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Liquid WRB for joists and beams on a deck

canada_deck | Posted in General Questions on

In the Pacific Northwest, it is becoming more common to use a product like Grace Vycor on joists and beams to reduce water damage and slow down the rate of corrosion of the connector hardware.

https://www.homedepot.com/p/Grace-Vycor-4-in-Deck-Protector-5003029/302451944

I’d like to know if there is a liquid applied product that I could use instead.

Edit to add:  One of the main challenges/requirements is that this barrier must be UV stable indefinitely.

Interestingly, the Grace Vycor product says:
“Do not leave Grace Vycor Self-Adhered Flashings permanently exposed to direct sunlight.”
But the gaps between the deck boards will receive sunlight everyday for decades.

R-Guard Cat 5 says: “May be exposed to weather for up to six months without compromising performance. In ventilated rain screen applications, Cat 5 has indefinite UV stability.”

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Replies

  1. mackstann | | #1

    According to this Grace Vycor Deck Protector brochure https://www.buildsite.com/pdf/wrgrace/VYCOR-Deck-Protector-Summary-Brochure-1602026.pdf :

    Typical deck applications (such as on ledger boards/rim
    joists or underneath joist hangers) may expose GCP
    Vycor Deck Protector only to indirect sunlight (with
    limited intensity) and only for short periods of the day,
    if at all. Such UV exposure is acceptable. The product
    should not be let permanently exposed to direct
    sunlight. It is recommended that GCP Vycor Deck
    Protector be covered within 30 days.

    1. canada_deck | | #2

      Yeah.... so I guess what I am wondering about is if the R-Guard might actually have a stronger UV resistance since they allow the product to be exposed for 6 months before covering.

      1. Expert Member
        MALCOLM TAYLOR | | #3

        That's a really interesting idea, if for no other reason than the strips of membrane often really detract form the way the deck looks - especially from the underside.

  2. Expert Member
    Michael Maines | | #4

    Vinyl flashing could be bent into a consistent U-shape to cover the joists. Somebody should manufacture and sell the U-shaped caps... For special situations I've done it with copper flashing, but that gets expensive quickly.

  3. gusfhb | | #6

    Everyone is always trying to replace metal.

    My deck is supported by large beams that are part of the structure of the house, some parts are cantilevered. Yah just can't replace those.

    Ice and water/ copper/ ice and water.

    where I had pressure treated I used a product that was copper over a self adhered product, we shall see how it holds up.

  4. canada_deck | | #7

    I asked the manufacturer if R-Guard could be used in this way and they indicated it would not be an appropriate use of that product.

    However, after digging around some more, I think that GE Elemax may be a good match. It's a silicone based product so it can be fully exposed to the elements for years.

  5. Zdesign | | #8

    Trex Protect Tape is specifically designed for installing on the top of Treated Joists. Similar to a Grace Vycor tape and it shrinks down on fasteners to keep water out of the joists.

    1. Expert Member
      MALCOLM TAYLOR | | #9

      "it shrinks down on fasteners to keep water out of the joists."

      To me that is the big advantage it and similar solutions have over plastic or metal caps, which might trap moisture with little capacity to dry. I wonder how liquid membrane does at sealing penetrations?

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