A thick-set installation, also known as a mortar bed or "mud bed," is the traditional and most effective method for installing tile over an uneven subfloor. This method involves creating a new, perfectly flat, and level substrate with a thick layer of mortar (typically 1-1/4" to 2"). Incorporating wire mesh reinforcement within this mortar bed is a critical step. The mesh provides tensile strength, preventing the mortar bed from cracking due to shrinkage or minor substrate movement. This reinforced system creates a highly durable, stable, and monolithic substrate, ensuring the best possible bond and a long-lasting tile installation.

A. Additional grout: Grout is specifically designed to fill the joints between tiles after they are set; it is not a bonding agent or a leveling compound for the subfloor.

B. An extra thick layer of adhesive: This refers to a misuse of thin-set adhesive. Applying thin-set too thickly prevents proper curing, leading to shrinkage, a weak bond, and tile lippage.

C. A mesh substrate with membrane backing: This describes components like uncoupling or waterproofing membranes, which are applied over a prepared substrate, not the method for creating the structural leveling bed itself.

1. Tile Council of North America (TCNA). TCNA Handbook for Ceramic

Glass

and Stone Tile Installation. 2023

Methods F111

F112

F121. These standard methods for thick-bed installations explicitly detail the requirement for "reinforcing wire" or "welded wire reinforcing" embedded within the mortar bed to provide structural integrity

particularly over wood or concrete subfloors.

2. Ballast

David Kent. Interior Construction & Detailing for Designers & Architects. 6th ed.

Wiley

2015. In Chapter 10

"Finish Flooring

" the thick-set method for stone and ceramic tile is described as being "laid on a portland cement mortar bed that is reinforced with wire mesh. This allows the floor to be sloped and creates a true and level surface over which the tile is laid" (p. 338).

3. Simmons

H. Leslie. Olin's Construction: Principles

Materials

and Methods. 9th ed.

Wiley

2011. Chapter 28

"Flooring Materials and Installation

" describes the conventional mortar bed method: "A mortar bed...is reinforced with wire mesh... This method is used where the subfloor is not sufficiently smooth or level for a thin-set application" (p. 914).