Most arguments on demolition jobs aren't about the work. They're about something nobody expected, and who pays for it. The way to avoid that fight is to talk about the unknowns before the contract is signed, not after the excavator finds them. That's how we handle every job: we look for what we can, say plainly what we can't see, and agree in advance how anything new will be handled.
Below ground
What can be hiding under the property
Old tanks
Fuel or water tanks from decades ago sometimes turn up when the slab or yard is dug out. They have to be dealt with properly, and sometimes tested, before work continues.
Extra concrete
A slab under the slab, thick old footings, buried patios or debris from a previous demolition. More concrete means more breaking and more truckloads.
A septic system nobody mentioned
Many older South Florida homes were connected to sewer at some point, but the old septic tank may still be in the ground. It has to be abandoned the right way, with its own permit.
Unknown lines
Old water, gas, electric or irrigation lines that aren't on any drawing. Utility locates are called in before digging, but private lines on the property aren't always marked.
Inside the building
What can be hiding in the walls, floors and ceilings
Asbestos
Older flooring, black mastic, ceiling texture, plaster or duct wrap can contain asbestos. If it turns up after work starts, the job stops until it's tested and handled by a licensed abatement contractor.
Unpermitted additions
A converted garage or a back room that was never permitted can complicate the permit, the survey and the scope.
Hidden damage
Termites, rot or water damage that makes a partial demolition bigger than planned, because what was supposed to stay can't.
Things left behind
Furniture, chemicals, paint, tires or an attic full of storage. Anything that isn't part of the building can add hauling and disposal.
Around the job
What can change the schedule, not just the work
Utilities still live
If the electric, gas or water isn't disconnected when the crew arrives, the work waits. Disconnects have their own lead times, and the sewer cap needs a plumber and an inspection.
Permit comments
Reviewers can ask for more documents, a new survey or clarifications. Each round adds time before the permit is issued.
The house next door
A neighbor's wall on the property line, a shared fence or a fragile structure close by can mean more hand work and more protection than expected.
Weather
Heavy rain and storm warnings can stop machine work and hauling. In hurricane season, an open site also has to be secured before a storm.
Planning ahead
How a good contractor plans for the unknowns
Look before quoting
Walk the property, check permit history and property records, and ask the owner what they know about past work, tanks or septic.
Test what can be tested
An asbestos survey before the quote, not after the walls are open, turns the biggest unknown into a known line item.
Write down the assumptions
A clear scope says what's included, what's excluded and what the price assumes, such as one slab of normal thickness and no buried tanks.
Use allowances for what nobody can see
An allowance is a set amount in the contract for a specific unknown. If it isn't needed, it isn't spent. If it's needed, you already agreed on how it's handled.
Put changes in writing first
If something new turns up, the crew stops on that item, documents it with photos, and you get a written change order to approve before the extra work starts.
Comparing quotes
Questions that bring the surprises out before you sign
| Item | Ask | Why it matters |
|---|---|---|
| What does the price assume? | A quote that assumes nothing is buried can look cheaper than one that's honest about what might be | |
| Is the slab and footing removal included? | Some quotes stop at the top of the slab | |
| Who handles asbestos testing? | Testing first avoids a stop-work surprise in the middle of the job | |
| How are unknowns priced? | Allowances or unit prices agreed in advance beat a number made up on the day something is found | |
| How do change orders work? | You want a written change order, approved by you, before any extra work starts | |
| What happens to the schedule? | Ask how a surprise affects the timeline, not just the price |
Two quotes that look far apart often cover different assumptions. The questions above usually explain the difference.
Related
Keep reading
Common questions
Frequently asked questions
What can increase the cost of a demolition after the quote?
The usual causes are hidden conditions: buried tanks or extra concrete, asbestos found behind walls or under flooring, an old septic system, unpermitted additions, more debris than expected, or protection needed for a structure next door. A good contract says how each of these is handled before work starts.
What is an allowance in a demolition contract?
A set amount for a specific unknown, like a possible buried tank or extra concrete. If the condition isn't found, the allowance isn't used. If it is, you've already agreed on how it's handled, so there's no argument in the middle of the job.
What is a change order?
A written agreement to change the scope, price or schedule after the contract is signed. On a demolition job, it should describe what was found, include photos, and be approved by you before the extra work starts.
How can I avoid surprises during demolition?
Share what you know about the property, get an asbestos survey before the quote, ask what the price assumes, and make sure the contract explains how unknowns and changes are handled.
What happens if asbestos is found during demolition?
Work on that area stops. The material is tested, and if it contains asbestos, a licensed abatement contractor removes it before demolition continues. Testing before the job starts avoids this delay.
Can an old septic tank be left in the ground?
Not as it is. An old septic tank has to be properly abandoned, usually pumped out and filled or removed, under its own permit. It's one of the more common surprises on older South Florida lots.
This article is general information. Every property is different, and what's found during demolition depends on the building's history. Talk to your contractor about what your quote assumes and how unknowns are handled before you sign.