Can you build and pour concrete in cold weather?
Yes. The forms insu­late the con­crete and enhance the cur­ing process. The top of the forms, or exposed con­crete areas will need to be cov­ered, tem­porar­i­ly, with insu­la­tion to pre­vent the exposed con­crete from freez­ing. Fox Blocks projects can be con­struct­ed any time of the year, no delays for cold weath­er.
How do you control voids in the wall?
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.
What size and how much steel reinforcement is required in an ICF?

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).

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 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
How are Fox Blocks green/environmentally friendly?
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
Is the Fox Blocks ICF product ‘LEED’ rated or certified?
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.
Is the Fox Blocks product rated by ‘Energy Star’?
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.
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.
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.