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Musings of an Energy Nerd

New Lakesideca Products — July 2012

A housewrap that encourages drainage, a new liquid-applied water-resistive barrier, polystyrene inserts to improve the R-value of ICFs, and a better way to install manufactured stone veneer

Adding more insulation to an ICF. Boost-R panels are rectangles of EPS foam than can be inserted into an insulated concrete form to improve a wall's thermal performance.
Image Credit: Reward Wall System
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Once again, the “in” box on my desk is beginning to fill up with a stack of brochures describing interesting new products.

I’ve selected four products to review in this latest roundup: an insert panel to improve the thermal performance of insulated concrete forms (ICFs); a new wall system for manufactured stone veneer; and two new water-resistive barriers (WRBs).

Polystyrene panels to improve the performance of ICFs

A manufacturer of insulated concrete forms (ICFs), Reward Wall System of Omaha, Nebraska, is now selling polystyrene panels that can be slipped inside of ICFs to improve a wall’s R-value. This product will prove useful, since many ICFs have a relatively low R-value.

Called , the new foam rectangles come with notches that slide over the ICF form ties and rebar chairs. Of course, these Boost-R panels take up room that would normally be filled with concrete. So if you want to use these insulation inserts, you’ll need to order ICFs with thicker-than-usual cores. If you ordinarily use an ICF with a 6-inch-thick concrete core, and you’d like to insert 4 extra inches of foam on one side of the wall, you’ll need to order ICFs with a 10-inch core.

Boost-R panels are 2 inches thick and are available in several different densities (1, 1.5, and 2 pounds per cubic foot). If you want more than 2 inches of extra insulation, it’s possible to insert two layers of 2-inch thick Boost-R panels inside the core of a thick ICF.

The manufacturer claims that its 1.5 pound/cubic foot polystyrene has an R-value of R-4.17 per inch. That means that a 15-inch ICF with a 10-inch-thick core equipped with a 4-inch-thick Boost-R panel can have an R-value of R-38.

Two-inch-thick Boost-R panels cost between 95¢ and $1.85 per square foot, depending on the foam density and the quantity ordered.

Of course, there is a simpler way to obtain high-R ICFs: just order ICFs from a Logix, one of Reward Wall System’s competitors. Logix has a line of high-R ICFs called the . This type of ICF is available in a variety of sizes, with R-values up to R-66.

EnduraMax wall system for manufactured stone

A producer of manufactured stone, Oldcastle Architectural, has developed a manufactured stone veneer wall system that incorporates a layer of R-9 expanded polystyrene foam (EPS). The system, called , appears to do a good job of addressing the weaknesses of many manufactured stone veneer installations, many of which have failed due to inward solar vapor drive problems that turn OSB sheathing to oatmeal.

The EPS layer should safely interrupt inward solar vapor drive. Since the back side of the EPS includes parallel vertical grooves — the 1/2-inch-wide grooves make up about 50% of the back surface of the foam — the system allows for some drainage, hygric redistribution, and ventilation between the foam and the wall sheathing.

The EPS panels used in the EnduraMax system are installed with screws and special stainless-steel anchors that act like washers.

The EnduraMax system works with several styles of manufactured stone, concrete brick, and clay brick veneers. The average thickness of these concrete and fired clay veneer products is only 1 3/4 inch. The EPS wall units include recessed pockets designed to accept these thin concrete or clay tiles. Once the veneer units are snapped into place, the wall is ready for grout.

HydroGap is a new draining housewrap

Housewrap manufacturers offer many wrinkled, crinkled, or bumpy housewraps designed to encourage drainage. These include , , , , and .

The latest such product is from Benjamin Obdyke. HydroGap is a polypropylene housewrap with three-dimensional plastic polka-dot nubbins. These nubbins help maintain a gap of 1 millimeter (between 1/32 inch and 3/64 inch) to encourage water to drain downwards. [Author’s note: see Mike Guertin’s comment below. Mike notes that some types of siding compress the HydroGap nubbins enough to raise questions about whether the product actually drains well after siding is installed.]

