Recommended test
Generate a full Mansard, inspect its end framing and run a separate assembly check if the service is enabled.
- Choose Mansard in Build's truss dialog and switch Roof ends to Hipped ends — full Mansard.
- Confirm Manual is active and Automatic is unavailable; inspect the inherited geometry and CC.
- Generate, hide roof layers and check paired girders, step-down caps, hip/jack contacts and beveled end joists.
- In the truss dialog, expand Experimental whole-roof analysis, review direct service loads and analyse the assembly.
- Inspect reactions and displacement, download the result and confirm that no section sizes are changed.
Select hipped ends
Open Build > Gable > Roof Structure > Truss > Mansard, then choose Hipped ends — full Mansard. The roof has four steep lower faces and four shallow upper faces. The end choice belongs to the building, so it is separate from a saved standalone truss cross-section.
This option currently uses Manual concept framing. Automatic is unavailable: one passing gable-ended truss calculation cannot approve the whole spatial assembly.
The initial scope is a rectangular single-storey building, 2–12 m wide, at least as long as it is wide and no longer than 18 m. CC is 200–1200 mm and overhang 0–600 mm. Upper pitch is 12–50°, lower pitch 45–80°, with the lower pitch more than 5° steeper. These are supported geometry limits, not capacity ratings. Dormers, porches, upper storeys and edited framing are excluded.
Inspect the framing and layers
The generated layout includes set-back two-ply girders, step-down trusses, eight backed hip rafters, slope-following jacks, fitted bearing blocks and end ceiling joists. Ordinary timber uses the selected section thickness; girders have two separate plies and hips are double width. The ply count is a Manual layout assumption, not a calculated capacity.
End ceiling joists bevel to meet the jack rafters. Longitudinal infill meets chord faces and fits around intervening hip/jack timber. The selected CC remains the maximum spacing, with extra boundary members where needed.
Roof sheathing, battens, covering, hip/ridge caps, break flashing, fascia, gutters and optional soffits follow the eight faces. There are no gable skins or bargeboards. Roof Live Control adjusts generated covering thickness, offset and appearance across the faces. Regenerate to change the roof type or framing layout.
Experimental whole-roof analysis
Expand Experimental whole-roof analysis in the truss dialog and select an available Cloud service or pair the Windows local calculation engine. It sends a separate 3D beam-and-joint model to Code_Aster and reports elastic displacement and support reactions.
These inputs are direct service loads, unlike Automatic truss sizing’s ground-snow input:
| Input | Area used |
|---|---|
| Roof dead load | Actual sloping roof area |
| Vertical roof action | Horizontal roof plan area |
| Total attic floor load | Central floor area |
Timber self-weight is added. The result includes separate dead, roof and floor cases plus their combined case. Download the result with its inputs. Changing the draft or closing the dialog invalidates the transient result. It never changes member sizes or unlocks Automatic.
The model assumes rigid offset joints, equal sharing between girder plies and continuous bearing along all four outside wall lines. It does not infer support interruptions from doors or windows. Reactions still need to be carried through actual headers, studs, plates, floors and foundations.
Use the result as an experiment
Neither a small displacement nor a positive reaction proves capacity. The experiment does not establish connection design, bracing/diaphragm capacity, wind, snow drift at the breaks, Norwegian load combinations or complete Eurocode compliance. It is a read-only elastic response of the stated model.
Regenerate an existing full Mansard to obtain the latest joint fitting. Saved projects keep their existing solids until regenerated; preserve a copy before replacing manually edited geometry.