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LevelQuik Advance Coverage Calculator: Bags of Self-Leveler for Wood or Concrete
Enter your floor area and the average pour thickness to see how many 50 lb (22.68 kg) bags of LevelQuik Advance to buy. Custom's coverage chart gives 22–22.7 sq ft per bag at 1/4 inch; the calculator uses the lower 22 sq ft figure and scales it to your thickness, which reproduces the low end of every row in the chart. LevelQuik Advance pours from 1/4 inch to 1 1/2 inches in one lift. The figures come from Custom Building Products TDS-524, published May 5, 2025.
Custom LevelQuik Advance coverage
| Thickness | US | Metric |
|---|---|---|
| 0.25 in (6.4 mm) | 22 sq ft | 2 m² |
| 0.5 in (12.7 mm) | 11 sq ft | 1 m² |
| 1 in (25.4 mm) | 5.5 sq ft | 0.5 m² |
| 1.5 in (38.1 mm) | 3.7 sq ft | 0.3 m² |
Source: Custom Building Products Technical Data Sheet TDS-524: LevelQuik Advance, Published May 5, 2025, read 2026-10-19.
How the calculation works
bags = area × (1 + waste ÷ 100) × thickness ÷ (coverage at reference thickness × reference thickness), rounded up
Self-leveler volume scales with thickness: twice as thick needs twice as many bags. Low spots in the floor add to the real average thickness, so measure the deepest point and the average before you pour.
Worked example
A 150 sq ft floor poured 0.5 in thick with 10% extra: 165 sq ft to cover. One bag covers 22 sq ft at 0.25 in, so at 0.5 in it covers 22 × 0.25 ÷ 0.5 = 11 sq ft. 165 ÷ 11 = 15 bags, so buy 15 (750 lb).
Custom LevelQuik Advance key specs
| Product type | Self-leveling underlayment |
|---|---|
| Bag size | 50 lb (22.68 kg) |
| Mixing water per bag (max) | 5.5 US qt (5.2 L) |
| Thickness range | 0.25–1.5 in |
| Coverage (data sheet) | 22–22.7 sq ft (2–2.1 m²) per 50 lb bag at 1/4" (6.35 mm); 11–11.4 at 1/2", 5.5–5.7 at 1", 3.6–3.7 at 1.5" |
| Mixing water | 5.0–5.5 US qt (4.7–5.2 L) clean, cool water per 50 lb bag |
| Thickness | 1/4" to 1.5" (3.8 cm) in a single pour |
| Reinforcement | fiber-reinforced; no metal lath needed over plywood or OSB |
| Wood subfloor | minimum 3/4" (19 mm) T&G APA-rated Type 1 exterior exposure plywood or OSB equivalent over 16" joists for most finishes; weaker finishes such as natural stone, Saltillo, cement and glass tile may need another plywood layer |
| Priming | all surfaces primed with a Custom primer; all wood subfloors need an undiluted primer coat |
| Install floor covering | non-moisture-sensitive ceramic tile or stone after 4 hours; most other floor coverings after 16 hours |
| Second layer | pour once the first is walkable; re-prime if the first layer has dried more than 12 hours |
| Robinson floor test (ASTM C627) | Extra Heavy on concrete |
| Fire | zero flame spread per ASTM E84 |
| Temperature | ambient, substrate and product between 50°F (10°C) and 90°F (32°C) |
| Use | interior dry areas only; not a wear surface; not for sloped drainage surfaces |
| Item codes | LQA50 (USA), CLQA50 (Canada), 50 lb (22.68 kg) bag |
What LevelQuik Advance is for
LevelQuik Advance is a high-flow, fiber-reinforced self-leveling underlayment from Custom Building Products, the company behind VersaBond, Prism and RedGard. Its selling point is the substrate list: Custom says it can go straight over plywood and OSB subfloors without metal lath, as well as over concrete, existing ceramic tile, cement or epoxy terrazzo, gypsum-based underlayment and wet-scraped cutback adhesive residue. Over wood, Custom positions it as a replacement for cement backerboard under tile.
Floor coverings listed on the data sheet include ceramic, mosaic, quarry and cement-body tile, impervious porcelain and glass tile, natural stone, terrazzo, cement-based precast terrazzo, carpet, wood and parquet, laminate, LVT and LVP, VCT, sheet vinyl and rubber. It is for interior dry areas only. It is not a wear surface, and it should not be poured on slopes that need to drain.
It is not bonded directly to hardwood, lauan plywood, particle board, parquet, cushion-back or sponge-back vinyl, metal, fiberglass or plastic. Custom asks you to contact its technical services for those.
How the calculator works out bags
A 50 lb bag of self-leveler makes a roughly fixed volume of material, so the thickness of the pour decides how far it goes. Custom's TDS-524 chart gives 22 to 22.7 sq ft per bag at 1/4 inch. That is about 0.46 cubic feet of poured material per bag. Double the thickness and the same bag covers half the area: 11 to 11.4 sq ft at 1/2 inch, 5.5 to 5.7 sq ft at 1 inch and 3.6 to 3.7 sq ft at 1 1/2 inches.
The calculator takes your floor area, adds the waste allowance you choose, and divides by the coverage at your thickness. It starts from the low end of the range, 22 sq ft at 1/4 inch, and scales it linearly. That gives 11 sq ft at 1/2 inch, 5.5 at 1 inch and 3.67 at 1 1/2 inches, which sits inside every row of Custom's chart. Bags are always rounded up.
