Does EPS ‘off gas’?
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.
When is a Taper Top form required?
Taper Top forms are specifically designed to provide a larger bearing surface along the top of the wall. Typically, the increased bearing surface may be used to support masonry, floor or roof loads. Taper top forms are used in the transition from ICF to wood frame construction and the taper top form would be the top form on the wall.
Does expanded polystyrene (EPS) present a serious fire hazard?
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.
Is the Fox Blocks form recyclable?
Yes, every component of the Fox Blocks form itself plus the concrete and reinforcement bars are recyclable.
Do ICFs require a special concrete mix design?
The concrete is normal strength, minimum 2500 psi (20 MPa) per building codes. The mix design specifies a smaller aggregate and higher slump than concrete typically used for floors. Most Ready-Mix suppliers are familiar with an ICF concrete mix design.
Is an ICF home quieter than a stick framed home?
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)
Does the EPS provide support for a wood sill plate?
No, the EPS has no structural capacity to support any loads. Wood sill plates must achieve the required bearing from the concrete within the ICF. A wood plate that cantilevers 1⁄3 over the EPS and bears 2⁄3 on the concrete is allowable. This can be done with a minimum 2 x 6 plate. If a 2 x 4 plate is required, a taper top form should be used to extend the concrete under the plate.
How do I apply traditional stucco to an ICF?
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.
Do ICFs promote mold or mildew growth?
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.
Is EPS the same as XPS?
No, these insulation products are quite different. EPS is closed cell expanded polystyrene, while XPS is a closed cell extruded polystyrene. The properties, applications and costs of each are quite different. The majority of ICFs are manufactured with EPS.