Course outline
Taking off floor prep, moisture testing and demolition
Quantify floor prep as its own lines, not a hopeful per-SF add. Count moisture tests from the test standard (ASTM F2170 and F1869 both call for three tests in the first 1,000 SF plus one per additional 1,000 SF). Estimate patching and grinding by area, self-leveling underlayment by volume at an assumed depth, and demolition by area and existing material. Where the real condition is unknown, price an assumption and offer unit prices for the rest.
By Michael Reddy, IntelBid
After this lesson you can
- Calculate the number of moisture tests a slab requires
- Estimate self-leveling underlayment from area and depth
- Structure prep and demolition as quantities, assumptions and unit prices
The flooring takeoff guide explains why prep and moisture are where flooring bids lose money. This lesson is how to put numbers on them.
How many moisture tests does a slab need?
If the spec puts testing on you, the count comes from the test standard. ASTM F2170 (in-situ relative humidity) and ASTM F1869 (calcium chloride) both call for three tests in the first 1,000 SF, plus one for each additional 1,000 SF. Check the edition the spec references and any additional locations it requires.
- Slab area to receive flooring
- 18,000 SF
- Test method
- ASTM F2170 relative humidity
- First 1,000 SF: 3 tests.
- Remaining area: 18,000 − 1,000 = 17,000 SF → 17 more tests, one per 1,000 SF.
- Total: 3 + 17 = 20 tests.
Patching, grinding and self-leveler
| Prep item | Take off as | Notes |
|---|---|---|
| Crack repair | LF | Only cracks that telegraph or move; check the spec's crack treatment |
| Patching and skim coating | SF | Often an allowance or unit price until the slab is seen |
| Grinding high spots, removing coatings | SF | Curing compounds and sealers may need to come off before adhesive |
| Self-leveling underlayment | SF at an assumed depth → volume → bags | Depth is the big unknown — state it |
| Moisture mitigation system | SF | Frequently priced as an alternate or unit price above a stated reading |
- Area needing leveler
- 3,000 SF
- Assumed average depth
- 1/4 inch
- Yield per bag (example — use the product data)
- 0.45 cu ft
- Waste and overpour allowance
- 10%
- Depth in feet: 0.25 ÷ 12 = 0.0208 ft.
- Volume: 3,000 × 0.0208 = 62.5 cu ft.
- Bags: 62.5 ÷ 0.45 = 138.9 → 139 bags.
- With 10% allowance: 139 × 1.10 = 152.9 → 153 bags, plus primer per the manufacturer.
Removing existing flooring
- Take off removal by area and existing material — carpet, carpet tile, VCT, sheet vinyl and ceramic tile remove at very different speeds.
- Separate adhesive removal — scraping or grinding residue so the new floor bonds is its own operation.
- Count base removal in LF if old base comes out.
- Include disposal — dumpsters, hauling and landfill fees.
- Never assume hazardous material is someone else's scope without saying so. Older flooring and cutback adhesives may contain asbestos; testing and abatement need a clear written exclusion.
When you can't see the slab: assumptions plus unit prices
You often bid prep before the building exists, or before existing flooring is removed. Price a stated assumption in your base bid, and offer unit prices for anything beyond it:
“Base bid includes patching up to 5% of the floor area and self-leveling underlayment at an average of 1/8 inch in areas shown. Additional preparation at $X per SF. Moisture mitigation, if required above the manufacturer's limit, at $Y per SF.”
How to write those assumptions so they hold up is Module 7; how unit prices work is covered in alternates, unit prices and allowances.
How many moisture tests are required per square foot of concrete?
Under ASTM F2170 and ASTM F1869, three tests for the first 1,000 SF and one for each additional 1,000 SF. Always check the edition and any extra locations the project specification requires.
How do you estimate self-leveling underlayment?
Multiply the area by the average depth in feet to get cubic feet, divide by the bag yield from the manufacturer's data, round up, and add a small allowance for waste and overpour. State the depth you assumed.
How should flooring contractors price unknown floor prep?
Include a stated amount of prep in the base bid and offer unit prices per square foot for additional preparation and moisture mitigation, so unknown conditions become measured changes instead of absorbed costs.
Key points
- Moisture test counts come from the standard: 3 for the first 1,000 SF, 1 per 1,000 SF after.
- Self-leveler is volume: area × depth ÷ bag yield — and the depth is an assumption to state.
- Price a written prep assumption plus unit prices for everything beyond it.
Prep as priced lines and standard exclusions
In IntelBid, prep, testing and removal go on the proposal as their own lines with their own units and prices, and your standard prep assumptions and hazardous-material exclusions come from your scope library — so every proposal carries the same protection, not whatever the last one said.
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About the author. Michael Reddy builds IntelBid, bid management software for commercial flooring subcontractors. These lessons come from the bid desk: how the work is priced, won and paid for.