Enter the average thickness, not the deepest point. A floor that is 1/4 inch out at one wall and dead flat at the other averages about 1/8 inch over that span, but LevelQuik Advance has a 1/4 inch minimum, so plan on 1/4 inch as the floor of your estimate. If a room has a few deep dips, split it into zones and run the calculator once per zone, then add the results.
Thickness range
The data sheet gives a single-pour range of 1/4 inch to 1 1/2 inches (3.8 cm). That is a narrower window at the thin end than LevelQuik RS, which Custom rates from featheredge. If your job is mostly a skim coat to remove small humps and dips, LevelQuik RS or another thin-pour leveler will usually use fewer bags than pouring LevelQuik Advance at its minimum.
Over plywood and OSB under tile, Custom notes that the leveler may need to be 1/2 inch thick to take the place of cement backerboard. At 1/2 inch, one bag covers about 11 sq ft, so a typical 5 by 8 foot bathroom floor (40 sq ft) with 10% waste needs 4 bags. Deeper than 1 1/2 inches needs a second layer: pour it once the first is walkable, and re-prime first if the first layer has dried for more than 12 hours.
Wood subfloors: what the data sheet asks for
Plywood must be at least 3/4 inch (19 mm) tongue-and-groove, APA-rated Type 1 exterior exposure plywood or the OSB equivalent, over joists at 16 inches on center, and the floor has to meet the building code for its use, including blocking or bracing. Loose or springy areas must be fixed before pouring. Custom quotes the usual deflection limits of L/360 for porcelain and L/720 for natural stone, and says weaker finishes such as natural stone, Saltillo, cement and glass tile, and some resilient floors, may need an extra plywood layer.
Sanding is acceptable prep; sweeping compounds, chemicals and solvents are not. Block any openings so the leveler cannot run into the next room or down a duct, and fill joints with a patching compound or with LevelQuik Advance mixed at the minimum water level. Every wood subfloor needs a primer coat applied undiluted. Custom also suggests setting heavy dead loads such as stone countertops before the leveler goes down, to reduce the risk of cracks from subfloor creep.
Concrete and other substrates
Concrete must be fully cured, clean, absorbent and sound, with tensile strength above 200 psi and no efflorescence or hydrostatic pressure. Custom's pitch is "just sweep, prime and pour" on acceptable surfaces, with no shot blasting required, but smooth concrete, glazed tile, terrazzo and polished stone may need to be roughened or primed with a bonding primer. For demanding jobs Custom points to mechanical profiling to ICRI CSP 3. Cutback adhesive has to be wet-scraped down to a transparent stain; never sand or grind it, because old adhesive can contain asbestos.
Mixing and timing
Mix the whole 50 lb bag with 5.0 to 5.5 US quarts (4.7 to 5.2 L) of clean, cool water. Add the powder to the water with a heavy-duty 1/2 inch drill and egg-beater paddle at 650 rpm or more, for about 2 minutes until there are no lumps. Overmixing or pumping the mixer up and down traps air, which can shorten working time and leave pinholes. The product can also go through a mixing pump; Custom warns not to overwater.
Pour, spread with a gauge rake to the target depth, then run a smoothing blade over the surface. Keep a wet edge between batches. The ambient, substrate and product temperature should stay between 50°F and 90°F; chill or warm the mixing water to stay in range. Ceramic tile or stone that is not moisture sensitive can be installed after 4 hours, and most other floor coverings after 16 hours, depending on temperature and humidity.
FAQ
How much does a bag of LevelQuik Advance cover?
Custom's TDS-524 coverage chart gives 22 to 22.7 sq ft (2 to 2.1 m²) per 50 lb bag at 1/4 inch, 11 to 11.4 sq ft at 1/2 inch, 5.5 to 5.7 sq ft at 1 inch and 3.6 to 3.7 sq ft at 1 1/2 inches. Custom says the chart is for estimating only and real coverage depends on installation practice and jobsite conditions.
Why does the calculator use 22 sq ft per bag at 1/4 inch?
It is the low end of Custom's range, so it gives the higher bag count, and running short in the middle of a self-leveler pour is the costly mistake. Scaling 22 sq ft linearly gives 11 at 1/2 inch, 5.5 at 1 inch and 3.67 at 1 1/2 inches, all inside the ranges printed on the data sheet.
Can I pour LevelQuik Advance thinner than 1/4 inch?
The data sheet gives a single-pour range of 1/4 inch to 1.5 inches, and its coverage chart starts at 1/4 inch, so the calculator does not go below that. If you only need a skim coat or featheredge, a product rated for thinner pours, such as LevelQuik RS (featheredge to 1.5 inches), is the better fit.
How thick should it be over plywood under tile?
Custom notes that the leveler may need to be 1/2 inch thick to replace cement backerboard under tile. At 1/2 inch one bag covers about 11 sq ft, so a 100 sq ft bathroom needs roughly 10 bags before waste. The plywood must be at least 3/4 inch tongue-and-groove, APA-rated Type 1 exterior exposure, over 16 inch joists, and all wood subfloors need an undiluted primer coat first.
How much water goes in a bag, and when can I tile?
Mix the whole 50 lb (22.68 kg) bag with 5.0 to 5.5 US quarts (4.7 to 5.2 L) of clean, cool water for about 2 minutes with a heavy-duty 1/2 inch drill and egg-beater paddle at 650 rpm or more. Non-moisture-sensitive ceramic tile or stone can go down after 4 hours; most other floor coverings after 16 hours. Cold or humid conditions slow drying.
Custom Building Products and Custom LevelQuik Advance are trademarks of their owner. This page is an independent estimate based on the published data sheet; check the bag label before mixing.