Walls, Existing Roofs & Hot Roofs

The Path-Performance Wall Assembly, Roof & Hot Roof Reference Library

Here is what’s included with the library:

Wall Assembly Library Document Examples (Click to Enlarge):

Why does anyone actually need this? So they can size their HVAC equipment correctly.

You Cannot Size HVAC Equipment Without This Number.

Every heating and cooling system ever installed was sized with a Manual J load calculation. That calculation needs one number above all others — the true whole-wall and whole-roof U-value of the building. Not the insulation label. Not the code minimum. The actual, verified, layer-by-layer performance of the assembly.

Get that number wrong — or never have it — and everything downstream goes wrong with it. The system gets oversized. An oversized system short-cycles. It never runs long enough to pull the humidity out of the air. Moisture collects in places nobody can see. Mold follows. The equipment wears out in half the time. And the utility bill stays high — not because the furnace failed, but because nobody had the right number before they sized it.

A thermal break does two things here, and both matter. It gives you the real U-value to put into the Manual J. And it lowers the load itself — so the equipment can finally be sized small, and right, and run the way it was designed to. Smaller equipment. Correct dehumidification. No mold. Lower bills for the life of the building. That is the reason. Everything else — the comfort, the quiet, keeping the weather out — comes with it.

Guess it, and the family pays for the mistake every month for 100 years.

The Big Idea

A thermally broken assembly does three jobs at once. It keeps Mother Nature out — the heat, the cold, the moisture, the weather that pounds on a building every hour of every day. It cuts what the building costs to run. And it makes the inside quieter, because the same mass and foam that stop heat also reduce sound. One assembly. Three wins. Most people have never connected them.

Keep Mother Nature out. Keep your money in. Keep the noise outside where it belongs.

Every wall, every ceiling, every roof on your building is in a fight with the weather — every hour of every day, for the entire life of the structure. Heat pushing in. Cold pulling out. Moisture looking for a way through. Noise leaking in from the road. A building built to code fights that battle at the legal minimum, and the family inside pays for the shortfall every month — in utility bills, in comfort, in the sound they can never quite shut out.

A thermal break changes the fight. Done on the inside of an existing wall, sprayed up under an existing roof, or built into a new hot roof, it does what the building should have done from day one: it holds the temperature, it stops the moisture at the right plane, and it quiets the room.

You do not have to tear the house apart to get it. This is how.

The Three Assemblies

1. Interior Thermally Broken Walls

The wall is fighting the weather at every stud. Break the bridge from the inside — warmer, quieter, and you never touch the outside.

Your walls are the biggest surface fighting the weather, and in most existing homes they are losing — a thermal bridge at every stud, conducting heat straight through. A thermal break strip on the inside changes that without touching the siding. Even a half inch, even with the most affordable fill, lifts a typical wall over 25 percent. The best assemblies more than double it. And every one of those fills — cellulose, mineral wool, wood fiber, foam — is also reducing the sound coming through that wall. Warmer. Cheaper to run. Quieter.

2. Existing Roofs — Thermal Break From Below

Your attic is not R-38. It is R-25 on a good day. Fix it from below — up to R-80, no tear-off, and the rain goes quiet overhead.

The roof and ceiling are where most existing buildings bleed the most — a tired layer of settled fiberglass that started at a nominal R-38 and quietly fell to a real R-25 to R-30. Sprayed from below with four inches of closed cell foam to encapsulate the framing, a one-inch gap left so the wood still breathes, and cellulose blown on top, that attic climbs to a true R-60, R-70, or even R-80. No tear-off. No new roof. The framing thermal bridge is gone, the moisture has its escape path, and the rooms below go quiet under the rain.

3. Hot Roofs — Built Right From the Start

A roof is supposed to keep everything out — heat, cold, water, noise. Most barely manage one. This one does all four.

For new construction and vaulted ceilings, the hot roof panel delivers R-60.8 to R-70.8 across the whole roof with a continuous outboard layer that covers every rafter — zero framing penalty, the same R-value at every point. It is the strongest single roof assembly in residential construction. It locks the weather out completely and it does it silently — no thermal bridge, no air leak, no sound path.

The Quiet Angle (the benefit nobody else is selling)

Here is what almost nobody tells you. The same thing that stops heat stops sound. Dense-pack cellulose, mineral wool, wood fiber, sheep’s wool — they are mass, and mass reduces noise. Closed cell foam seals the gaps, and gaps are the number one way sound sneaks into a room. Add the interior strip and the drywall over it, and you have built a quieter house almost by accident.

So when you make a wall or a roof thermally correct, you are also making it calmer. The road noise softens. The rain on the roof becomes a hush instead of a drumming. The neighbor’s mower fades. People pay thousands for soundproofing alone. With a thermal break, the quiet comes free with the comfort and the lower bill.

The same inch that stops the heat stops the noise. Warmer, cheaper, and quiet enough to hear yourself think.

WHAT’S INSIDE:

• 800+ verified wall assemblies — 2x4, 2x6, 2x8, Thermal Break, Tstud, metal stud, and more

• 60 insulation manufacturers covered

• Whole-wall R-values, U-factors, Canadian Metric and EU RSI values

• Parallel-path and whole-wall calculations — so you know what the label says vs. what the wall actually does

• Layer-by-layer breakdowns — every component, every calculation shown

• All 8 North American climate zones

• Material reference tables — air films, lumber, OSB, plywood, cladding, ZIP-R, rigid, semi-rigid, and integrated systems

• Fixed reference assemblies for direct apples-to-apples comparison

• Performance-path compliance support — Passive House, LEED, CSA Step Code, Net Zero

• Video walkthrough — exactly how to read, compare, and apply every assembly

• Free lifetime updates — SIPs, TSUPS, ICF, and emerging assembly types added as they are verified

This is not a code checklist. This is not the minimum. This is the physics behind every wall decision you will ever make.

And Here’s What Comes With It — Free.

Every purchase includes four additional resources at no extra cost:

• The Complete Envelope Playbook & Checklist (~105 pages) — $99 value, yours free. The step-by-step execution framework for new builds, retrofits, and remodels.

• Thermal Suite Deconstruction — A complete breakdown of how a real home achieved a 50% BTU reduction. Real R-values, real U-values, real results. Not a simulation. Copy what already works.

One Number. One Purchase. One Decision That Changes Every Project After This.

Personal Library Member — $299 one time
One individual user. All downloads. All bonuses. Free lifetime updates.

Need more than 10 users? Contact hello@carbonless.org