Door & Window Openings in an ICF Home

Generally, there is little difference in door and window placement in an ICF home when compared to standard wood-framed construction. The biggest thing to keep in mind are openings really close together or really close to corners. Since the supporting structure to the wall is the concrete inside the walls, you need to make sure there is enough in the right places to carry the weight of the rest of the structure.

Door & window openings in an ICF home have two structural elements: post and lintel. The post is the support on either side of the door or window that holds up what is above it. The second supporting structure is the lintel. A lintel is the beam that runs above the window from side to side. A post when combined with a lintel takes the weight above the window or door and distributes it to each side.

When designing your ICF home, make sure you have enough space on each side for strength. If you are putting several small windows together, consider making them one opening and building out the windows inside the larger opening. 

Design Door & Window Openings in an ICF Home

  1. Door & window openings in an ICF home should be spaced not less than 12”. If less than 12”, openings should be mulled or framed as a single opening. If openings must be spaced closer, extra care should be taken to ensure complete consolidation between openings and add additional rebar as needed.
    1. Provide minimum space for adequate consolidation of concrete beside openings. IRC & IBC require internal vibration for all walls.
    2. Mulling smaller openings together may reduce overall vertical rebar beside openings (through eliminating multiple openings). Place rebar as scheduled beside openings (typically 2 bars on each side of opening).
    3. Ensure that proper lintel design is followed for wider openings including stirrups if required.
  2. Openings should be spaced not less than 12” from a corner. If openings are spaced closer, extra care should be taken to ensure complete consolidation in the corner form with additional bracing and strapping. The corner form and buck may try to separate from each other unless braced and strapped properly.
    1. Jambs for garage doors and other large openings should be a minimum of 12”. If narrower, lintel steel should still extend into adjacent walls the required 24” beyond opening on each side.
    2. Use pre-bent steel for wrapping corner lintels. Ensure 40X bar diameter overlap if discontinuous steel is used.
    3. Extra care should be taken to ensure complete consolidation in the jambs. IRC & IBC require internal vibration for all walls.
  3. Doors with side-lights should be framed together unless adequate spacing for concrete is available as noted above.
    1. In applications where full height sidelights are not used, windows should be framed with the door, with ICF wall extending below the window.
    2. Vertical steel should be placed on each side of the opening as scheduled.
    3. Lintel reinforcement should extend 24” beyond the maximum width of the opening.
    4. Additional vertical steel may be placed beside the door, and extend to below the window.