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

Roof structure for a submersible house

grosscat | Posted in GBA Pro Help on

We are building a roof structure on a house in the flood plain of Lake Travis.  The plan is to build a roof that is breathable on both sides of the roof deck which will be pressure treated plywood or marine plywood.  The roofing material will be metal standing seam.   What kind of underlayment should be used on the roof decking under the lath strips that the metal roof is attached to?  I am thinking that the underlayment should be highly permeable so that the decking can dry to the outside as well as the inside should it become submerged.  My builder want to use felt or tar paper, I think it should be something like Vent 3 or Brea by Nemo industries. Please advise.

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.


  1. Expert Member


    Usually houses are built above the flood-plane, and I've seen a couple in architectural periodicals from the Netherlands that were designed to float during flooding, but I've never heard of a house that can be successfully submerged. Has this ever been done, or is this something you are proposing trying for the first time?

  2. GBA Editor
    Brian Pontolilo | | #2

    Hi Cathy.

    Like Malcolm, I'd love to hear more about this project. For now, you could also consider the Pro Clima Mento products. They are robust and vapor-open:

  3. grosscat | | #3

    Our home is a 100 year old house built like the Alamo, solid stone. The only wood elements will be some pressure treated wood at windows, and the roof trusses and structure. The only sheet rock will be paperless in ceiling. Certainly that would need to be replaced if flood waters ever got that high, but while awaiting water to abate, it would not harbor mold growth. The water is clear, clean and with minimal movement due to it being on a lake floodplain. Kitchen cabinets will be King Starboard, a polyethylene like plastic. Etc. While this house is not a prototype for a flood-able house, it is the best we can do to mitigate damage and mold. The roof is unlikely to be submerged, but could be. I'm just trying to preserve a metal roof and substructure and keep things as healthy as possible. More flood resistant building research needs to be done as floods are certainly becoming more frequent, just ask Houston. I will look at the Pro Clima Mento products. Thanks

    1. Expert Member
      MALCOLM TAYLOR | | #4


      Thanks for the reply. That's a fascinating problem to try and solve. Unfortunately I have no useful advice to give. Hopefully other posters have some relevant experienced and can help.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |