Birds Hill Rustic is engineered as a hybrid timber frame residence where primary living spaces utilize heavy timber structure while secondary areas incorporate conventional framing. The defining structural elements are two large arcade parallel chord trusses with curved struts spanning the combined great room, dining and kitchen area.
This structural approach allows long-span performance, clear load paths and uninterrupted floor area while maintaining controlled deflection and environmental resilience.
The hybrid configuration optimizes material use by concentrating engineered timber in the central volume and applying conventional framing where span demand is lower.
Arcade Parallel Chord Trusses: Structural Mechanics
The great room volume is supported by two large arcade-style parallel chord trusses. Parallel chord trusses distribute roof load evenly along top and bottom chords connected by web members. The arcade geometry introduces curved struts, which experience combined axial compression and bending forces.
Structural behavior includes:
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Axial compression in rafters
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Tension forces in lower chord members
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Shear transfer through vertical and curved struts
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Load distribution to primary timber posts
Because the trusses span the entire great room, dining and kitchen zone, engineering calculations account for:
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Regional snow load
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Dead load from roof decking and insulation
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Wind uplift and lateral pressure
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Long-term creep deformation
Curved struts require increased member depth to maintain adequate section modulus after shaping. Connection detailing at chord-to-strut interfaces is reinforced to prevent stress concentration.
Deflection limits are controlled to maintain alignment of glazing systems positioned between structural members.
Floor-to-Ceiling Glazing Between Timber Members
Full-height windows positioned between timber posts provide significant daylight and visual openness. Large glazing areas reduce wall shear capacity and introduce concentrated loads at header interfaces.
Engineering measures include:
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Reinforced timber headers above glazing
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Alignment of vertical posts with foundation bearing points
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Shear wall segments strategically placed at structural grid intersections
Differential movement between timber and glazing frames is accommodated through flexible connection detailing.
Because floor-to-ceiling windows increase wind exposure, uplift-rated anchorage at post bases is critical to maintaining structural stability.
River Stone Fireplace and Load Integration
The river stone fireplace introduces significant localized dead load. Masonry weight must be transferred through reinforced floor framing into foundation support.
Engineering considerations include:
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Reinforced joists beneath hearth zone
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Proper anchorage of timber mantle
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Thermal isolation between masonry and timber members
The fireplace mass can contribute to thermal inertia within the living space while remaining structurally independent of primary timber load paths.
Small Loft and Vertical Load Stacking
A small loft is positioned on the entry side within the hybrid structural framework. Loft framing must align with primary posts to ensure direct vertical load transfer.
Structural priorities include:
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Floor joist sizing for residential live load
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Vibration control to maintain occupant comfort
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Guardrail anchorage integrated into timber frame
The loft contributes additional diaphragm stiffness across the upper level, improving lateral resistance.
Timber Species and Finish Protection
Timber elements are finished with Sansin ENS UV Clear Optimum. Transparent UV protection systems must:
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Resist surface degradation from sunlight
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Maintain vapor permeability
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Reduce moisture absorption
End grain sealing is essential to minimize moisture ingress in exposed timber ends.
Moisture content control at installation reduces shrinkage stress and joint movement over time.
Environmental Load Considerations
Birds Hill exposure conditions include:
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Snow load accumulation
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Wind uplift
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Freeze-thaw cycling
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Seasonal humidity variation
Structural countermeasures include:
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Continuous load paths from roof diaphragm to foundation
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Reinforced parallel chord truss connections
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Ventilated roof cavity
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Uplift-rated foundation anchorage
Creep deformation in long-span trusses is incorporated into serviceability calculations to preserve ceiling alignment and glazing performance.
Structural Summary
Birds Hill Rustic demonstrates disciplined heavy timber engineering with:
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Two large arcade parallel chord trusses spanning the primary living volume
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Curved struts engineered for combined axial and bending stress
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Floor-to-ceiling glazing integrated between structural posts
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Hybrid timber and conventional framing alignment
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Reinforced masonry fireplace integration
The project illustrates how long-span timber trusses and large glazing systems can coexist within a structurally coherent framework designed for durability and environmental resilience.
