universal design on the gunpowder: slab pour, rumford fireplace, roof framing

Upon the arrival of the Roxul mineral wool insulation for sub slab, the contractor relaid the Stego vapor barrier (taped to edges at perimeter).  This delay actually may have been a good thing, as the mineral wool was protected from the elements and heavy foot traffic and slab was able to be immediately poured. 
The framing of the second floor and roof are nearing completion.  We are using 2×6 structural walls with 3/4″ plywood sheathing, all edges and corners taped and sealed.  The headers above each opening are two TJIs with Roxul mineral wool sandwiched between them – we have insulated headers!  The lead carpenter did not find it to be time consuming or of any issue, but rather thought it was pretty cool and a no-brainer.
The fireplace is a Rumford fireplace, the most efficient design in providing warmth to a space.