Demolition on a Landed Rebuild: Whose Scope It Is, and Where It Stops
Three builders quote a landed rebuild and the demolition figures are nothing like each other. One is a third of another. The owner's reasonable conclusion is that somebody is expensive and somebody is competitive, and the reasonable conclusion is usually wrong. In most cases the three prices are for three different pieces of work that happen to share a word.
Demolition is not one activity. It is a sequence with a beginning that starts weeks before a machine arrives and an end that is defined by what the next trade needs — and almost every dispute we see about it comes from a disagreement over where that end sits.
What a complete demolition scope actually contains
Before anything is knocked down:
- A condition survey of the neighbours. Cracks that existed before you started are only provable if somebody recorded them, which is the whole argument in why a dilapidation survey belongs before the work.
- Asbestos identification, and removal if it is found. This is not a demolition activity and it is not the demolition contractor's to absorb: asbestos-removal work may only be carried out by a MOM Approved Asbestos-Removal Contractor, and it happens before demolition rather than during it. We set out what that means for an older house in asbestos in an older landed house.
- Disconnection of every service. Electricity, water, gas, telecoms. All of it terminated at source and confirmed, not merely switched off inside the house. A live service discovered mid-demolition stops the site, and it stops it on somebody's account.
- Hoarding, protection and the neighbour arrangements — covered in protecting neighbours during demolition and rebuild.
Then the demolition itself, and then the part that gets left out:
- Debris removal and disposal, which is a haulage and tipping cost driven by volume, not a rounding item.
- Clearing to a level the next trade can work from. This is the line that quotes disagree on.
The gap that costs money: "demolished" is not "ready to build"
A demolition price will very often take the house down to the ground slab and stop. That is a defensible scope. It is also not a site you can start building on.
What remains below that line is the old structure's foundations — footings, stumps, ground beams, possibly piles — plus whatever else was buried when the house was built: the old septic tank on a pre-sewer property, a disused well, a boundary structure with a footing under it, the concrete apron under a driveway. None of it is visible when the quotations are prepared. All of it has to come out, or be worked around by design, before the new foundations go in.
If nobody's scope covers that, it becomes a variation at the worst possible moment: the excavator is on site, the piling crew has a date, and the owner is being asked to approve work with no comparison price available. The way to avoid it is not to negotiate harder. It is to make each quotation say, in writing, what depth and what condition the site will be handed over in.
Attached houses are a different job entirely
Demolishing a detached house is a demolition. Demolishing one half of a semi-detached pair, or a terrace unit with a neighbour on each side, is a controlled dismantling around a wall that has to stay standing and stay weathertight. The party wall becomes the constraint on the method, the machine, the sequence and the programme — see party walls and boundaries on terrace and semi-detached works.
A price built for a detached site, applied to an attached one, is not a bargain. It is a scope that has not been thought about.
Access decides the machine, and the machine decides the price
What can physically get down the road, past the gate and into the site sets the size of the excavator, and the size of the excavator sets how long the work takes and how much of it has to be done by hand. On a narrow road, a plot with no turning space, or a site where the lorry has to reverse a long way, the demolition programme can double without anything about the house changing. This is the same constraint that governs the rest of the build, set out in site access on a landed build.
Any demolition quotation prepared without somebody standing on the road outside is an estimate of a different site.
Should demolition be a separate contract?
Owners sometimes split it out, on the theory that a specialist demolition contractor will be cheaper than a builder's price for the same thing. Occasionally that is true on the headline number. What it does reliably is transfer the sequencing risk to the owner.
The joins are where the money is. If the demolition contractor's scope ends at the slab and the builder's begins at the foundations, the ground between them belongs to nobody. If the demolition finishes two weeks late, the piling crew's date moves and somebody is standing idle. If a buried obstruction is found, there are two parties in the room and no contract that says whose it is. Under a single contract those are the builder's problems. Under two contracts they are yours.
Splitting it can still be the right call — on a straightforward detached site with a clear programme and an owner who is genuinely available to coordinate. It is rarely the right call on an attached house or a constrained site.
When demolition is partial
Not every project takes the whole house down. Retaining part of a structure changes the work completely: temporary support has to be designed rather than improvised, the retained portion must be protected from weather for the duration, and the boundary between old and new becomes a detail somebody has to draw. It also changes what the project is — the point at which extensive works stop being A&A and become reconstruction is a real threshold with real consequences, which we set out in when your project stops being A&A.
Six questions that make three quotations comparable
- To what level is the site being cleared, and in what condition is it handed over?
- Are the existing foundations, stumps and ground beams included, or excluded?
- Who is responsible for buried obstructions found during the works — an old tank, a well, an unrecorded footing?
- Is asbestos identification and removal inside or outside this price?
- Who arranges and confirms the disconnection of every service, and by when?
- Is debris removal and disposal included, and is the volume capped?
Ask all six of every quotation and the numbers will move towards each other. Where a gap remains after that, it is a real difference in price rather than a difference in what was assumed — which is the point made more generally in why builders quote different prices from the same drawings.
The honest summary
Demolition looks like the crude end of a build and is actually one of the most scope-sensitive parts of it. The machine work is a few days. The survey, the asbestos, the disconnections, the protection of the people next door and the removal of what is under the slab are the job — and they are what the cheapest quotation has usually left out, not because anyone is being dishonest, but because nobody wrote down where the work stops.
Wong Lye Pte Ltd is a BCA General Builder Class 2 (GB2) contractor and we build landed houses, so demolition arrives on our sites as the first phase of a build rather than as an isolated job. If you are comparing quotations and cannot tell why they differ, send us what you have and we will tell you what each one has assumed. We work on A&A and reconstruction across Singapore. Message us on WhatsApp.