A lot of the cost is setup and logistics. Most guys say a minimum of 10 windows to get a decent price.


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