One advantage of using nubbins instead of parallel grooves: the housewrap drains in all orientations, even when installed diagonally.

The main purpose of HydroGap is to perform as a water-resistive barrier (WRB). However, if the product’s seams are taped and penetrations are sealed, it can also serve as an air barrier.

HydroGap is a little thicker than Tyvek StuccoWrap, but considerably thinner (and therefore cheaper and easier to install) than products like Home Slicker Plus Typar than incorporate a three-dimensional plastic drainage mat.

HydroGap has a vapor permeance of 14 perms. The product is sold in 500-square-foot rolls for about 17¢ per square foot.

A new liquid-applied water-resistive barrier (WRB)

There are several brands of liquid applied WRBs on the market, including , , , and . The latest product to enter the market is from Tremco Barrier Solutions.

Enviro-Dri is asphalt based; the manufacturer refers to the product as a “modified asphalt emulsion.” The product is applied in the same manner as most liquid-applied WRB:

  • Cracks and seams are sealed with a special sealant (Enviro-Dri Joint Sealant);
  • Wide seams and window openings are reinforced with tape (Enviro-Dri Joint Fabric); and
  • The entire exterior surface of the wall sheathing is coated with the liquid (Enviro-Dri Field Membrane), using a brush, trowel, roller, or spray equipment.

Tremco advises builders to shim rough window sills to drain outward before installing Enviro-Dri Joint Fabric. No primer is needed when using Enviro-Dri.

According to the manufacturer, Enviro-Dri is suitable for use on plywood, OSB, or 1/2-inch-thick fiberboard. The sheathing must be dry and dirt-free at the time of application. The acceptable temperature range for application is from 0°F to 130°F. The product can’t be applied in the rain.

Installers aim to apply the product at a wet thickness of 12 to 15 mils; this application rate yields coverage of 110 to 130 square feet per gallon. Enviro-Dri cures in about 8 hours under favorable weather conditions. It can be left exposed for up to 4 months before it needs to be covered by siding. Enviro-Dri is compatible with all types of siding.

The permeance of Enviro-Dri is 12 perms, so it is considered vapor-permeable. Although Enviro-Dri works as an air barrier and WRB — in fact, the ability of these liquid-applied WRBs to reduce air leakage is one of their best features — the manufacturer notes that the “Enviro-Dri WRB system does not, by itself, seal penetrations through the sheathing.” In other words, penetrations still need to be flashed; the manufacturer provides flashing instructions.

Although Tremco trumpets the fact that no fasteners penetrate the company’s WRB system, it should be remembered that, like all WRBs, Enviro-Dri will be penetrated by fasteners as soon as the siding is installed.

Enviro-Dri has been , which determined that Enviro-Dri is an acceptable alternative to asphalt felt. (Asphalt felt is the WRB required in the International Residential Code Section R703.2.)

Last week’s blog: “How to Insulate a Basement Wall.”


  1. John Klingel | | #1

    interesting ICF blocks
    ICF inserts are interesting, but I still wish they'd just make the blocks w/ 4" or 6" on the outside and be done w/ it. Inserting blocks and ordering larger ones sounds spendy; I wonder how it compares to screwing or gluing 4" rigid foam onto the outside of a smaller ICF.

  2. User avater
    Paul Eldrenkamp | | #2

    new is not always useful
    With the exception of windows and mechanical equipment, I'm pretty sure I could cost-effectively build a durable home to Passive House standards using only materials that were available 30 years ago.

