Almost every renovation ends up costing more than the number you first pictured. Usually not because the builder got the quote wrong, but because a wall gets opened up and shows you something nobody could see from the outside. A sensible contingency is simply money you set aside up front so the first surprise does not stall the job or send you scrambling for finance. The question is not whether to hold one, but how much.
Here is how we think about it at Prospr Projects: a hedged percentage band rather than a fixed rule, what tends to eat into it, and how a proper scope up front keeps the whole figure smaller and a lot calmer.
What a contingency actually is
Your contingency is a reserve held against the contract value of the work — the agreed figure in your quote. It is not spending money, and it is not a slush fund for nice-to-haves. It sits quietly until something genuinely unforeseen appears, and ideally you hand a good chunk of it back to yourself at the end. Treat it as insurance, not as extra budget.
The important distinction is between the unknown and the undecided. Rot behind a shower nobody could see is a contingency item. Deciding halfway through that you now want underfloor heating is not — that is a change, and it should be quoted and added separately so your reserve stays intact for real surprises. If you want the fuller picture of how a scope becomes a price, read our guide on what a home renovation costs in Cape Town.
How much to hold: a hedged band, not a rule
There is no single correct percentage, and anyone who gives you one confident number is guessing. What matters is matching the buffer to the risk profile of your specific job. Cosmetic work on a sound, modern home carries little hidden risk. Structural work on an older property carries a lot, because you are disturbing things that have been quietly ageing for decades.
As a broad orientation only (mid-2026), the bands below are how the risk tends to sort out. Treat them as a starting point for a conversation with your builder, not as figures to bank on.
| Type of work | Contingency as a share of contract value — broad guide (mid-2026) | Why |
|---|---|---|
| Cosmetic refresh (paint, flooring, fittings, no structural change) | Commonly around 5% to 10% | Little is hidden; surprises are minor |
| Mid-level renovation (kitchen or bathroom re-do, some replumbing or rewiring) | Often lands around 10% to 15% | You open up walls and floors; some unknowns surface |
| Older property or structural work (pre-1980s home, removing walls, roof, foundations) | Frequently 15% to 20%, sometimes more | Age, hidden damage and outdated services drive real risk |
Two things nudge you toward the higher end of any band: the age of the building and how much of it you cannot see until work starts. A 1950s house where the original plaster, wiring and drainage are still in place deserves a fatter buffer than a ten-year-old townhouse. If the scope involves opening up roofs, floors or foundations, budget as if you will find something, because you often do.
What actually eats a contingency
Knowing where the money goes helps you judge your own risk honestly. Four things account for most contingency spend.
Hidden damage found on strip-out
This is the big one, and it is the reason contingencies exist. Once tiles come off and ceilings come down, you see what was really going on: damp behind a wall, rusted pipework, a geyser on its last legs, rot in a timber floor, or wiring that no longer meets a safe standard. None of it was visible when the quote was written, and all of it needs fixing before the pretty work goes back on top. Older homes hold more of these surprises, which is exactly why their buffer runs higher.
Client-driven changes mid-project
Once a space is stripped back and you can stand in it, it is natural to see new possibilities — move a door, widen an opening, add a window. Each is reasonable on its own, but they add up quickly and they are not what your contingency is for. The honest move is to quote every change as it comes up and decide with eyes open, so your reserve stays available for the things you genuinely could not have chosen.
Spec upgrades mid-project
Closely related: standing in the half-finished room, the tile you chose on paper suddenly looks too plain, and the better one is a fair bit more per square metre. Upgraded finishes, taps, and appliances are one of the quietest ways a budget drifts. There is nothing wrong with upgrading — just book it as a deliberate choice against your main budget, not against your safety net.
Supply price moves
Material prices are not fixed forever. Between quoting and buying, the cost of items like timber, steel, tiles, imported fittings or a geyser can shift, and long lead-time items are the most exposed. A good builder locks in prices where they can and flags anything volatile up front, but a modest allowance for movement is sensible, especially on a longer job. Our guide on how long a renovation takes is worth a look, because the longer the timeline, the more room prices have to move.
A thorough scope is the cheapest contingency you can buy
Here is the part most people underestimate: the single best way to hold a smaller contingency is to have a more thorough scope before anyone lifts a tool. Most nasty surprises are not truly unforeseeable — they are things a careful investigation would have flagged.
- Investigate before you finalise. Lifting a floorboard, opening an inspection point, or checking behind a bath at quoting stage turns an expensive mid-project shock into a line item you planned for.
- Pin down finishes early. Choosing your tiles, taps and fittings before the price is agreed removes the biggest source of mid-project drift. A vague allowance for “tiles” is a surprise waiting to happen.
- Get an itemised, fixed scope. An itemised quote shows you exactly what is priced and what is assumed. Where a real unknown exists — say the condition of a hidden drain — a good builder names it as a stated assumption rather than burying it, so you know precisely where your risk sits. It is worth working with a contractor who quotes this way, and we are happy to walk you through exactly how a scope becomes a price.
Money spent on proper investigation up front is not a cost on top of the job. It is money that shrinks your contingency, because every risk you convert from “unknown” to “known and priced” is one you no longer need to hold a buffer against.
When budget is tight: stage the work
Sometimes the honest position is that the full scope plus a proper contingency is more than you can commit to right now. Stretching the budget so thin that there is nothing left for surprises is the riskiest thing you can do, because the first bit of hidden damage then leaves you with a half-finished house and no reserve.
A better answer is usually to stage the work. Break the project into phases that each stand on their own and can be lived with, then complete them as funds allow. A sensible staging order tends to be:
- Do the invisible, structural and services work first — roof, damp, drainage, wiring, plumbing. These are the items that cause the worst surprises, and you do not want to redo finishes later to reach them.
- Then the high-impact rooms — kitchens and bathrooms tend to carry the most weight for both livability and resale, so they are often the next priority. See our cost notes on kitchens and bathrooms.
- Finish with the cosmetic and lower-risk items — paint, flooring in secondary rooms, landscaping — which are easy to defer and carry almost no hidden risk.
Staging lets you hold a real contingency on the phase you are actually doing, rather than a paper-thin buffer stretched across everything at once. If your reason for renovating is income or resale, it is worth being deliberate about which phases add the most value — our guide on the renovations that add the most value can help you sequence sensibly.
A quick note on approvals and compliance
One more thing that belongs in your thinking, if not always in your contingency: not every renovation is a simple like-for-like swap. Structural changes, extensions, or altering the footprint can trigger the need for approved building plans. What applies to your project depends on the specifics, so confirm it with your architect or the City of Cape Town rather than assuming. The same goes for work touching electrics or a solar installation — if solar was added, check that its registration with the municipality was done. Sorting this out up front keeps it from becoming a costly surprise later.
Get an itemised, fixed scope
The tidiest contingency is a modest one, held on a job that has been properly investigated and clearly priced. That only happens when the scope is thorough and itemised before the work starts — when you can see what is fixed, what is assumed, and exactly where your genuine unknowns sit.
That is how we prefer to work. If you would like a clear, itemised scope for your renovation — one that tells you honestly where to hold a buffer and why — talk to us and we will walk your project through with you before a single tile comes off.
