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The total floor area to be covered with crack isolation membrane.
Measure the tile installation area over the concrete slab where crack isolation protection is needed, typically concentrated over known or suspected slab control joints and cracks.
The area covered by a single roll of membrane, per the manufacturer's specification.
Common rolls are sold to cover roughly 100 sq ft (about 9.3 m²), but sheet-membrane and liquid-applied products vary — check your specific product's coverage rating.
Membrane rolls needed
4 rolls
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Floor Crack Isolation Membrane Coverage Calculator: 4 rolls — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Roll count = ceil(floor area ÷ roll coverage area), the standard method for estimating rolled crack isolation/anti-fracture membrane material
Inputs used
- Floor Area
- 320 sq ft
- Roll coverage area
- 100 sq ft
What this calculation does not cover
- Roll coverage is the roll's face area, not what it covers on the floor. Sheet membranes lap at every seam and turn up at the wall base, and each doorway, column and pipe penetration takes an offcut — a large floor loses several percent of every roll to laps this division never sees, and rounding to the next whole roll only hides that on a small job.
- A membrane is rated to bridge a crack of a stated width in a slab that has stopped moving, and nothing here checks either condition. An active crack from settlement, a slab still giving up its shrinkage, or a joint that opens and closes with the seasons keeps moving under the tile, and it is the product's rating — not its coverage — that decides whether the crack telegraphs through the grout.
- Covering a control joint with membrane is not the same as carrying it through. A joint in the slab still has to reappear as a soft movement joint in the tile above it, filled with sealant rather than grout, and a full-floor membrane under an unbroken field of tile leaves the slab's joint nowhere to go — which is where the tile lifts.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
Part of bigger jobs
This trade is one line of several job takeoffs. Run the whole job and every other trade comes back with it, off the same measurements.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Roll count = ceil(floor area ÷ roll coverage area), the standard method for estimating rolled crack isolation/anti-fracture membrane material
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