ARDEX Thinset Calculator
Engineered with German MICROTEC fiber technology. Calculates exact 40 lb ARDEX bags (X 77, X 5, S 28, X 90), 60-minute open times, and water mix ratios.
Select ARDEX Product & Room Area
ARDEX mortars are packaged in 40 lb bags, not 50 lb. Because MICROTEC fibers expand paste volume, you get the exact same coverage with 20% less carrying weight.
Coverage estimates are planning figures calculated under TCNA standards and ANSI specifications. Actual mortar consumption may vary based on substrate flatness, troweling technique, tile back profile, and jobsite environment.
How This Tool Calculates Your Results
Complete mathematical transparency with formulas, standard assumptions, and variable definitions.
ARDEX TDS calculation math:
ARDEX MICROTEC Fiber Matrix Simulator
See how microscopic synthetic fibers absorb horizontal substrate shear stress without snapping.
Microscopic synthetic polymer fibers bridge micro-fissures in the cured paste. When the concrete subfloor flexes thermally, the fibers stretch elastolytically, preventing shear cracks from transferring into the tile.
Official ARDEX Technical Specifications Matrix
Direct data from ARDEX technical data sheets (TDS).
| ARDEX Product | ANSI Standard | Packaging | 1/2" Square Yield | Open Time | Grout Ready |
|---|---|---|---|---|---|
| ARDEX X 77 MICROTEC | ANSI A118.15TE / A118.11 | 40 lb (18 kg) | 38 – 45 sq ft | 60 Minutes | 24 Hours |
| ARDEX X 5 Flexible | ANSI A118.4 / A118.11 | 40 lb (18 kg) | 38 – 45 sq ft | 30 Minutes | 24 Hours |
| ARDEX S 28 Self-Drying | ANSI A118.4F / A118.11 | 40 lb (18 kg) | 35 – 40 sq ft | 20 Minutes | 2 – 4 Hours |
| ARDEX X 90 Outdoor | ANSI A118.15F / A118.11 | 40 lb (18 kg) | 38 – 45 sq ft | 30 Minutes | 2 Hours |
ARDEX Specification Quality Checklist
Ensure complete TDS compliance with ARDEX technical standards.
Common Field ARDEX Projects
80 sq ft (ARDEX S 28)
Requires 3 bags of S 28 Rapid Self-Drying. Consumes 100% water internally to prevent stone warpage.
240 sq ft (ARDEX X 77)
Requires 7 bags of X 77 (40 lb). 60-minute open time allows large layouts without mortar skinning over.
350 sq ft (ARDEX X 90)
Requires 10 bags of X 90 Outdoor. Rapid setting even at 40°F cold weather conditions.
5 Fatal ARDEX Product Installation Mistakes
Forensic breakdown of improper ARDEX mixing and application errors.
Due to MICROTEC fiber density, ARDEX X 77 requires 6.0 to 6.6 quarts of water per 40 lb bag. Using standard thinset water ratios (5.0 qts) makes the mix too stiff, preventing proper rib collapse.
Green serpentine marble contains magnesium minerals that curl when exposed to water. Using standard thinset curls tile edges up by 1/8". Always use ARDEX S 28 Rapid Self-Drying.
ARDEX S 28 starts fast chemical hydration immediately. If you let it slake for 10 minutes like standard mortar, it will flash-set into a concrete block inside the bucket. Mix and spread immediately.
ARDEX polymers bond at the molecular level. Dust or drywall residue acts as a bond breaker. Always vacuum the slab thoroughly and apply ARDEX P 51 primer over porous surfaces.
ARDEX MICROTEC Polymer & Fiber Engineering Manual
Materials science behind MICROTEC fiber reinforcement and self-drying chemical technology.
1. The Science of MICROTEC Fiber Reinforcement
Standard thinset relies entirely on Portland cement crystals and polymer chains to resist shear. When a substrate shifts or flexes, brittle cement crystals fracture suddenly. ARDEX embeds millions of high-tensile microscopic synthetic fibers throughout the mortar paste. These fibers create a multi-dimensional reinforcement mesh that arrests micro-crack propagation, absorbing extreme shear stress and thermal expansion on exterior facades and radiant heated floors.
2. ARDEX Self-Drying Chemical Technology
Standard thinsets require residual water to evaporate through grout joints or into the substrate over 7 to 28 days. In ARDEX S 28, specialized calcium sulfoaluminate (CSA) cements chemically bind 100% of the mixing water into ettringite crystal formations within 2 hours. Because zero free water remains in the bed, moisture cannot penetrate into moisture-sensitive natural stones or agglomerates.
3. 60-Minute Extended Open Time Chemistry
Combing thinset across a large area exposes the ridges to ambient air, causing them to 'skin over' within 20 to 30 minutes under standard mortars. ARDEX X 77 incorporates advanced film-forming cellulose ethers that hold moisture at the ridge surface, maintaining a wet, receptive bed for up to 60 minutes. Installers can spread entire rooms at once before embedding tile.
Frequently Asked Questions
Practical answers backed by TCNA Handbook recommendations and ANSI specifications.