Shadowclad Cutting Layout Planner
Optimize your structural cladding. Plan your Shadowclad sheets to maintain groove alignment, minimize expensive H3.2 offcuts, and simplify site installation for AU/NZ builders.
Working with Shadowclad Dimensions
Shadowclad (produced by Carter Holt Harvey) is a dominant force in the Australian and New Zealand residential and commercial building markets. Similar to T-1-11 siding in North America, it acts as both a structural brace and an attractive, weather-resistant exterior cladding.
To accurately plan a panel cutting layout, you must know exactly what stock you are working with. Standard un-grooved and grooved Shadowclad comes in a nominal thickness of 12mm, with two primary sheet sizes:
- Standard Wall: 2440mm × 1220mm
- High Stud Wall: 2745mm × 1220mm
When inputting these into your optimizer, remember that the shiplap edge profile means the effective coverage width is closer to 1200mm. If your wall is 6000mm long, you cannot simply divide by 1220mm—you must divide by 1200mm to accurately calculate the number of sheets required to span the distance.
Optimizing for Grooves (150mm & 200mm OC)
The most distinctive feature of Shadowclad is its routed grooves, available in either 150mm or 200mm "on center" (OC) spacing. This aesthetic feature creates a massive challenge for builders trying to reduce waste: you cannot simply rotate pieces arbitrarily to fit them on a sheet.
If you cut a rectangular panel out of a sheet and try to rotate it 90 degrees to fit it tightly next to another part, the grooves will run horizontally instead of vertically. Even worse, if you flip a piece 180 degrees but don't align the cut precisely, the grooves on the joined pieces will stagger rather than flowing seamlessly down the wall.
CutWize "Grooved" Grain Mode
CutWize includes a specialized grain direction setting designed specifically for materials like Shadowclad and T-1-11. When configuring your sheet cutting optimizer cutting plan:
- Locks parts to vertical orientation only
- Prevents 90-degree offcut rotations
- Ensures vertical aesthetic continuity
NZ Building Code & Installation Constraints
When planning your cutting layouts, compliance with the NZ Building Code (E2/AS1) or the NCC in Australia dictates how your cuts must be oriented and treated.
Vertical vs Horizontal: Grooved Shadowclad is engineered to be installed vertically. The grooves act as micro-channels for water shedding. While it is technically possible to install it horizontally in specific architecturally designed applications (usually involving a rigid air barrier and drained cavity), the vast majority of applications require vertical installation to pass inspection.
H3.2 Treatment Edges: Shadowclad used for exterior cladding is H3.2 LOSP treated to resist fungal decay. The factory edges are fully saturated. Whenever you generate a cut on site—whether ripping a sheet to width or cutting out a window opening—you expose the untreated inner core of the plywood. Every single cut edge mapped out in your optimization plan must be brushed with an appropriate timber preservative before installation.
Reducing Waste on Gable Ends and Rakes
Cladding waste skyrockets when you hit the roofline. Gables and raked ceilings require large, angled cuts that leave behind massive, oddly-shaped offcuts.
Instead of throwing these H3.2 treated offcuts in the skip, a smart layout planner utilizes them. The triangular offcut from the left side of a gable can often be used on the right side of the house. However, because of the grooved face, you cannot simply flip the board backwards (exposing the flat back). You must keep the face outward and slide the piece horizontally or vertically to the matching pitch.
By inputting the exact dimensions of your gable cuts into the CutWize cut list optimizer, the software will automatically nest these tricky angled shapes alongside your standard square window cutouts, dramatically reducing the total number of expensive 2745mm sheets you need to order.
Frequently Asked Questions
Stop Guessing Your Cladding Orders
Map out your Shadowclad walls, lock in your groove orientation, and let CutWize generate the perfect cutting map to save you time on site.
Related Tools: Sheet Optimizer | Plywood Calculator | T-1-11 Calculator
Related Guides: Nesting Grooved Sheets | Reduce Plywood Waste | T-1-11 vs Shadowclad | Cutting Grooved Panels