Timber roof trusses in bespoke oak frame garages and solar carports must balance structural load capacity, green oak movement, and the weight of integrated solar panels or battery systems. The truss design is engineered to your site’s specific span, roof pitch, and solar configuration—not standardised—and drawn as a 3D model before any timber is cut.
Why is truss design critical in a bespoke oak frame structure?
A roof truss carries the dead load of the roof itself, live loads from weather and maintenance access, and—in solar carports and garages—the concentrated weight of panels, mounting hardware, and sometimes battery systems. In a bespoke oak frame, the truss cannot be off-the-shelf: it must account for the exact span of your garage or carport, your local wind and snow codes, and the integration points where solar equipment attaches to the frame.
Green oak, the material used in bespoke oak frames, is live timber. It shrinks and moves as it seasons over time. A truss design that ignores this movement can develop checks (radial cracks), misalignment, or stress concentration at joints. The engineer must design trusses that accommodate this behaviour without compromising structural integrity or the visual geometry you expect from a craft-built frame.
What structural factors determine the truss design for your building?
The primary variables are: the clear span (the distance between supports), the roof pitch you want, the total load (roof covering, panels, snow accumulation in your region, and any maintenance traffic), and wind exposure. A garage in a sheltered rural location carries different wind loads than a carport on an exposed hilltop. Similarly, a 6-metre span needs a fundamentally different truss profile than a 9-metre span.
Solar integration adds a second layer of design. Roof-integrated photovoltaic tiles or panel arrays distribute their weight across the truss plane, but they also create thermal movement and potential point loads at mounting feet. A bespoke design takes these loads and anchors them into the truss geometry itself, rather than treating solar as a surface add-on. The 3D model—which you can view and adjust using the studio’s live configurator—shows how each truss member is sized and positioned to handle the total combined load without oversizing timber unnecessarily.
How does green oak movement affect truss joints and connections?
Green oak loses moisture as it dries. Radial shrinkage (from the centre of the log outward) is much greater than tangential shrinkage (around the growth rings). In a hand-cut oak truss, this means a mortice-and-tenon joint at the peak or at a heel connection will move. A design that locks joints rigidly risks splitting the timber or opening gaps as it seasons.
Professional truss design in green oak uses graduated tolerance and slip-fit joinery principles. Mortices are cut with slight clearance; tenons are sometimes left slightly proud so that seasonal shrinkage tightens the fit rather than loosening it. The engineer also specifies timber dimensions that are generous enough to accommodate movement without compromising the structural section modulus. When you receive your 3D model, the drawings show the intended joint clearances and assembly sequence—information your builder will follow during construction.
What role does the 3D model play in truss design approval?
Before any oak is cut, the truss geometry is modelled in 3D. You can rotate, zoom, and configure it using the studio’s live configurator. This allows you to see the actual truss profile, the slope angle, the position of tie beams, collar ties, or struts, and how solar panels or battery boxes will sit on the frame. The model is not a visualization trick—it is the engineering reference. Dimensions, angles, and member sizes are drawn to the specifications required by the structural engineer.
The 3D model serves three purposes: it confirms that the design meets your aesthetic preference (the truss is, after all, often visible inside a garage or carport); it allows the maker to hand-cut each timber member to the exact angle and length required; and it provides the builder with a clear assembly guide. Any changes you request—a shallower pitch, a different span, a repositioned solar mount—update the model, and the engineer re-checks the load path before hand-cutting proceeds.
How do solar panels and battery systems integrate into the truss design?
Solar roof tiles, photovoltaic panels, and battery units add mass and create distinct load patterns. Roof tiles are distributed loads; a wall-mounted or roof-mounted battery is a concentrated point load. The truss must be designed so that mounting points align with timber members strong enough to carry the load without deflection. A bespoke design places principal rafters, collar ties, or purpose-cut blocking exactly where solar equipment fastens, eliminating the need for secondary framing or reinforcement.
In a solar carport, where panels often span the roof as the primary covering, the truss becomes the structural skeleton for the entire photovoltaic array. The design must account for wind uplift (which can be greater on the underside of a panel-covered roof) and thermal expansion of the panels themselves. The hand-cut frame, combined with the 3D model and live configurator, ensures that the carport structure and solar system behave as one integrated load path, not as separate components bolted together afterward.
What questions should you ask when reviewing a truss design proposal?
Ask to see the structural calculations and the load assumptions. Confirm that the design accounts for local wind speed and snow load—requirements differ between regions. Check whether the truss span and pitch match your intended building footprint and roof line. Request clarity on joint details: how is green oak movement accommodated? What tolerances are designed into the mortices and tenons? If solar equipment is part of the design, verify that its weight and location are explicitly included in the load model.
Ask how the 3D model will be delivered and whether you can make changes before hand-cutting begins. Confirm that the drawing set includes assembly notes and that the maker or builder has experience with green oak trusses—not all carpenters are familiar with the tolerances and movement patterns of living timber. Finally, check whether the design is site-specific or generic; a bespoke frame should be engineered for your exact location, not a standard template. The studio’s pricing from £31,485 reflects this bespoke approach: each truss is drawn and cut to order for your building, not manufactured in bulk.