Project Overview

Timberstone

Award-Winning High-Performance SIP Home by Wren Building Co.

Timberstone is a custom residential project in Washington built by Wren Building Co., showcasing how advanced building systems can elevate both performance and craftsmanship. Designed as a high-performance home with a strong emphasis on durability, comfort, and long-term efficiency, the project reflects an intentional integration of building science and architectural expression.

Structural Insulated Panels (SIPs) were used as a primary building envelope system, forming the foundation of the home’s energy efficiency and construction quality. The project’s performance-driven approach has been recognized through multiple industry honors and certifications.

Design and Sustainability

The Timberstone project was designed with envelope performance as a central strategy. Continuous insulation, airtight construction, and carefully detailed assemblies were prioritized to reduce heating and cooling loads while maintaining consistent indoor comfort.

In Washington’s variable climate, controlling moisture, air movement, and thermal loss is critical. SIP construction supports these goals by delivering a continuous, well-insulated enclosure that reduces reliance on mechanical systems while improving overall energy performance.

Why SIPs?

Structural Insulated Panels (SIPs) were selected to provide a predictable, high-performance enclosure capable of supporting both energy efficiency and architectural design goals. The continuous insulation and airtightness provided by SIPs allowed mechanical systems to be right-sized, improving efficiency, comfort, and long-term reliability.

SIPs also simplified construction sequencing and improved quality control, ensuring consistent envelope performance throughout the home.

Benefits of SIPs

The use of SIPs delivered several key advantages for the Timberstone project:

• Energy Efficiency:
  Continuous insulation and airtight construction significantly reduced heating and cooling loads.

• Interior Comfort:
  Stable indoor temperatures and reduced drafts support year-round comfort.

• Mechanical Optimization:
  Reduced loads allowed HVAC systems to be sized precisely for efficiency and longevity.

• Construction Quality:
  Factory-built panels improved precision and minimized onsite variability.

Performance & Sustainability Features

• Washington Built Green® Certified

• Top Custom Home / Home of the Year, Spokane Home Builders Association

• Featured Home, Spokane Home Builders Association Annual Tour of Homes

• High-performance SIP wall system providing continuous insulation and airtight construction

• ICF basement foundation, delivering continuous insulation, thermal mass, improved airtightness, and moisture control below grade

• Right-sized high-efficiency mechanical systems coordinated with the SIP envelope to reduce energy demand

• Mechanical ventilation strategies, including a high-performance HRV, providing balanced fresh air while preserving energy efficiency in a tight building envelope

• High-performance weather-resistive barriers, flashing systems, and sealed window openings maintaining air-barrier continuity

• LED lighting throughout the home

• Reclaimed beam truss system, reducing material waste while adding architectural character

• Reclaimed custom doors, flooring, and millwork

• Low-VOC paints, tile work, and interior finishes supporting healthier indoor air quality

• Durable material selections focused on long-term performance and reduced maintenance

• Construction practices emphasizing material reuse, quality control, and waste reduction

Construction and Innovation

By combining SIP wall construction with an ICF basement foundation, Timberstone achieves a highly durable, energy-efficient enclosure that performs consistently across seasons. The integration of reclaimed materials further reinforces the project’s commitment to sustainability, craftsmanship, and thoughtful resource use.

This systems-based approach demonstrates how SIPs can support both advanced building performance and architectural excellence.

Challenges and Solutions

Achieving high performance without sacrificing design quality required careful coordination between envelope systems, mechanical strategies, and material selection. SIPs addressed this challenge by delivering a reliable, airtight enclosure that allowed other building systems to perform efficiently without added complexity.

Key Features

• Custom single-family residence in Washington

• Built by Wren Building Co.

• Structural Insulated Panel (SIP) wall construction

• ICF basement foundation

• Washington Built Green® Certified

• Award-winning design and construction

• Durable, energy-efficient, low-maintenance envelope