Grip-Rite Stone Wool Knife
The Grip-Rite Stone Wool Knife is a serrated blade purpose-built for Rockwool stone-wool insulation. It rides through dense mineral fiber without compressing the batt, so cuts stay square and cavities pack cleanly to the stud face. Sized right for one-handed use over a scrap plywood or Speed-Square cutting jig — the standard on Rockwool installs and a straight upgrade from a utility knife on stone-wool batts.
- Purpose-Built for Stone Wool: Serrated edge slices dense Rockwool without dragging or compressing the batt like a straight utility blade.
- Clean Complex Trims: Notch around wiring, outlet boxes, plumbing, and blocking without tearing the fiber — essential for tight fill on decoupled walls.
- One-Handed Control: Ergonomic grip and blade length let you cut standing over a plywood jig or Speed Square, keeping cuts square and safe.
- Pairs with Every Rockwool Product: Recommended companion for Safe'N'Sound R11, Comfortbatt R13, and Comfortbatt R15 installs — one knife per crew.
Online orders up to 19 units. For anything larger, call (415) 864-4440 and we'll price the project with you.
Stone Wool Knife Specifications
- Use
- Cutting Rockwool stone-wool insulation batts
- Blade Type
- Serrated, purpose-built for mineral fiber
- Compatibility
- Safe'N'Sound R11, Comfortbatt R13, Comfortbatt R15
- Note
- One knife per crew is standard — additional units for multi-crew jobs
How Stone Wool Knife compares
| Model | Primary Use | Blade Type | Best For | Notes |
|---|---|---|---|---|
| Grip-Rite Stone Wool Knifethis | Cutting Rockwool batts | Serrated, purpose-built | All stone-wool installs | One knife per crew |
| Standard Utility Knife | General trades | Straight snap-off blade | Drywall, boxes, film | Compresses stone wool; ragged cavities |
| Bread / Serrated Kitchen Knife | Improvised cut | Serrated | Emergency only | Not job-site safe; not warrantied |
Applicable Assemblies
See where the Stone Wool Knife fits — from budget baseline to studio-grade isolation.
Best — Drywall + Studs + Insulation + Clips & Channels + MLV + Drywall + Green Glue + Drywall
Tight-packed Rockwool cavities depend on square, clean batt trims — this knife makes them possible.
Better — Drywall + Studs + Insulation + Clips & Channels + Drywall + Green Glue + Drywall
Clean batt trims maintain cavity density around wiring, boxes, and blocking.
Good — Drywall + Studs + Insulation + Clips & Channels + Drywall
Every Rockwool install benefits from a purpose-built serrated blade.
