The base SketchUp file of my 9 m × 5 m build is ready; it simply needs the finishing touches so the contractors can work straight from it. Central stringer staircase • Style: modern throughout • Materials locked in: wood treads with a metal stringer and matching metal handrails/balustrades Please model every element to real-world dimensions, showing correct tread height, riser depth, baluster spacing and any fixings that would matter on site. Gabled roof • Shingle cladding, accurate ridge and eave details • Correct thicknesses for rafters, fascia and soffit boards Interior fit-out All remaining furniture and decorative items must be placed exactly where shown in my reference photos and sketches so the scene is construction-ready. Model pieces cleanly (low-poly where possible) but maintain recognisable form for each item. Deliverables - Updated, fully-layered .skp file (latest SketchUp version) - A set of 3–4 exported perspective images that clearly display the stair assembly and roof geometry - One exploded-view scene inside the model to help the builder understand stair components Acceptance criteria 1. Dimensions match my provided plan within ±2 mm. 2. Stair and roof elements are grouped/components, named and placed on tidy layers. 3. No stray geometry, reversed faces or missing textures remain in the file. Files, photos and the current model are ready to send as soon as you confirm.