- Document
- Desktop Feasibility Check — excerpt (Sections 1 & 2 of 6)
- Subject
- Fictional: single-storey rear extension, 1930s semi-detached
- Issued
- Illustrative — no issue date
- Ref
- EX-000 / Rev. 0
Foundation depth vs. neighbouring tree
Drawings show 900mm trench fill. A mature lime sits approximately 6m from the rear corner; on a shrinkable clay this typically drives foundations to 1.8–2.4m with heave precautions. Treat the current depth as unpriced risk until a soil description and NHBC tree table check are done.
Steel beam not carried through to the quote
The plan removes a section of load-bearing spine wall, but the builder's quote contains no steel, padstones, or temporary propping line. Either the quote is incomplete or the design intent has been misread — both end in a variation.
Thermal spec inconsistent between drawing and schedule
Wall build-up notes 100mm PIR; the schedule of works lists 75mm mineral wool. As drawn the wall is unlikely to meet the target U-value without changing the cavity width, which affects the opening dimensions already ordered.
Programme assumes no lead-in on glazing
The 12-week programme starts glazing installation in week 9. Bespoke aluminium sliders commonly run 10–14 weeks from order. Order early or accept a weather-tight delay.