A 4.2 m × 2.8 m timber-frame office on an existing slab, designed end-to-end under UK Permitted Development Class E. Every dimension drives the BOM automatically — change a spec, the quantities recalculate.
Work-from-home primary use, occasional guest sofa-bed, option to add a small WC and underfloor heating later. Three close boundaries, so the design has to stay under the 2.5 m total height limit and well under the 15 m² fire-separation threshold.
| For | Deanna's new house |
|---|---|
| Foundation | existing concrete slab (re-used) |
| Structure | timber stud, breathable membrane, larch cladding |
| Roof | warm-deck flat, EPDM |
| Status | design + BOM done · ordering imminent |
Open it, change the size, and the BOM recalculates. If I can replicate this, you can replicate this.
Plain-English design document. Dimensions, planning rules, material choices, the things that drive every other number.
Live bill of materials. Quantities and prices fed from supplier pages, sortable by trade.
Per-piece cut list ready for the timber yard. Removes the "how many 2.4 m lengths do I need" mental maths.