Acceptable Variations

  • Foundation & Floor Assembly

    Pier & Beam

    Pro

    • Easily accommodates sloped sites with minimal earthwork. 
    • Minimizes foundations (efficient material use). 
    • Physical and visual separation from ground provides easier barrier from termites and water infiltration. 
    • Provides access to plumbing pipes, etc. under floor. 

    Con

    • Must protect the underside of the floor. 
    • More difficult to create an accessible entrance. 
    • Difficult to meet FORTIFIED standard. 

    Crawlspace

    Pro

    • Accommodates sloped sites with less earthwork required. 
    • Physical separation from ground provides easier barrier from termites and water infiltration. 
    • Provides access to plumbing pipes, etc. under floor. 

    Con

    • More difficult to create an accessible entrance. 
    • Barrier between ground and building envelope is thin; easy to damage.

    Elevated Slab

    Pro

    • Physical separation from ground provides easier barrier from termites and water infiltration. 
    • Accommodates accessible entrance (close to ground). 

    Con

    • More earthwork required to prepare foundation. 
    • On sloped sites, requires a large amount of gravel fill. 
    • Does not provide access to plumbing pipes, etc. under floor. 

    Slab-on-Grade

    Pro

    • Easily accommodates accessible entrance (close to ground). 

    Con

    • More earthwork required to prepare foundation, especially on sloped sites. 
    • More difficult to protect house from termites and water infiltration. 
    • Does not provide access to plumbing pipes, etc. under floor.
  • Wall Assembly

    Cavity Insulation Only

    Pro

    • Less layers (components) to install. 
    • More positive contact between exterior cladding and wood subsurface, as opposed to houses with continuous XPS insulation. 
    • Simplifies detailing around windows and doors. 

    Con

    • Lower R-value. 
    • Studs act as thermal bridges between through the thermal envelope.

    Cavity Insulation + Continuous Insulation

    Pro

    • Continuous insulation provides thermal break between the exterior environment and the wall studs. 
    • Higher R-value. 

    Con

    • Detailing around windows and doors can be more complex; cladding must return beyond continuous insulation. 
    • (XPS) More difficult to ensure that cladding is fastened to sheathing/studs. 
    • (Zip R-Sheathing) Unit price may be high, and product may need to be special ordered. 
  • Ceiling & Roof Assembly

    Trusses w/ Solid Deck, Insulation @ Ceiling Plane 

    Pro

    • Less conditioned area (only heat & cool the living spaces). 
    • Meets FORTIFIED standards. 

    Con

    • Any ductwork placed in attic will be outside the thermal envelope. 
    • More difficult to mitigate penetrations in air barrier at ceiling (at lights, bath fan, ERV, etc.). 

    Trusses w/ Solid Deck, Insulation @ Roof Plane 

    Pro

    • Provides space for ductwork within the thermal envelope. 
    • No need to seal penetrations in ceiling plane (electrical, plumbing pipes, ductwork, etc). 
    • Meets FORTIFIED standards. 

    Con

    • More conditioned area (heating/cooling attic as well as living spaces).