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.

How does the ICF block get secured to the foundation?
The ICF blocks are held in place with either low expan­sion spray foam or a met­al starter track. The bracing/​alignment sys­tem, typ­i­cal­ly installed after the 4th course of block, also sup­ports the ICFs in place. Once the con­crete is in the wall there is no con­cern with the forms mov­ing. The con­crete is con­nect­ed to the foot­ing with rein­forc­ing dow­els.
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.
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.

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.

How do I determine which size ICF to use?

ICFs pro­vide a rein­forced con­crete wall which is designed to spe­cif­ic engi­neer­ing prin­ci­ples. Typ­i­cal res­i­den­tial con­struc­tion, per the applic­a­bil­i­ty lim­its in the build­ing code, allows walls 10′ (3 m) high or less between lat­er­al sup­ports (floor and roof con­nec­tions). Below grade walls must have a min­i­mum 6″ (150 mm) con­crete core. In some regions, an 8″ (200 mm) con­crete core is the min­i­mum allowed thick­ness for below grade walls.

The 4″ (100 mm) form can­not be used below grade as a foun­da­tion wall. The 4″ (100 mm) form may be used for above grade walls up to a max­i­mum of 10′ (3.0 m).

The 6″ (150 mm) form, above grade, is lim­it­ed to approx­i­mate­ly 14′ (4.2 m) in height. Walls high­er than 14′ (4.2 m) must use an 8″ (200 mm) or larg­er form.

Typ­i­cal res­i­den­tial con­struc­tion will use 6″ or 8″ con­crete core size blocks. Project spe­cif­ic engi­neer­ing may allow for some core thick­ness to span ver­ti­cal­ly high­er than these pro­posed guide­lines.