GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Exterior door with bronze aluminum threshold over copper sill pan – galvanic corrosion?

ia42 | Posted in General Questions on

We have a front entry door with water damage issues like those mentioned in the GBA article,  ‘Sill pans for exterior doors’.  The article mentioned that copper sill pans are good, but I’m wondering about galvanic corrosion.  One quote we got was for a Thermatru fiberglass door with a bronze aluminum threshold over a copper sill pan.  Prior to receiving the quote, I happened to read about copper and aluminum being two metals that when used together would result in galvanic corrosion.

Any thoughts? (Thanks!)

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

  1. Expert Member
    Michael Maines | | #1

    Ia42, this is one of many charts available online that show the potential for galvanic reaction between dissimilar metals. It shows that yes, galvanic reaction is likely to occur if aluminum and copper are in contact with each other. You could just add a separation layer of Vycor (a butyl membrane) or similar between the metals; if they aren't in direct contact and not sitting in water the reaction won't occur, or will be slowed to the point that it won't matter.

  2. Tom May | | #2

    If you add an insulator as Michael suggest maybe you can add some wiring and charge some batteries at the same time :)

  3. Expert Member
    Akos | | #3

    If I remember correctly with copper and aluminum it is the aluminum that will corrode over time. The threshold has a lot of material there, I think it will take a very long time with a lot of standing water to have issues. The earlier suggestion of peel and stick between the two would eliminate any worries.

  4. Expert Member
    Peter Engle | | #4

    Or you could use one of the plastic sill pans available on the market. Or, just form the sill pan with Vycor and skip the copper. I've seen the inside dam of a copper sill pan sweat in the winter because it's pulling so much cold from outside.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |