Layers and materials
Add materials from the library, set each layer's thickness, fill stud bays, and put the layers in order from outside to inside.
An assembly is a stack of layers. The first layer is the outside face, the last is the inside face. Each layer gets a letter on the drawing and in the list: A is the outermost.
The material library #
The library on the left groups the built-in materials:
- Structure & Framing: wood and steel framing, CMU, cast concrete.
- Insulation & Air: batts, rigid boards, mineral wool board, the WRB / air barrier, vapor retarders and the air gap.
- Cladding, Sheathing & Finishes: brick, siding, metal panel, sheathing and gypsum board.
Each item shows its R per inch and what it counts as: continuous, cavity, insulatable (framing that can hold insulation in its bays), or sheet, no thickness. Type in Search materials… to filter the list.
Add a layer #
Click a material in the library. It's added at the interior end of the stack and selected, so you can set its thickness right away.
Framing arrives with its stud bay already insulated, using the labeled batt that fits its depth. If you add a separate batt layer while a framing layer is already insulated, the tool warns you: the batt would be counted twice. Use one or the other.
Set the thickness #
In the layer's row, pick a common size from the list, or type any thickness in inches in the box next to it.
Sheet goods (the WRB, poly vapor barrier and smart vapor retarder) have no thickness. They show sheet good — no thickness and are drawn as a line.
Fill the stud bays #
Wood and steel framing rows have a cavity fill list:
- Empty bay
- fiberglass batt, mineral wool batt, cellulose, open-cell spray foam or closed-cell spray foam
For batts, pick the product's labeled R-value (R-13, R-19 and so on). For sprayed fills, type the rated R from the product's data sheet; it starts at a typical value for the depth. Then pick the stud spacing: 16″ o.c. or 24″ o.c.
The code check counts the labeled R of the product, not R per inch times depth. When you change a framing layer's depth, a sprayed fill follows the new depth, and an untouched default batt switches to the batt that fits.
The vapor control layer #
Click VCL on a layer to mark it as the assembly's vapor control layer. Click it again to clear it. It's drawn on the section, and the dew point check judges where it sits. See Dew point and vapor.
Reorder or remove layers #
At the end of each row:
- ↑ moves the layer toward the exterior.
- ↓ moves it toward the interior.
- × removes it.
Click a row, or the layer in the drawing, to select it. The selected layer is highlighted in both places.
What each row shows #
On the right of each row are the layer's R-value and its vapor permeance in perms. Hover over them for the cavity R, the perms and the vapor retarder class.
Wall or floor #
Wall / Floor in the toolbar sets which code rows apply. The layers work the same way for both.