Inputs
Presets populate stock widths, minima, and notes. Verify with data sheets.
Rounding granularity before choosing stock width.
in
Clear depth of the opening that the membrane must span.
in
Interior leg height at sill backdam or jamb/head return.
in
Face coverage beyond opening onto WRB or facade.
in
Only applied to sill; add a small drip leg if desired.
in
Extra allowance for shingling laps, corners, and stretch.
in
Extra width to accommodate folded corners or preformed pieces.
in
Extra margin added only to the “Safe” recommendation.
Comma-separated inches. Will auto-generate mm options.
Brand Minimums
in
in
in
Minima load from presets and remain editable. Validate against current literature.
Brand Adhesion & Temperature Notes
Select a preset to see indicative adhesion and temperature guidance.
These notes are practical starting points. Always confirm with the latest product data sheet.
Example Data
| Units | Jamb Depth | Interior | Exterior | Sill Down | Overlap | Corner | |
|---|---|---|---|---|---|---|---|
| in | 4.5 | 1 | 2 | 0.5 | 0.5 | 0.5 | |
| in | 5.5 | 1 | 2 | 0.75 | 0.5 | 0.5 | |
| mm | 140 | 25 | 50 | 15 | 15 | 10 |
Results
Sill Width
Tight: -
Safe: -
Next-higher stock for tight and safe recommendations.
Jamb/Head Width
Tight: -
Safe: -
Separate recommendations for jamb/head pieces.
| Element | Tight Requirement & Stock | Safe Requirement & Stock | Slack | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Req (in) | Req (mm) | Stock (in) | Stock (mm) | Req (in) | Req (mm) | Stock (in) | Stock (mm) | Tight (in) | Safe (in) | |
| Sill | - | - | - | - | - | - | - | - | - | - |
| Jamb/Head | - | - | - | - | - | - | - | - | - | - |
Cut‑List Builder
in
in
in
Added to both ends of sill and head pieces.
in
in
| Qty | Piece | Length (in) | Length (mm) | Width Stock (in) | Width Stock (mm) |
|---|
| Stock Width (in) | Total Length (ft) | Estimated Rolls |
|---|
Formula Used
Let D = jamb depth, I = interior upturn,
E = exterior face coverage, S = sill downturn,
O = overlap/creep allowance, and C = corner allowance (if applied). Brand minima: Imin, Emin, Smin.
- Base Sill =
I + D + E + S + O + C - Base Jamb/Head =
I + D + E + O + C - Min Sill =
Imin + D + Emin + Smin + O + C - Min Jamb/Head =
Imin + D + Emin + O + C - Tight = next stock ≥
max(Base, Min) - Safe = next stock ≥
max(Base, Min) + buffer
How to Use
- Select a brand preset or keep Custom and adjust inputs.
- Review minima; leave “Enforce” on for code/spec alignment.
- Click Calculate to get Tight and Safe recommendations.
- Use Copy Shareable URL to save or send the configuration.
- Use the Cut‑List Builder to plan field pieces and roll needs.
FAQs
Tight rounds to the next stock size at brand minima. Safe adds your buffer before rounding, offering extra coverage for field tolerances and irregular substrates.
You can toggle enforcement. Leaving it on helps align with typical instructions; always verify against project specifications and the product data sheet.
Common choices are 0.25–0.75 inches. Larger buffers can help with uneven openings, thick finishes, or aggressive corner folds.
Presets are practical starting points. Always validate against the manufacturer’s current literature for your specific product and climate zone.
If minima are enforced, the calculator raises legs below brand minima before rounding, ensuring coverage targets remain compliant.