Custom Building Products’ FAQ explains the split: ANSI calls mastics organic adhesives, which bond with a polymer, and thinset mortars inorganic adhesives, which bond with cement. AcrylPro, OmniGrip, LATICRETE’s 15 Premium Mastic and DAP’s Weldwood mastic are all for indoor tile, each with size or water limits. VersaBond and 253 Gold thinsets go indoors and out.
Mastic and thinset, side by side
| Product | Type | Where the maker allows it | Limits |
|---|---|---|---|
| AcrylPro (Custom Building Products) | Pre-mixed acrylic adhesive | Indoor walls and floors; intermittent water such as tub surrounds and shower walls | Floor tile 8 inches or less; not shower floors, steam rooms or underwater; not over waterproofing membranes or radiant heat |
| OmniGrip (Custom Building Products) | Pre-mixed acrylic adhesive | Indoors; tile up to 12 inches; tub surrounds and shower walls | Not shower floors, steam rooms or underwater; not over waterproofing membranes |
| 15 Premium Mastic (LATICRETE) | Pre-mixed latex adhesive | Interior floors and walls | Wall tile up to 10 x 10 inches, floor tile up to 6 x 6; not constant water, steam rooms, commercial showers or over a waterproofing membrane |
| Weldwood Multi-Purpose Ceramic Tile Adhesive (DAP) | Acrylic latex mastic | Interior walls, floors and countertops | No floor tile over 8 x 8 inches and no button-back tile |
| SimpleSet (Custom Building Products) | Pre-mixed thinset | Interior walls and floors; tub surrounds and shower walls | Tile up to 8 x 8 inches recommended; not shower floors, prolonged water or steam; not over waterproofing membranes |
| VersaBond (Custom Building Products) | Powdered polymer-modified thinset | Interior and exterior floors and walls | Not recommended for pools and water features |
| 253 Gold (LATICRETE) | Powdered polymer-fortified thinset | Interior and exterior floors and walls | Not submerged; LATICRETE names 254 Platinum for that |
| Ultraflex 2 (MAPEI) | Powdered polymer-modified thinset | Most interior and exterior residential floors and walls; commercial interior floors and walls, and exterior floors | Not for water immersion such as pools and spas; not for moisture-sensitive stone, agglomerate or resin-backed tiles |
From each product’s technical data sheet.
Where Custom says each one belongs
- Dry walls: Custom’s FAQ calls most ceramic tile adhesives excellent for drywall installations in dry areas.
- Water: it says water affects adhesives far more than thinset mortars, which is why ANSI recommends adhesives for intermittent water exposure and interior use only.
- Floors: it says makers typically recommend adhesives for walls, and thinset mortars are preferred for floors.
- Slow drying: over existing tile, with porcelain, in high humidity, below 60°F or with tile over 6 by 6 inches, it says an adhesive can take far longer than 24 hours to dry, and thinset is preferred.
SimpleSet: thinset in a bucket
Custom calls SimpleSet a pre-mixed thin-set mortar, a no-mix alternative to traditional thinsets. Its sheet cites the same ANSI standard as AcrylPro’s, A136.1 Type I, and carries similar limits: tile up to 8 by 8 inches recommended, no shower floors, and 24 to 72 hours of drying before grouting 8 inch tile.
How long before you grout
- AcrylPro and SimpleSet: a minimum of 24 to 72 hours for 8 by 8 inch tile, per each sheet.
- DAP Weldwood Multi-Purpose: 24 hours on walls and countertops, 24 to 72 hours on floors.
- VersaBond: 24 hours before grouting and light traffic.
- 253 Gold: at least 24 hours at 70°F.
- Ultraflex 2: 16 to 24 hours at 73°F and 50% humidity, varying with jobsite conditions.
AcrylPro’s and SimpleSet’s sheets say they contain petroleum distillates: use them with adequate ventilation, and if swallowed, don’t induce vomiting and call a physician. VersaBond’s sheet warns of Portland cement and free silica dust, and LATICRETE says 253 Gold causes severe skin burns and eye damage.
Tiling over a wood floor?
Thinset on plywood