CLT and CMU Modeling in SketchUp with Lizark

Treat CLT as a panel system

Cross-laminated timber is a mass-timber panel system. It should not be presented as a repeated stud wall or decorative wood flooring. Review panel thickness, boundaries and the intended wall or floor role in the project model.

WoodWorks provides mass-timber technical resources that help frame the design conversation. Panel layout, fabrication, joints, connections and openings need coordination with the project team and supplier. A conceptual panel surface does not settle those details.

Treat CMU as a masonry assembly

Concrete masonry walls introduce block, reinforcement, grout, lintel and bond-beam questions. Use the selected masonry assembly information when describing the model. A solid-looking wall alone does not communicate all of those conditions.

The Concrete Masonry & Hardscapes Association publishes technical resources for masonry design and detailing. Consult the material relevant to the project rather than borrowing wood-framing assumptions for a masonry opening.

Compare systems without mixing their meaning

Apply the relevant US profile before creating each supported option. Profile changes do not convert existing assemblies. Keep CLT, CMU, wood and steel geometry clearly named when comparing space, depth and exterior proportions.

Review openings and floor-to-wall relationships for the selected system. Use sections to show assembly thickness and interfaces. For a client presentation, explain what the model demonstrates and identify the product and structural details that still need the responsible designer’s review.

Worked example: compare continuous systems on one footprint

Use a shared building footprint and floor datum to compare a CLT option with a CMU-based option. Apply the corresponding US profile before creating new geometry and save each option with its system name. Keep wall and roof assumptions explicit. A panel surface and a masonry wall may define similar exterior proportions while requiring different interfaces and opening details.

For the CLT option, inspect panel boundaries, thickness and the relationship to walls or beams. For the CMU option, inspect the masonry reference, opening locations and the concrete floor or roof relationship. A concrete surface generated under a CMU profile should be labeled as concrete; it is not a drawing of individual masonry units or reinforcement.

Use the same section location for both options. Compare clear interior space, assembly depth and transitions at the floor edge. Keep any proposed opening in the same architectural location, then identify the system-specific questions it creates. This gives the client a useful spatial comparison while preserving the distinction between the two construction methods.

Ask different questions for CLT and CMU openings

For CLT, coordinate panel cutting, joints and connection zones with the supplier and project team. A rectangular cut in a conceptual model does not settle fabrication tolerances or the connection detail at its edge. Identify the opening location and intended unit, then make supplier confirmation part of the review.

For CMU, review the opening with the masonry layout, lintel and reinforcement information. A smooth conceptual wall may be appropriate for an early design study, but it should not be presented as a fully detailed masonry assembly. Keep grout, reinforcement and bond-beam requirements in the design documentation rather than inferring them from a solid surface.

Keep the comparison useful as the design develops

Maintain separate model options and note which dimensions have been confirmed by the supplier or structural designer. Include a plan, representative section and exterior view for each system. Link the CLT discussion to the mass-timber references and the CMU discussion to the masonry references below. As details arrive, revise the relevant option and recheck openings and floor interfaces instead of changing both systems as if they were interchangeable.

A practical Lizark workflow

1. Identify whether the option uses CLT panels or CMU masonry.
2. Apply the corresponding US construction profile.
3. Create new supported geometry with reviewed assembly inputs.
4. Inspect openings, thickness and floor-to-wall interfaces.
5. Coordinate supplier and structural details for the chosen system.

What to check in the model

Frequently asked questions