Is burning EPS toxic?
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
What is a ‘blow-out’?

A blow-out’ is a break in the form, gen­er­al­ly due to the pres­sure from the liq­uid con­crete dur­ing the con­crete place­ment and/​or con­sol­i­da­tion. Fox Blocks ICFs are designed to main­tain a high safe­ty fac­tor of pres­sure from the liq­uid con­crete. Dam­aged forms or fail­ure to sup­port areas where forms have been cut leav­ing a large area of EPS between the web sup­ports may cause a blow-out. Over con­sol­i­da­tion may also cause a blow-out.

Fox Blocks rec­om­mends the Pre-Place­ment Check­list be reviewed for all wall assem­blies pri­or to the place­ment of con­crete, to find poten­tial prob­lem areas and install addi­tion­al strap­ping or sup­port to pre­vent blow-outs. Gen­er­al­ly, for an Fox Blocks form, the size of a blow-out may be lim­it­ed to the EPS between the webs, 6″ or 8″ wide by the height of one form. If a blow-out occurs, the con­crete pour moves to anoth­er area on the wall, the hole is patched by replac­ing the EPS, installing wood sup­port over the area, and then resum­ing the pour.

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.
What do termites do to the foam?
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.
Is an ICF house faster to build?
The assem­bly and place­ment of con­crete may take the same time as to build with con­ven­tion­al meth­ods. The advan­tage with Fox Blocks is that the walls are now insu­lat­ed, have a vapor and air bar­ri­er installed and are ready for fin­ish­es once the win­dows and roof are installed. These ben­e­fits will save weeks and/​or months depend­ing on the size of the projects.
What is the typical Interior finish on an ICF?

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.

What fasteners are recommended for ICFs?

Fox Blocks has con­duct­ed numer­ous fas­ten­er tests for pull-out strength and shear capac­i­ty for var­i­ous fas­ten­ers – screws, ring shank nails and sta­ples into the plas­tic webs. The rec­om­men­da­tion for inte­ri­or and exte­ri­or appli­ca­tions of fin­ish mate­ri­als is for the use of screws which pro­vide the best hold­ing capac­i­ty into the plas­tic webs or fas­ten­ing strips in the forms which are iden­ti­fied on each block.

The EPS insu­la­tion does not pro­vide any hold­ing capac­i­ty for fas­ten­ers.

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.
How much will it cost per square foot to build an Fox Blocks ICF home?

Build­ing with Fox Blocks ICFs pro­vides you with a high per­for­mance wall sys­tem for the foun­da­tion and above grade walls. Build­ing any high per­for­mance home, with either ICFs or con­ven­tion­al wood fram­ing, has many fac­tors that define the end cap­i­tal costs.

What addi­tion­al mate­ri­als and labor are required to make a con­ven­tion­al foun­da­tion equiv­a­lent to an Fox Blocks ICF foun­da­tion which exceeds ener­gy code require­ments in most loca­tions? Con­ven­tion­al wood fram­ing requires con­sid­er­ably more mate­r­i­al, insu­la­tion and atten­tion to air seal­ing to make it qual­i­fy and per­form as a high per­for­mance wall. All of this, for con­ven­tion­al con­struc­tion, adds mate­r­i­al and labor costs to the over­all project. Fox Blocks ICFs pro­vide a sim­ple method to build high per­for­mance walls that pro­vide ongo­ing ben­e­fits from the high insu­la­tion val­ues and mass con­crete walls that are ener­gy-effi­cient and pro­vide cost sav­ings for the life cycle of the build­ing.

Com­par­ing cost per square foot between con­ven­tion­al con­struc­tion and ICFs for a high per­for­mance build­ing, is like com­par­ing apples to oranges. To devel­op con­struc­tion costs, more detailed infor­ma­tion is required, for instance the num­ber and size of open­ings, the shape and size of the home, the region­al costs for mate­r­i­al and labor, etc. If you have a project you’d like us to review and pro­vide a mate­r­i­al esti­mate, Fox Blocks would be hap­py to have one of our rep­re­sen­ta­tives con­tact you. Please com­plete and sub­mit a lead infor­ma­tion sheet on the web­site or call Cus­tomer Ser­vice.

What is the R-Value?

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.