Field notes
Provisional sums that look calm until the façade arrives
A tidy provisional sum can hide an untidy decision. Pre-tender cost review is where that quiet risk should surface.
Provisional sums exist because some packages are not ready to measure. That is legitimate. What is less legitimate is using a provisional sum as a cushion for an undecided design while presenting the tender total as firm.
Ask what would replace the sum
If the façade system is still in discussion, the provisional sum should say so in language the owner can understand. A round number with no narrative is a future variation wearing a polite label.
Compare the sum with recent local packages
During pre-tender review we compare provisional allowances with recent out-turn costs on similar Taiwanese buildings — not to predict the future precisely, but to spot allowances that are obviously thin.
Adjust the documents, not the hope
If the allowance is light, the remedy is to revise the bill or the contingency — before contractors price the work. Hoping the market will be kind is not a cost strategy.