Frequently Asked Questions
The concrete mix is a high slump 5″- 6.5″ (125 mm – 165 mm) with a smaller aggregate size so the concrete flows easily. The person in charge of placing the concrete should watch the concrete flow throughout the whole wall to ensure there are no void pockets. Internal vibrating provides good consolidation, eliminating voids.
Fox Blocks walls are designed as reinforced concrete walls, with steel reinforcement bars specified to be installed vertically and horizontally, as the walls are built. Typical reinforcement bar sizes used are #4 or #5 (10 m or 15 m).
The EPS in an Fox Blocks has a flame retardant that allows the forms to be flame resistant. The EPS will melt when exposed to sustained temperatures over 300°F (149°C). The ignition point of the melted styrene is 600°F (315°C) (wood is approximately 500°F (260°C). Fox Blocks have been tested to meet the building code requirements for flame spread and smoke development, plus Fox Blocks may be used as fire resistant rated wall assemblies in schools and hospitals.
Test reports conducted by the National Research Council state: “The maximum toxicity index obtained from the combustion of polystyrene was of the same order as that of wood.” Fox Blocks ICFs have been tested to meet building code requirements for flame spread ratings, smoke development and toxicity
Fox Blocks contain a minimum of 40% recycled content by weight.
- Fox Blocks do not off-gas and are not manufactured using any gases that deplete the ozone or are harmful to the environment.
- Fox Blocks require low embodied energy to manufacture.
- Fox Blocks do not contain any materials, that promote mold or mildew growth.
- Fox Blocks are an efficient construction method thereby reducing the amount of construction waste, dust and air pollution in the building process.
- Building with Fox Blocks will save on heating and cooling costs because less air is exchanged between the outside and inside of your home. This also means a smaller more efficient HVAC unit is required for the home.
- Fox Blocks are sustainable. They will not rot or deteriorate for the life of your home.
- Fox Blocks provide a secure, durable, comfortable, long lasting building
Products are not rated or certified under the LEED program. The overall building is evaluated and assigned a LEED rating. In the selection of building materials for a LEED design, Fox Blocks have many benefits that can enable, enhance or directly contribute toward LEED points for the project.
Energy Star does not evaluate or rate insulation products. Every Fox Blocks home when tested by an Energy Rater, can meet and exceed the Energy Star home standards and achieve a 5 Star rating and a ‘HERS’ score well below the minimum Energy Star requirement of 85, or in Canada, higher than an EnerGuide rating of 80.
EPS does not off-gas. Fox Blocks forms do not and never have contained any CFC or HCFC products. The forms are made by a steam process that utilizes ‘pentene gas’ as a blowing agent. The blowing agent dissipates from the product within 48 hours of manufacturing. Fox Blocks forms are odorless, do not deteriorate, and do not off gas.
EPS is an inert, organic material. It provides no nutritive value to plants, animals or micro-organisms. It will not rot and is highly resistant to mold and mildew.
EPS provides no nutrient value and is not a food source for termites. If left exposed, termites may tunnel into the foam in search of fibrous food. When building, in a heavy termite infestation area, care is required in the detailing and construction of the walls that will be in contact with ground, to prevent access to the foam for termites.
Absolutely. The exterior walls are two layers of continuous insulation, the density of solid concrete and a layer of ½” gypsum board on the inside all contribute to superior sound suppression of STC 50 for the whole building envelope. Note: A wood frame system of equivalent STC rating would be 2 x 4 studs spaced 16˝ o/c, with 3½˝ absorptive material, 1 layer of 5 /8˝ Type X gypsum board on resilient channels spaced 16˝ o/c, and 2 layers of 5 /8˝ Type X gypsum board on the other side. (Courtesy of 1995 NBCC Section A9.10.3.1 Wall #W5a)
The plastic webs in Fox Blocks forms are 100% recycled postindustrial polypropylene. The EPS insulation is virgin material. Recycled content for an ICF block is measured by weight. The recycled content by weight of a standard 6″ Fox Blocks form — 48%.
Yes, every component of the Fox Blocks form itself plus the concrete and reinforcement bars are recyclable.
The clear R‑Value of an Fox Blocks is R22, however current Energy codes recognize the lack of thermal bridging in an ICF and the contribution of the mass concrete on the influence of the thermal performance. Whole wall calculations indicate a Fox blocks wall assembly provides an R24 rating.
The continuous double layer (inside and outside) of insulation, the elimination of thermal bridging and minimal air infiltration through the mass concrete wall assembly, allows Fox Blocks walls to performance in the high performance wall assembly category. Completing the envelope with energy efficient windows and doors and roof insulation, Fox Blocks homes can easily meet and exceed energy code requirements and exceed the minimum requirements for Energy Star and EnerGuide. A Fox Blocks structure requires 44% less energy to heat and 32% less energy to cool.
No. The characteristics of an ICF wall with the mass concrete and the EPS insulation provide the required vapor permeance to meet building code requirements as a vapor barrier.
Fox Blocks are compatible with all exterior finish materials and systems – siding, stucco, masonry veneer, simulated stone, etc. The attachment of certain exterior finishing systems is recommended with exterior grade screws fastened into the exposed or concealed webs.
Acrylic stucco is a thin coat finish which can be directly applied to the EPS insulation on the exterior face of the ICF. Fox Blocks provides a continuous EPS surface conducive for the application of acrylic stucco. All acrylic stucco manufactures are familiar with ICFs as a substrate and each have their recommendations for application over ICFs. Note there is a difference in the installation procedures between acrylic stucco and traditional stucco.
Traditional stucco has a thick cementitious base, typically installed over a metal lath. The metal lath is fastened directly to the Fox Blocks webs with screw or staples.
All building codes in the USA and Canada specify that plastic insulation (EPS) must be covered by a thermal barrier equivalent to 15 minutes of fire protection in habitable spaces. This is achieved with ½” gypsum board or an equivalent material. Fox Blocks has specific fire testing that proves regular ½” gypsum board with regular drywall screws fastened into the plastic webs remains on the wall for the required 15-minute time period.
All building codes in the USA and Canada specify that plastic insulation (EPS) must be covered by a thermal barrier equivalent to 15 minutes of fire protection in habitable spaces. If the basement is classified as habitable space, then gypsum board must be applied but does have to taped and filled. Check with your local building official.
Yes, Fox Blocks has a brick ledge form and the xLerator ledge reinforcement that is designed to support masonry. Fox blocks also has a tieKey accessory which is a specifically made as a masonry tie, to be inserted through the form into the concrete.
Fox Blocks are listed in the building codes (IRC- Sections R404, R611 or NBCC Part 9) with specific applicability limits for residential construction. If the project meets the applicability limits within the building code, a Professional Engineer may not be required (dependent on local building department requirements). A building official has the right to request engineering and in some regions all projects require a professional’s stamp. For any projects that exceed the applicability limits, a Professional Engineer is required for the structural design. Check with your local building department.
Fox Blocks has a wide-ranging network of knowledgeable product distributors and trained installers across North America; contact Fox Blocks Customer Service to find the closest Fox Blocks product distributor or trained installer in your area.
Fox Blocks forms have a reversible interlock system on all blocks. The robust interlock allows the blocks to fit together very tightly, eliminating any requirement for adhesives. A reversible interlock speeds up the installation.
EPS is listed basically under four property classifications – Type I, II, III and IV. The characteristics are based on the density of the molded foam which defines the product type. Fox Blocks ICFs are manufactured as a Type II EPS with a density of approximately 1.5 pounds per cubic foot.