By the MassBid Estimation team · Reviewed by a senior estimator with 10+ years of experience · Published · Updated
In short
To estimate a demolition job, measure every item on the demolition plans: partitions and ceilings and flooring by area, doors, fixtures and equipment by count. Price each with the labor hours to remove it, then calculate the debris volume, add a void factor of about 20 percent for loose material, and divide by the container size to get the number of dumpster loads. Add general requirements, hazardous material work if any, overhead, profit and contingency.
- Selective demolition
- CSI 02 41 19, interior items inside a building that stays
- Structure demolition
- CSI 02 41 16, whole buildings
- Site demolition
- CSI 02 41 13, paving, curbs, utilities
- Debris volume
- Area × thickness ÷ 27, plus about 20% void factor
- Real interior example
- 8,259 sq ft, $46,845 trade cost, $5.67 per sq ft
- Hazardous materials
- Priced separately, from the hazardous materials survey
The three kinds of demolition, and why it matters
Demolition is Division 02 Existing Conditions in CSI MasterFormat, and the three kinds are estimated differently:
| Kind | CSI section | What it is | What drives the cost |
|---|---|---|---|
| Selective (interior) | 02 41 19 | Removing partitions, ceilings, flooring, doors and fixtures from a building that stays | Labor per item, protecting what stays, debris handling through the building |
| Structure | 02 41 16 | Taking down a whole building | Equipment, building volume, disposal tonnage, utilities |
| Site | 02 41 13 | Removing paving, curbs, slabs, utilities and trees | Area and thickness, equipment, haul distance |
Most contractors who ask how to quote a demolition job are pricing selective demolition for a renovation or tenant improvement, so that is the example below.
What you need before you measure
- The demolition plans and keynotes, which say what comes out.
- The new-work plans and reflected ceiling plans. Where new flooring or ceilings are shown, the old ones come out, even when the demolition plan does not say so.
- Mechanical, electrical and plumbing demolition sheets.
- The hazardous materials survey, if there is one. Asbestos and lead change the whole method.
- Wall heights and ceiling types from sections, or a site visit. Demolition plans often leave them out.
- Phasing, working hours and anything that stays occupied.
The demolition takeoff: what to measure and in what unit
| Item | Measured in | Watch for |
|---|---|---|
| Partitions | Square feet of wall (length × height) | Height to the deck or to the ceiling; openings for new doors and storefront |
| Ceilings | Square feet | Tile and grid, drywall or plaster; heights over 12 feet need lifts |
| Flooring and base | Square feet, base in linear feet | Adhesive and mastic removal, tile over tile |
| Doors | Each, with frame and hardware | Size and material, often not on the plans |
| Casework and counters | Linear feet | Base and wall cabinets separately |
| Fixtures and equipment | Each | Plumbing fixtures, appliances, kitchen and specialty equipment |
| MEP removal | Linear feet of duct and pipe, devices each | Make-safe and disconnects by the trades |
| Windows and storefront | Each or square feet | Temporary weather protection |
Debris volume and dumpsters
Each removed item has a volume: area × thickness for partitions, ceilings and flooring, and a size for doors, cabinets and fixtures. Add them up in cubic yards. Broken material sits loosely in a container, so add a void factor; 20 percent is common for interior debris. Divide by the container size and round up.
On the Baltimore job below, the items added up to 68.3 cubic yards in place, 82.0 with the 20 percent void factor and about 34.4 tons. That was five 17-yard loads, carried at $5,400 for dumpsters and hauling.
Demolition debris and dumpster calculator
- Debris in place
- 41.7 cu yd
- Debris loose, with void factor
- 50.0 cu yd
- Container loads
- 3 × 20 cu yd
Volume is area × thickness ÷ 12 ÷ 27. The void factor allows for broken material sitting loosely in a container; 20% is what we used on the Baltimore job below. Haulers charge by weight as well as by load, so check the tonnage limit of the container. Hazardous materials are not included.
