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Preparation for Thickset Installations per ANSI and TCNA Handbook Methods

Stud Walls

Concrete Slabs

Masonry Walls

1. Mortar bed thickness to be uniform – 1-1/4 in. (32 mm) minimum to 2 in. (51 mm) maximum unless specifier (and manufacturer approves with packaged mixtures). 2. All slabs shall be fully cured, clean, dry, structurally sound, and free of laitance, oily or waxy films, and curing compounds for bonded mortar beds. Refer to manufacturer of packaged mixtures for non-bonded applications incorporating a cleavage membrane. 3. Slope, when required, is to be in the substrate and be designed according to local code requirements. 4. Maximum variation in the slab shall not exceed 1/4 in. in 10 ft. (6 mm in 3 m) from the plane required. 5. Give careful attention to the plans, specification requirements, and locations for expansion joints, control joints, and cold joints designing joint through the mortar bed to the substrate. Required movement joints in the tile layout should align with substrate movement joint.

1. Surfaces must be free of releasing agents or coatings such as oil, wax, paint , block filler, or other bonding inhibitors. etc. anything that would inhibit bonding to the substrate. 2. Poured-in-place concrete should be adequately treated to enable adhesion of the thickset installation. This may include techniques like, but not limited to, bush hammering, sand-blasting, or other surface preparation techniques to enable substrate absorption and adhesion. 3. Maximum variation in the masonry surfaces shall not exceed 1/4 in. in 10 ft. (6 mm in 3 m) from the required plane. 4. Inside and outside corners are to be erected square and free of excess mortar.

1. Maximum variation in the plane of the studs shall not exceed 1/4 in. in 10 ft. (6 mm in 3 m).

2. Metal or wood stud spacing is not to exceed 16 in. (406 mm) on center.

3. Minimum recommended metal stud depth is 3-5/8 in. (92 mm).

4. Metal studs shall be 20 gauge (0.039 in. [0.84 mm]) or greater.

5. Adequate tie back bracing must be provided for stud walls exceeding 8 ft. in height. 6. Inside and outside corners are to be constructed square, level, plumb, and in plane.

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NTCA Reference Manual | 2024 / 2025

Chapter 7 | Thick-Bed Method Installations