Retrofit Summary: The existing home, built of single-layer 2×4 timber in 1949, was dismantled and rebuilt to triple-layer 2×6 + 2×4 + 2x4s.   New and re-used studs were staggered to minimize heat transfer from front to back & air gaps were designed between the 2nd and 3rd stud layers.  Slipped between 2nd and 3rd stud rows is a layer of Poly-Iso/Vermiculite boards unbroken by framing.   The original building’s footings and foundation were encased in four inches (4″) of Foamglas rigid insulation, and the cellar slab was removed  and replaced over 4″ of Foamglas and 4″ of Poly-Iso rigid boards.    Stud layers were filled with dense-pack cellulose, while  Vapor-smart Intello paper taped with vapor-smart tape provided the final airtight barrier to the inside before placement of finish gypsum.   Interior floor-to-floor heights are 11′, wet areas are isolated by a Schulter waterproofing membrane.  Rebuilt floors are served by 2-pipe radiant heat, with air conditioning delivered via both zoned fan coils and a central mini-split system.  Exterior insulation (Foamglas) is consistent throughout building.

Existing Home (1949 CMU Block Foundation)

1.   Underpin the existing home
2.   Remove the existing cellar slab
3.   Excavate to create room for rigid insulation + increased finish ceiling height in   cellar
4.   Lay a unbroken layer of Foamglas rigid foam insulation as airtight, watertight,     radon-proof, vermin-proof, and radioactive directly onto a gravel drainage bed.
5.   Wrap existing footings in Foamglas rigid insulation
6.   Install underfloor radiant heating
7.  Pour new concrete slab

An unbroken thermal and airtight barrier is created when under-slab Foamglas insulation comes into direct contact with vertically-laid Foamglas insulation encasing the entire building facade to the insulated roofs.   In addition, building walls are insulated to R-65.

Removing Existing Cellar Slab

Broken concrete was taken out and re-used throughout the construction process.

Cellar floor was taken out piece by piece, with home remaining in place.

A gravel and sand layer was leveled & Foamglas laid to separate slab from the ground.

Example of Foamglas

Foamglas being laid over sand and gravel layer.  Also pictured:  New Durisol below-grade walls meeting existing cinderblock cellar walls, and recycled steel bracing.

View into rebuilt cellar of Foamglas, awaiting new slab pour, Durisol walls, and PolyIso insulation inserted between Durisol and interior stud layer.   Stacks of PolyIso boards see at top-right of photo awaiting installation into wall assembly.