Lather Skill Trades 1201

Introduction Lathers  Assemble and install the framework for gypsum materials (Drywall & Plaster) in buildings.

Plasters Two main types: 1. Cement based - Used mainly for outdoors. 2. Gypsum based – Indoors only.

Cement Based Can be used indoors for areas that  Are likely to become damp and  Require a greater thickness of cover.

Gypsum Based Used in conjunction with drywall to cover the interior walls. Can be powder form which must be mixed with water, or Premixed and ready for use.

Drywall Joint Compound Two categories: 1. Drying-type compounds 2. Setting-type compounds

Drying Type Compound The most common compound Pre-mixed or Powdered form Dry via water evaporation Allow 24 hours for drying

Drying Type Compound Three kinds of drying type compound: 1. Topping compound: Final thin coat, Ease of workability

Drying Type Compound 2. Taping compound: First coat to capture the joint tape Second coat as filler

Drying Type Compound 3. All-purpose compound: Any stage of drywall joint taping. It is the most commonly used

Setting Type Compound Dries by chemical reaction Hardens much quicker (20 mins to 6 hrs). Harder to sand. Does not come premixed

Drywall  Sheet material made of a sandwich of gypsum and two layers of paper.

Drywall sizes Width  4 feet Length  8, 10 or 12 feet Commercial builders often use sheets up to 16 feet in length.

Drywall Thickness 5/8 inch panel:  Considered fire resistant.

Drywall Thickness 1/2 inch panel:  Most commonly used  General purpose for walls and ceilings.

Drywall Thickness 1/4 - 3/8 inch panel  Used sometimes to overlay existing, older walls in order to make it smoother.  Is also used to make curved walls.

Types of Drywall Standard drywall sheets  Have tapered long edges and the short ends are squared off.  One face is rough, and one face is smooth, for painting and papering.

Types of Drywall Moisture Resistant Board  Also known as Greenboard.  Used in interior areas such as bathrooms and basements where added moisture resistance is needed.

Types of Drywall Fire Rated  5/8 drywall.  Used between apartments.

Fasteners Screws  Type W bugle head screws Has a course thread and provides excellent holding power in wood.

Screws cont’d. Type S bugle head screws  Has a tip that drills its own hole in metal studs in walls.

Fasteners Nails  Ringed-Shank nails The rings provide better grip. Provides 50 to 100 percent greater holding power than a smooth-shank nail.

Drywall Tape Drywall tape is used to cover or seal the joins between drywall edges.

Drywall Tape Types  Flexible Paper The paper tape is applied into wet plaster. Crease in centre so it can be folded.

Drywall Tape Fiberglass Mesh Fabric - The mesh is usually self adhesive.

Drywall Tools

6. Sanders: used to smooth the plaster before paint is applied.

Installing Drywall Drywall is always fastened to the ceiling before the walls. Drywall is fastened to the “studs” of the walls.

Ceiling

Walls