A real demolition estimate, line by line
This is a selective demolition estimate we prepared for an 8,259 square foot education building in Baltimore, Maryland. The full pages are on the samples page.
| Item | Quantity | Cost |
|---|---|---|
| Ceiling tile and grid | 6,423 sq ft | $14,130 |
| Flooring with base | 7,595 sq ft | $10,633 |
| Phone booth rooms, complete | 6 each | $5,600 |
| Partitions, including openings for storefront and a plumbing wall | 1,144 sq ft | $3,383 |
| Kitchen island, appliances, countertop and cabinets | 7 items | $1,526 |
| Doors with frames and hardware | 8 each | $1,234 |
| Windows and a drinking fountain | 5 each | $440 |
| Demolition subtotal | $36,945 | |
| General requirements, including $5,400 dumpsters and hauling | $9,900 | |
| Trade cost ($5.67 per sq ft) | $46,845 | |
| Overhead and profit 15%, insurance 3%, contingency 5% | $10,775 | |
| Suggested bid ($6.98 per sq ft) | $57,620 |
Labor was priced per item. Partitions took about 0.08 labor hours per square foot, ceiling tile and grid about 0.055 and flooring about 0.035; a door with its frame took 3 to 4 hours and each phone booth room 20 to 24.
The drawings left several things out, so the estimate stated its assumptions: partitions assumed to run to the deck at 13 feet, door sizes assumed, existing ceilings assumed to be 2 by 2 tile and grid wherever a new ceiling was shown, and existing flooring removed wherever new flooring was shown. Each was marked to verify in the field. A demolition estimate with no assumptions listed usually has hidden ones.
Costs that are easy to miss
- Hazardous materials: asbestos, lead paint and mold are abated under their own sections and often by a licensed specialist. Price them from the survey, or exclude them in writing.
- Disposal by weight: landfills charge by the ton, so concrete, tile and plaster cost more to dump than their volume suggests.
- Protection: dust partitions, floor protection and temporary weather protection for what stays.
- Utility disconnects and make-safe, usually by the electrical and plumbing trades.
- After-hours or phased work in occupied buildings.
- Lifts for high ceilings, and shoring where structure is cut.
- Recycling requirements, and any salvage the owner keeps.
Common demolition estimating mistakes
- Measuring only what the demolition plan tags, and missing what the new-work plans replace.
- Pricing partitions to the ceiling when they run to the deck.
- Leaving out the debris, or the void factor, so the dumpster count comes up short.
- Pricing by volume when the hauler charges by weight.
- Assuming no hazardous materials without a survey.
- Not stating the assumptions, so every unknown becomes a change order dispute.
Getting a demolition estimate done for you
We prepare demolition takeoffs and estimates for demolition contractors, remodelers and general contractors, from tenant spaces to an office-to-apartment conversion of nearly 111,000 square feet, usually in 24 to 48 hours, with debris volume, weight and dumpsters calculated. See demolition estimating or send the drawings for a free quote.
Common questions
Measure every item on the demolition plans, price each with its labor hours, calculate the debris and the number of dumpster loads, add general requirements and any hazardous material work, then overhead, profit and contingency. List your assumptions, such as wall heights and ceiling types, so the quote is clear about what it covers.
It depends on what is removed. On three building jobs we estimated, demolition ran from about $4.47 to $8.31 per square foot before markups, from a tenant space to two office buildings stripped with their MEP systems. The Baltimore education building in this guide was $5.67 in trade cost and $6.98 as a suggested bid.
Area × thickness for partitions, ceilings and flooring, and a volume for each door, cabinet and fixture, added up in cubic yards. Add a void factor, commonly 20 percent, for loose material, then divide by the container size.
Divide the loose debris volume by the container size and round up. On an 8,259 square foot interior demolition, 82 cubic yards of loose debris filled five 17-yard loads.
An allowance for the empty space between broken pieces when debris is loaded. Debris takes more room in a container than it did in place; 20 percent is a common allowance for interior demolition.
Every item to be removed, by unit: partitions in square feet, ceilings and flooring by area, base and casework in linear feet, doors, fixtures and equipment by count, plus the debris volume, weight and dumpster loads.
Division 02 Existing Conditions: 02 41 19 Selective Demolition for interior work, 02 41 16 Structure Demolition for whole buildings and 02 41 13 Selective Site Demolition for paving and site items.
Usually not. Hazardous materials are abated under their own specification sections, often by a licensed specialist, and priced from the hazardous materials survey. A demolition estimate should include or exclude them in writing.