The Mistake: Underestimating Refurbishment Costs (The Builder's Quote Trap)
New investors routinely underestimate build costs by 20–40%. Optimistic builder quotes, scope creep, and unforeseen structural issues are the three most common budget killers on a refurbishment project.
The single most common cause of failed property development projects is running out of money mid-build. And the root cause is almost always an optimistic initial budget. Builders quote for the scope they are given — they cannot price what they haven't been asked to quote, and they rarely flag issues they haven't yet uncovered.
A robust refurbishment budget includes: the builder's quote, plus a minimum 15–20% contingency for unforeseen works (hidden damp, outdated wiring, asbestos, structural movement), plus professional fees (architect, structural engineer, building inspector), plus finance costs for the build period, plus your own time. On a major refurbishment, the final cost routinely exceeds the initial quote by 25–35%. Lenders know this — which is why development finance draws down in arrears, not upfront.