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Best waterproofing to be used over ICF walls

Steve Lenertz | Posted in Energy Efficiency and Durability on

Just put up the ICF walls and filled with concrete on our well insulated house in Zone 7. Was planning on using Grace Bituthene. It seemed to work well on another storage building constructed with the same ICF walls.

The area is properly drain tiled, and the house is in a fairly well drained area to boot.

Just wondering if there is maybe something better out there?



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  1. User avatar GBA Editor
    Martin Holladay | | #1

    First of all, are you talking about above-grade walls or below-grade walls?

    I'm going to assume you are talking about below-grade walls, since those are the type of walls where waterproofing questions are most relevant.

    Point #1: You have to follow the recommendations of the ICF manufacturer. To the best of my knowledge, every ICF manufacturer provides instructions for waterproofing below-grade walls. Consult those instructions and follow them.

    A little bit of web surfing reveals general recommendations as well as specific recommendations from certain manufacturers. Rather than following this advice, you should follow the advice provided by the manufacturer of your ICFs -- if only to avoid possible problems with any warranty.

    One manufacturer, BuildBlock ICFs, recommends:

    "There are many waterproofing systems from which to choose. Some are widely used with results you can count on and others are newer methods designed to save labor and material costs. Some of the newer spray-on membranes for ICF may have success based on the regional skills of the applicator so research your options and results before choosing one. Waterproofing options include:

    - A self-adhesive 60 mil membrane such as Tamko TW-60. This can also be used in conjunction with a dimpled membrane such as DMX-AG to protect the waterproofing from backfill and provide additional hydrostatic pressure relief. This product is available from BuildBlock.
    - An ICF compatible spray-on membrane. (Caution: Do not use a petroleum based paint or primer. These products will dissolve the EPS foam.)
    - A one-step mat type protection (ex. SuperSeal, DMX-AG). This type of plastic mat provides an air gap between the ICF wall and the surrounding earth.
    - As hydrostatic pressure increases it will displace the air and allow the pressure to be released and avoid attempting to penetrate the wall. It works in many locations that have soils that perk or drain well. May require a membrane in some areas.
    - Other locations that hold water require both the membrane (self-adhesive , roll-on, or spray-on), plus the DMX-AG type mat."

    A rival manufacturer, FoxBlocks, recommends:

    "Fox Blocks recommends either the air gap or drainage type systems. Fox Blocks does not recommend the spray, brush, or trowel-on waterproofing systems for the following reasons:
    - They typically do not hold up as well over time
    - They dry to a lower mil coverage
    - They do not cover gaps in the wall
    - They may have small pin-holes in the membrane.

    "While there are many different products on the market, Fox Blocks specifically recommends the following waterproofing membrane systems or an equivalent:

    1. Cosella-Dörken’s Delta MS (or equivalent)
    This is an air gap waterproofing membrane system. It is a tough, dimpled 24-mil high-density polyethylene wrap that seals out water and bridges inevitable foundation gaps. It has full code approval with Canadian evaluation reports. If any moisture gets behind the Delta MS it will self drain to the footing and drain tile. The dimpled side must be installed facing the foundation wall. The Delta MS system comes in rolls and is installed by wrapping the foundation wall and mechanically fastening it with course thread screws near the top of the foundation wall with speed clips at every plastic stud. No damp proofing spray is required. Follow Cosella-Dörken’s attached installation guidelines for the Delta MS system.
    2. Polyguard’s Polyguard 650 System
    This option should be used only in areas where there are termite concerns. Polyguard’s 650 ICF peel and stick waterproofing membrane is a 60-mil self-adhering membrane consisting of 56 mils of rubberized asphalt laminated to 4 mils of polyethylene. It is available in rolls of 4' x 50' (4.22 x 15.24 m) or 39.36" x 61' (12 x 18.6 m). Polyguard also offers a 650XTM or 650XTP product. These two products provide both waterproofing and termite protection.
    For very heavy, hard-to-drain soils, Fox recommends that you use the Polyguard 15P drain system in addition to the 650 waterproofing membrane. This system will relieve hydrostatic pressure. Follow Polyguard’s installation guidelines.
    3. Resisto by Colphene Soprema – a peel and stick self adhered membrane.

    "It is essential to follow the waterproofing manufacturers' application procedures."

    1. EnvelopeGuy | | #6

      Resisto by Soprema - not a colphene branded membrane. Resisto branded ICF Foundation Membrane. Soprema has a membrane but for commercial contractors only.

  2. Joe Mah | | #2

    Look up and research PolyUrea Coatings.

    I have thought about the subject of water proofing ICFs quite a bit and I think this spray applied polyurea coating is the best solution I have found. I even believe it is THE best below ground water proofing solution for any type of construction. It is mostly used in industry and commercial construction (flat roof water proofing). It is the material in truck bed protection coatings/liners like Line-X. In a few markets, it IS used as below ground residential water proofing, but it is not common everywhere. I think it was even featured in this past This Old House season as a below ground water proofing method to bridge connection between an original field stone foundation and new concrete foundation for an addition.

    There are hundreds of types of polyurea formulations to provide the exact characteristics needed for it's application, including flexibility in expansion and contraction. So, any below ground water proofing formulation is likely different than the truck bed liner formulation.

    When I discovered this product, I thought it would be even be a great to use as a WRB and air barrier if you were to build a REMOTE insulation style house. It would easily seal around any penetrations and windows. But I have since learned of Prosoco R-Guard which I believe is superior.

    Hope this helps. I'd also be interested to see if anyone else has an opinion on polyurea spray coatings as a water proofing barrier.

  3. Joshua Terry | | #3

    Could the theory of waterproofing over foam insulation of ICF below grade also be applied to a retrofit exterior foundation insulation/encapsulation with EPS? I am currently trying to find the best solution for waterproofing 4" of EPS on exterior crawl space walls. It makes sense to me to keep the foam dry.

  4. User avatar GBA Editor
    Martin Holladay | | #4

    Q. "Could the theory of waterproofing over foam insulation of ICF below grade also be applied to a retrofit exterior foundation insulation/encapsulation with EPS?"

    A. Yes.

  5. EnvelopeGuy | | #5

    RESISTO ICF Foundation Membrane is specifically for ICF walls. No primer needed for ICF walls either.

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