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.”