History

The thick bed mortar method has been around for hundreds, if not thousands of years. Historically, a sand

Sand

Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

/cement

Cement

In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...

 mixture was mixed with water to a fairly dry consistency and was spread on either a portland cement

Portland cement

Portland cement is the most common type of cement in general use around the world because it is a basic ingredient of concrete, mortar, stucco and most non-specialty grout...

 water paste (neat cement), or over cement powder spread on the surface which is then sprayed with water to create a slurry coat and spread over the surface. The thick bed mortar would then be compacted and screeded (made flat and/or level) prior to installation of tile or stone. As the slurry coat dried it would bond the mortar bed to the concrete surface on which it was installed. Mortar beds were used underneath almost every tile or stone installation until the late 1950’s when a chemical engineer, Henry M. Rothberg, invented the technology which introduced latex to sand/cement mortar mixes, and created a new industry based on thin bed adhesive

Thinset

Thinset is an adhesive mortar made of cement, fine sand and a water retaining agent such as an alkyl derivative of cellulose. It is usually used to attach tile or stone to surfaces such as cement or concrete....

 installations by founding Laticrete International, Inc.

Laticrete International, Inc.

Laticrete International, Inc. is a family-owned, global manufacturer of products for the installation of tile and stone. Laticrete products are marketed worldwide under the Laticrete, LATAPOXY, and SpectraLOCK brands...

Mortars used in this technique typically have a compressive strength

Compressive strength

Compressive strength is the capacity of a material or structure to withstand axially directed pushing forces. When the limit of compressive strength is reached, materials are crushed. Concrete can be made to have high compressive strength, e.g...

 ranging from at least 400 psi

Pounds per square inch

The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress based on avoirdupois units...

 (2.8 MPa

Pascal (unit)

The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

) to 1600 psi (11 MPa), when tested using ANSI

American National Standards Institute

The American National Standards Institute is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international...

 testing procedures. However, with advancements in technology and materials, the potential strengths of the thick bed mortar system have increased.

Quality controlled manufacturing processes create thick bed mortar mixes which combine carefully graded, high quality aggregates (sand) in a precise ratio with portland cement. This means that a consistent mix can be achieved without the need for a laborer to blend sand/cement and possibly lime at the jobsite. These pre-packaged mortars also eliminate the problems caused by excessively damp sand, incorrect mixing ratios, quality of the raw materials, and piles of sand on a jobsite. Today’s thick bed mortars can be fortified with the inclusion of a liquid latex

Latex

Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...

 or redispersible polymer

Polymer

A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

per the manufacturer’s directions to enhance the performance properties of the thick bed mortar.