A lower total is not automatically better value. Compare the work, materials and finishing included in each proposal first.
Compare the complete intervention
Allow a separate item for making good around the junction. The new wall may be precisely priced while adjustments to existing pointing, mouldings and finishes remain missing.
Align the scope
Use the same headings for preparation, demolition, structure, installations and finishes. Mark missing items and distinguish fixed prices from provisional allowances.
What the drawing needs to explain
Draw a scaled elevation showing existing and new windows together. Resolve the roof-edge, wall and window junction before deciding from an atmosphere image alone.
Which trade-off matters?
Exact reproduction and a clearly contemporary addition are different design choices. Compare their junctions; an almost matching brick or profile can look less coherent than a carefully chosen contrast.
Questions for your own property
- Is the finish level equivalent?
- What is excluded?
- How are changes recorded?
Illustrative design situations, not evidence of completed work. Assess decisions against the actual property.