Please consider virtue in the accurate and strong build-out of 2x4 to 2x6 thickness in this exterior wall section of my 1955 home in Portland, Oregon. Here is that build-out immediately upon demolition of an outside wall.
I had despised drop-ceiling headers over kitchen cabinets. Such headers are awful heat bleeds in most homes, where at exterior walls they are not accessible for insulation. Too often, none of the headers are filled with insulation. I have the opportunity to expand my kitchen 40% with modest effort where the little kitchen exited to the back yard via a concrete porch fully on-foundation.
It was a crummy little kitchen, and held down the usefulness of the house, beyond being the last room in my house where I had not demolished interior drywall to accomplish data and power wiring improvements, plumbing replacements and tight R15 insulation.
In this one room I would accomplish R22 wall insulation in 2x6 framing.
The improvements are a lot for an individual to accomplish, and are still in progress. For now, share just the details of a 2x4 wall built out to 2x6 with innovation important to progress in existing home energy efficiency and in preservation of well-built homes of the 1950s, defending against demolition.
See my build-out to 2x6 thickness of an existing 2x4 wall. At top place an on-flat 2x4 and 1/2” plywood rip. Stitch on lengths of 5” rips of 1/2” plywood as composite beam webs. Place 2x2s true vertical and flat, leaving 1/2” thermal breaks of both the 2x framing and the webs. The 1/2” gaps behind 2x2s enable simple running of wires, without steel plates to mess up drywall flatness.
Fit 2x6 extensions of the wall bottom plate, and set screws to align the 2x2s flat and vertical. The 1 1/2" raising of nailers for drywall and baseboards, is very useful.
No! There is a better way.
Serious about this in late Summer 2017, I have reset the wall build-out to employ an upright 2x4 at the floor, for better baseboard attachment opportunity, and insulation a bit better.
I will have a much better kitchen, in a home that inspires possibilities with solidly-built homes of the 1950s. Details here are near-final. I do all work except cabinetry fabrication. Completion is expected in Winter 2018. Floor tile will follow some more plumbing and wiring, perhaps insulation. Tile will go even under cabinets and bathroom walls. Watch it all happen, here. Hold our heads up high. Do all we can as individuals to save energy and life for all upon Earth. Stop fracking madness. Stop the oil trains too, now that coal export is dead. Get rid of Trump. Listen to Michael Moore.
While exposed, the built-out framing has been a laboratory of insulation methods, sharing photos in conversation with Insulation Institute . I start out with an exceptional exterior wall judged to be R_total = 5, U = 0.2 not counting added value of wall joists and to-be-added insulation batts. That is with less than half the conductivity and heating cost of common, cheap, non air-tight construction.
Walls built this way are to be treasured and preserved. I'm not sure what should be done with more-ancient walls, hopelessly leaky, hollow, cobweb strewn, with structural defects and dangerous wiring, ruined of insulation value. I suspect though that salvageable homes are determinant not by age, but by investment at time of construction.
Where is the pride of any employee or contractor of the US Department Of Energy paid to support residential energy efficiency, when USDOE Home Energy Scores treat all exterior walls without some insulation stuffing, as of paper, R_total = 0.4, U = 2.5 ? This is insanity that perhaps-deliberately fuels older-home demolition regardless of solid construction. It insanely allows claim that very-huge energy savings can be achieved by a blow-and-go scammer foolishly just adding some partial insulation atop wiring, plumbing and structural messes, if the home is not demolished.
The subjects with Insulation Institute have been layering of batts to kill framing thermal shorts, full batt containment to avoid air circulation, and lack of value where insulation does not fully fill available space. Where are you, NAIMA friend Charles Cottrell, still defending "R13" as the code-call for 2x4 walls?