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Hilltop Heritage Elementary School

Optimizing Public Education Infrastructure Through Smart Mass Timber Engineering

Hilltop Heritage Elementary School (ES No. 16) in Renton, Washington, establishes a benchmark for high-performance, cost-efficient mass timber execution within public K-12 education. Designed by Hutteball + Oremus Architecture for the Renton School District, the two-story, 7,246-square-meter (approx. 78,000-square-foot) Type III-B facility proves that public school bond budgets can successfully accommodate exposed timber architecture. By strategically deploying hybrid mass timber systems, the project team created a biophilic, light-filled learning environment that functions both as durable civic infrastructure and an active teaching tool for sustainable stewardship.

Strategic Material Placement and Biophilic Learning

To balance structural efficiency with strict public budget requirements, the project team selectively targeted where mass timber would deliver the greatest sensory and functional impact. Acoustic Dowel-Laminated Timber (DLT) supported by glulam beams was integrated into high-volume shared assembly spaces, such as the gymnasium, commons, and library, to provide critical acoustic absorption, robust impact resistance, and biophilic warmth. In the academic wings, exposed Cross-Laminated Timber (CLT) floors and roofs were paired with post-and-beam framing to give classrooms a natural wood finish that enhances student focus, daylight quality, and overall well-being.

Project Highlights

  • Cost-Disciplined Public K-12 Design: Proved that mass timber can meet strict school district budgets without financial compromise by standardizing panel thicknesses and strategically allocating timber systems.
  • Standardized 5-Ply CLT Integration: SmartLam manufactured and supplied the 5-ply stock Cross-Laminated Timber panels, eliminating custom-layup tooling expenses while fulfilling demanding structural and biophilic roles.
  • Cantilever-Driven Frame Optimization: Structural engineers rotated the post-and-beam lines to leverage cantilevered CLT panel ends, significantly shortening backspans and preserving low column and beam piece counts.
  • Architecture as an Educational Tool: Incorporates a custom whole-building carbon storage analysis into the physical environment, translating carbon offsets into visual metrics that serve as an everyday curriculum on regional forestry and environmental science.

Technical Execution

Built under the general contracting leadership of Cornerstone General Contractors, the structural execution centered on clever geometry and standardized product selection. Collaborating with structural engineer Chris Duvall of Coughlin Porter Lundeen, the team eliminated the need for custom, oversized panels by designing strictly within the dimensions of stock 5-ply CLT. SmartLam precision-manufactured the CLT floor and roof panels to exacting tolerances, enabling fast field installation using Simpson Strong-Tie screw assemblies alongside Timberlab glulam framing. By keeping piece counts low and the structural deck profile lean, the team erected the two-story hybrid superstructure rapidly and cleanly, setting a repeatable precedent for regional school districts pursuing sustainable, low-carbon construction.

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