Tile & Stone Installation

Southcrete™ 25 Acrylic Mortar Additive (SC25)

Southcrete™ 25 Acrylic Additive is an acrylic additive formulated for use as a direct replacement for water with any non-polymer dry-set mortars, Portland cement grouts, and joint fillers. This product enhances all physical characteristics, such as compressive, shear bond, and flexural strengths. Southcrete 25 is not recommended for use over plastic, metals, or cushion back resilient.

Product Details


  • Premeasured high solids.
  • Improved workability.
  • Excellent bond, tensile, and flexural strengths.
  • Lower water absorption.
  • Interior or exterior use, for both wall and floor.


Southcrete 25 is not recommended over plastic, metals, or cushion back resilient.


Concrete: Floors must be 28 days cured and free of moisture. Floors must be free of any wax, oil, dust or paint overspray. Hence, any further cleaning shall be done using SGM Safe Clean Crystals, refer to Safe Clean label directions. Remove all liquid curing agents. All materials and areas to be tiled should remain above 40°F (forty degrees Fahrenheit) 24-hours prior and 72-hours after installation.

Plywood and Wooden Substrates

  1. All plywood shall be free of dust, oil, and any other foreign matter.
  2. The typical floor or other systems shall consist of joists spaced not over 16″ o.c. and a subfloor of 5/8″ or thicker plywood or 1″ nominal boards.
  3. All floors shall be engineered so that the floors maximum deflection under normal or full load does not exceed 1/360 of span.
  4. A ¼” gap shall be left around all vertical surfaces, also a ¼” gap shall be left between sheets of wood to allow for expansion.



  • Add sufficient Southcrete 25 (approx. 1.75 gallons) to dry mortar to make a trowelable mix. Do not add additional water to mortar or the mix.
  • Stir occasionally during use. In hot weather or on dry concrete, dampening substrate with water will provide longer open time and better adhesion.
  • Apply the mortar liberally with the flat side of the trowel. Use sufficient pressure to work mortar in good contact. Then comb with the notched edge of the trowel to leave uniform ridges.
  • Place tile while the surface is wet and tacky. Spread only as much mortar as can be covered in 15—20 minutes, or before the surface dries.
  • Place tiles with a twisting motion or beat lightly before initial set takes place, to fully embed in the mortar.

NOTE: Mortar that has formed a skin should be re-troweled before applying tile. Use proper sized notched trowel (see diagram) to ensure 100% coverage of mortar to tiles substrate. Some irregular tiles require back-buttering. Follow ANSI 108.5 specifications.


Add either of the following:

  • 2-½ gallons Southcrete 25 Acrylic Mortar Additive to 80 lbs. SGM Floor Mud; or
  • (3:1 sand/cement) gauged with Southcrete 25 additive.

Float to desired thickness with large straight plane.


Add 1-part water to 1-part Acrylic Mortar additive. Excess grout is easy to clean immediately, but extremely difficult to remove when cured. Mortar bed should be allowed to dry thoroughly before grouting. Approximately 48 hours for the thin-bed method, 72 hours for the mortar bed method. If the tile has a high absorption rate, application of a grout release agent is recommended.


Minimum cure is reached in 24 hours, any type of traffic shall be restricted for 72 hours. Setting and drying time may vary according to atmospheric conditions. Grout with SGM blended grout/joint fillers.



  • 1-½ gallon Southcrete 25 acrylic mortar additive to 1 bag (50 lbs / 22.7 kgs) SGM Sanded Thin Set.


  • 2-½ gallon Southcrete 25 acrylic mortar additive to 80 lbs SGM Floor Mud or (3:1 sand cement) gauged with Southcrete 25 acrylic mortar additive.


  • ½-gallon clean water to ½-gallon Southcrete 25 to 50 lbs tile grout/joint filler.


One (1) year from date of manufacture in unopened container.


Meets ANSI A 118.4 when mixed with thin set mortar. Follow ANSI 108.5 requirements for installation.


WARNING — EYE IRRITANT. Product is alkaline on contact with water. Use a paddle for mixing to avoid splashing into eyes or contact with skin. During mixing or application avoid contact with eyes. In case of such contact, flood eyes repeatedly with water and CALL A PHYSICIAN. Wash thoroughly after handling and before smoking or eating. Do not take internally. KEEP OUT OF REACH OF CHILDREN.

  • CONTAINS: Acrylic Polymer Emulsion — C.A.S. 13983-17-0.

SGM, Inc. warrants this product will perform in accordance with its intended use for a period of one (1) year from the date of manufacture. Any claim for defective product must be submitted in writing to SGM, Inc., and samples of defect must be provided. SGM, Inc.’s sole obligation will be to replace any product determined to be defective by SGM Inc. EXCEPT AS PROVIDED HEREIN, SGM, INC. MAKES NO OTHER REPRESENTATION OR WARRANTY OF ANY KIND, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR PARTICULAR PURPOSE. IN NO EVENT SHALL SGM, INC. BE LIABLE FOR DAMAGES OF ANY KIND OR NATURE, WHETHER ARISING BY CONTRACT, TORT OR OTHERWISE. SGM, INC.’S SOLE OBLIGATION WILL BE TO REPLACE ANY PRODUCT DETERMINED BY SGM, INC. TO BE DEFECTIVE.