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Footing capillary break product

airfix | Posted in General Questions on

What are the thoughts on using a foundation wall waterproofing material for a capillary break between the footing and the foundation wall?

Something like Tremco Watchdog H3?

It seems like it will cure quickly and can be applied in cold weather and will be readily available on the job site for waterproofing the wall.


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  1. canada_deck | | #1

    I would be hesitant to use a product that was not designed for that application given that this is a permanent decision that can never be redone.

    Some considerations:
    - This is basically a squishy product. The two surfaces that you are squeezing this between are not 100% smooth and the pressure is immense (the weight of the concrete wall.) Imagine this product being peanut butter squished between two pieces of burnt toast in a clamp. Are you realistically going to maintain the 60 mil thickness everywhere or is it going to squish down to almost nothing in some places and 120 mils in other areas?

    - The product is rated to a spec based on hydro-static pressure which is a bit of a different scenario than what you are trying to block with a capillary break.

    Have you tried asking the manufacturer if they recommend the product for this application.

    In my opinion, if they thought it was going to perform well in that application they would pay to do the few extra tests and advertise it accordingly.

  2. GBA Editor
    Martin Holladay | | #2

    You should read this article: "Capillary Breaks Above Footings."

    As the article notes, either asphaltic dampproofing or Tremco TremProof 250GC are possible products to consider. I don't know much about Tremco Watchdog H3.

  3. airfix | | #3


    I did read that article and not being sure of what asphaltic damp proofing is I thought this was a similar type of product and similar to that Henry CM100 that is also recommended. My contractor wants to use what he has on hand and it seemed like a good option but I have no experience with this kind of product.

    Canada_Deck there were a few products that were recommended in the article Martin linked that were not specifically "capaillary break" products but products that could be used for that effect. After all what we are looking for is something that can seal the footing pores and voids, will last a long time, can be applied to below grade surfaces and is water impenetrable.


    1. Expert Member
      BILL WICHERS | | #6

      Asphaltic damp proofing is a tar-like material that is commonly applied to the exterior of basement walls (the side in the ground). It’s smeared on as a heavy coating that looks like black stucco. The stuff has been around pretty much forever.


      1. airfix | | #7


        Yeah that's what I thought it was and my contractor uses that Tremco Watchdog H3 for the same job so it seems like it will work well as a capillary break. Nobody, uses a capillary break here. I mean nobody. Everyone thinks I'm nuts and is looking at me strange so I'm pretty much on my own here trying to figure it out without looking like a complete numpty.

        1. Expert Member
          MALCOLM TAYLOR | | #8


          The watchdog H3 will work fine. Oh - and full marks for using the term numpty. It's an underused descriptor.

  4. airfix | | #4

    FYI the recommended HenryCM100 suggests to coat a horizontal layer tp 110mils.

  5. user-7022518 | | #5

    We were planning on using the Delta product: Has anyone else used this? Lisa

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