Adhesive Calculator
How It Works
The right amount of adhesive ensures a strong, lasting bond for tile, flooring, and other surface installations. Coverage depends on three main factors: the total area, the trowel notch size (which determines how much adhesive is applied), and the adhesive type.
Trowel size is critical — larger notches deposit more adhesive for larger or uneven tiles. A 1/4 x 1/4 inch notch is standard for small tiles and smooth surfaces. A 1/4 x 3/8 inch notch works for medium tiles (8-12 inches). A 1/2 x 1/2 inch notch is needed for large format tiles and uneven substrates.
Thin-set mortar is sold in 50-lb bags and mixed with water. Mastic (pre-mixed adhesive) is sold by the gallon and is easier to use but not suitable for wet areas. Floor adhesive is designed specifically for vinyl, carpet, and engineered wood installations.
Frequently Asked Questions
How much thin-set do I need per square foot?
With a 1/4 x 3/8 inch notch trowel, a 50-lb bag of thin-set covers approximately 75-100 sq ft. Larger trowel sizes reduce coverage. Always back-butter large format tiles in addition to troweling the substrate.
What trowel size should I use?
Small tiles (up to 6"): 1/4 x 1/4 inch. Medium tiles (6-12"): 1/4 x 3/8 inch. Large tiles (12"+): 1/2 x 1/2 inch. For large-format tiles, you want 95% or greater adhesive coverage on the tile back.
Thin-set vs mastic — which should I use?
Thin-set mortar is stronger, waterproof, and suitable for floors, showers, and exterior use. Mastic is easier to apply, sets faster, and works well for dry-area wall tiles. Never use mastic in wet areas or on floors.
How long does tile adhesive take to set?
Modified thin-set: 16-24 hours before grouting. Unmodified thin-set: 24 hours. Mastic: 24 hours for light traffic, 48 hours for grouting. Full cure for thin-set is 28 days.