  3. Jesse Lizer | | #3

    ICF R value
    Oak Ridge r values are rather outdated, Martin. I am not sure if an R-12 ICF even exists any longer. Average foam forms are from 22-28, with most being right around r24.
    Even then it is on the low side compared to the 20,40,60 idea. I am toying with using the forms for the strength, sound and tightness but then furring out the interior with stud and insulating with batts or roxul. its cheaper to furr it out then to add more foam on the exterior of the form. Plus furred walls on the interior eliminates running the electrical in the foam, makes attaching things like cabinets and trim easier, etc. Do this can get your walls mid r30s and push r40.

  4. Jason Miller | | #4

    Quad-Lock ICFs
    Have you looked at Quad-Lock ICFs? A local architectural firm is a dealer and used them recently for high R-value walls. They look like one of the better ICF products. They offer multiple configurations of panels and ties to build up to R-84 ICF walls.

  5. Mike LaCrosse | | #5

    In reference to the Quad-Lock ICFs by Jason
    The R-84 ICF walls Jason mentioned are interesting, but what I wonder is are they cost effective? I haven't looked into the cost or construction of these particular systems Jason mentions, but I would think that building an R-84 foundation might be pricy. There is a diminishing return with insulation, and especially so, since foundations are mostly below grade and partly insulated by the ground around it already. With that in mind, is it worth shelling out the extra cash to achieve an R-Value that high?

  6. Barry Dale | | #6

    ICF's with foam only on exterior
    TF Forming Systems makes an ICF with the ability to use foam only on the exterior. I think they have up to six inch panels for the exterior.

  7. Jesse Lizer | | #7

    to Mike
    ICF are not only for foundations. They are typically used for foundations because you typically need concrete anyway, so they are a good way to get a good rvalue below grade. However they are often used above grade but are typically not recommended on this site due to most being around r24, which is considered quite low by most's standards here. Above grade they are strong, quiet, fire resistant, mold, bug and animal resistant, air tight, allows one to have a continuous air barrier and insulation from footer to roof.

  8. Mike LaCrosse | | #8


    You're right. Being more accustomed to most residential applications, that is where my mind immediately jumped

  9. Paul McGovern | | #9

    Just an aside - Most buildings subject to USACE Protocol testing specify that all spray-applied liquid air-barriers also be rolled for greater adhesion; I assume this would be true for Enviro-Dri. Many then require ASTM D4541 pull-off/ adhesion testing at 1 dolly per 1000 sq' of surface area.

  10. Aj Builder, Upstate NY Zone 6a | | #10

    Rock paper scissors Huber Zip
    Rock paper scissors

    Huber Zip beats sprayed asphalt IMO.

    Just like acrylic tennis and driveway coatings beat the less expensive asphalt emulsions. Asphalt coatings dry out and crumble over time. Never good long term in tennis courts anyway.

    Thanks all for the ICF ideas. TF Forming sounds interesting.

  11. User avater GBA Editor
    Mike Guertin | | #11

    HydroGap Caution - Fibercement Compression
    The bumps on HydroGap are soft and I've found them to compress when blind-nailing fibercement lap siding. The top corner squashes the gapping material so siding pretty much touches the wrap. This isn't a problem unique to HydroGap - others seem to compress under the top edge of fibercement too.

    Most demonstrations of drainging housewraps use a clear flat acrylic sheet that distributes evenly across the housewrap surface which gives a false impression of how each performs beneath various sidings used in the real world.

  12. kim_shanahan | | #12

    The logic of Logix
    Martin, it would seem Reward Wall has come up with a solution to a problem - their product isn't that great to begin with. I saw Logix at IBS two years ago and was very impressed. It seems the perfect solution for high-mountain builders in our market building in climate zone 7. Most build on sloping sites with ICF crawl spaces. Also a big fan of Nu-Dura because of their collapsible web design. The embodied energy in shipping a truckload of feather-light ICFs is cut in half since they fold flat. Pretty nifty.

  13. User avater GBA Editor
    Martin Holladay | | #13

    Response to Mike Guertin
    Thanks for your comments about the compressibility of HydroGap housewrap. I agree with you: if the nubbins are compressed by the siding, they aren't doing any good.

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