/5 min read/Updated
The Hidden Costs of Building
In short
What a headline rate per square foot leaves out, with figures: professional fees, authority submissions, contingency and GST; demolition, party-wall protection and site clearing; basement shoring; interiors and landscaping; and the cost of living elsewhere for the eighteen months or so the house is a site. The figures are the planning allowances in TMB's own estimating tool, for orientation rather than as quotations. Budgets rarely break on one large surprise; they break on a hundred small decisions taken after the number was set.
In this article
Topics
- Cost
- Planning
- Rebuild
What a rate per square foot does and does not include
Published market ranges are useful for orientation and useless for decisions. Landed rebuilds in Singapore range widely per square foot depending on specification, structure and site conditions, and the spread between the bottom and the top of that range is larger than most people expect.
A rate prices the building. It does not price the people who design it, the authorities who approve it, the house that has to come down first, the neighbour's wall that has to be protected while it does, or the family that has to live somewhere else meanwhile.
The costs that sit outside the rate
The figures below are the allowances our own estimating tool makes, reviewed against the Singapore market in 2026. They are planning numbers for a first budget, not quotations; every one of them moves with the site and the brief.
| Cost | Planning allowance | What moves it |
|---|---|---|
| Professional fees — architect, engineers, quantity surveyor | 8% of construction for a lean team; 12% for a typical full consultancy; 15% for a complex design; 18% for a signature architect with full project management | The size of the team and how much of the project it manages |
| Authority submissions and approvals | About S$30,000 for a standard rebuild; about S$50,000 with a basement or a complex submission | A basement, conservation, queries that need resubmitting |
| Demolition and disposal | About S$10 per square foot of the existing house; S$14 with tight access; S$18 for heavy concrete beside a neighbour | Access, structure, adjoining houses |
| Party-wall protection on a terrace | About S$45,000 for an intermediate terrace; S$30,000 for a corner | How the neighbour's structure is supported through demolition |
| Site clearing and hoarding | About S$8,000; S$25,000 with heavy vegetation or levelling | Trees, slope, what was left behind |
| Basement earth retaining | About S$30 per square foot of basement for sheet piling; S$65 for contiguous bored piles; S$95 for secant piles | Soil, water table, how close the neighbours are |
| Interior fit-out | About S$150,000 for a standard package; S$250,000 enhanced; S$400,000 for a full luxury interior | Carpentry, stone, how much is built in |
| Landscape | About S$15,000 for a basic garden; S$35,000 premium; S$70,000 resort-style | Mature planting, water features, hardscape |
| Contingency | 10% recommended; 15% on a difficult site | What is still unknown, most of it underground |
| GST | 9% | Charged on top of all of the above |
Fees, submissions, contingency and GST compound: contingency is carried on the fees as well as the build, and GST on all of it. At a typical 12 per cent, 10 per cent and 9 per cent, those four alone add roughly a third to the construction cost, before demolition, interiors or anything else in the table is counted.
Living somewhere else
The cost people forget to budget is their own. A rebuild takes the house away for the whole of construction, fit-out and handover, which on a typical programme is around eighteen months of a twenty-one to twenty-eight month project. At S$8,000 a month, the rent our tool assumes until told otherwise, that is about S$148,000; a longer programme or a larger rental takes it well past S$150,000. Storage and two moves come on top.
How Long Does a Landed Home Take to Build? explains what sets the length of that programme.
Utilities and the long-lead items
Disconnecting and reconnecting utilities, and upgrading the power supply for a house that now has a lift, air-conditioning throughout and car charging, are small lines that are easy to leave out entirely.
Long-lead items are the opposite: specification fixed months before installation — stone, imported glazing, a lift — and committed to well before the house looks anywhere near finished. They are in the budget; what catches people is when the money is committed.
Where budgets actually break
Not in one large surprise, but in a hundred small decisions taken after the budget was set. A finish upgraded here, a wall moved there, a piece of joinery added late.
Testing cost against the drawings at D2 and locking it at D4 is the discipline that prevents this. Pattern-matching a live scheme against completed project data flags drift early, which is one of the five places AI sits in our process. How to Read a Cost Plan shows how to tell a budget that will hold from one that will not.
Before the budget, the plot
Most of the costs in the table are set by the site, which means most of them can be known before the plot is bought. A feasibility study prices the site's own risks — the slope, the sewer, the neighbours, the access — while walking away is still an option. If you are considering a plot now, tell us about it.
Key takeaways
- A rate per square foot is orientation, not a budget.
- Fees, submissions, contingency and GST add roughly a third or more to construction cost.
- Demolition, party walls, interiors, landscaping and rent sit outside the rate too.
- Budgets break through accumulated small changes, not single large surprises.
- Cost is tested at D2 and locked at D4, before construction begins.
On this site
First published in the KAPA Journal, written with KAPA Design Collective, the practice that designs and builds our residences.
Published by TMB Development at tmbdevelopment.com/journal/the-hidden-costs-of-building. Quoting a passage with a link back is welcome; republishing it is not — see the terms.
