Lather Lathers assemble and install the framework for gypsum materials in buildings. These materials include drywall and plaster.

Plaster and plastering There are quite a few plasters but two main types - gypsum based and cement based. 1. Cement based are used mainly for outdoors. 2. Gypsum based plasters are used indoors only - dampness will attack a gypsum based plaster and cause it to crumble. Cement based plasters can be used indoors for areas that are likely to become damp and areas that require a greater thickness of cover. Gypsum based plaster is used in conjunction with drywall to cover the interior walls of our homes. This plaster can be found as a powder which must be mixed with water, or premixed and ready for use.

What is Drywall? Drywall – sometimes called wallboard, plasterboard, or the brand name Sheetrock – is comprised of a core of wet gypsum rock that is sandwiched between two sheets of heavy paper. When the gypsum core sets and dries, the finished product is rigid and sturdy enough for use as a building material. Drywall is called such because it is a dry alternative to the previously used lath and plaster method of wall construction, where plaster was spread over wood formers while still wet. Drywall is faster, less labour intensive, and cheaper to install than plaster.

Drywall sizes Standard drywall comes in sheets that are four feet wide, with lengths of eight, ten, or twelve feet. Commercial builders often use sheets up to sixteen feet in length. These large sheets make for quicker installations, because they reduce the number of joints (seams) between the sheets that need to be filled and finished.

Panel thickness: 5/8 inch panel- considered fire resistant Panel thickness: 5/8 inch panel- considered fire resistant. Even though drywall generally does not burn, 5/8 inch drywall is used as a firewall. For example, a house that has an adjoining apartment, 5/8 inch drywall must be used on the wall that the two residences share (common wall), and acts as a fire wall. It prevents the fire from spreading from one residence to the other. 1/2 inch panel- most commonly used. General purpose for walls and ceilings.

Panel sizes cont’d 1/4 - 3/8 inch panel- Panel sizes cont’d 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. Drywall is naturally fire resistant, because of the gypsum in the core. When installing in moisture-prone areas such as the walls surrounding bathtubs and showers, it is recommended to use water-resistant drywall, also called "greenboard," or concrete backerboard for further water-resistance.

Types of Drywall Dent resistant -. found in 1/2 inch or 5/8 inch Types of Drywall Dent resistant - found in 1/2 inch or 5/8 inch. Much more durable than regular drywall. Used in high traffic areas, children’s playrooms, garage, etc. Sag resistant- found in 1/2 inch panels. Will not sag like some other 1/2 inch panels. Good to use on ceilings.

Sound control board-. used to reduce sound and also offers higher Sound control board- used to reduce sound and also offers higher thermal insulation. Found in 1/2, 5/8, 3/4 inch panels. Cementious backerboard- cement product reinforced with fiberglass mesh. Used on walls that may be exposed to water, such as showers.

Fasteners Screws 1. Type W bugle head screws - has a course thread and provides excellent holding power in wood. 2. Type S bugle head screws - has a tip that drills its own hole in metal studs in walls. 3. Backerboard screws - made from stainless steel or steel that is non-corrosive

Fasteners cont’d nails - both smooth and ringshank nails are used Fasteners cont’d nails - both smooth and ringshank nails are used. The smooth nails do not hold the drywall as secure as the ringshank nails. The rings on the shank of the nail gets a better grip in the wood, thus decreasing the number of “nail pops” (when the nail starts to come back out of the drywall).

Once the drywall has been secured to the wall studs, the seams or joins are to be covered with plaster before the paint is applied. Before the plaster can be applied to the joins, it must be covered with tape or beads. Tape and beads come in a variety of types: 1. Flexible paper tape: Usually has a seam running along it’s length so that it can be folded to be used in corners. Tends to be more time consuming because it has to be embedded in a coat of plaster.

2. Fiberglass mesh tape: Usually self sticking 2. Fiberglass mesh tape: Usually self sticking. It’s not necessary to apply a coat of plaster underneath it. 3. Composite and metal tapes: Since these tapes are rigid, it makes it much easier to get a straight crisp inside corner. 4. Bullnose and metal corners: These enable you to create a straight and neat outside corner. The metal corner is a 90 degree angle, whereas the bullnose corner is rounded. Plaster must be applied to the edges of both inside and outside corners so that it appears seamless once painted.

Tapes

Common Drywall Tools 1. Utility knife: used for cutting drywall. 2 Common Drywall Tools 1. Utility knife: used for cutting drywall. 2. Drywall Saw: used for making cut-outs in the drywall (circular, rectangular, etc.) 3. Metal snips: use for cutting metal corner beads.

4. Screwgun: used for inserting screws into the drywall and studs 4. Screwgun: used for inserting screws into the drywall and studs. It is different from other power drills because it limits the depth that the screw goes into the drywall. 5. Trowels and taping knives: used to spread the plaster over the drywall joins.

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

7. Water filter system: consists of a vinyl hose connected to a vacuum cleaner on one end and a bucket on the other end with water in it. Another hose leaves the bucket and attaches to a sander. The idea is for the dust from the sander to be vacuumed into t he bucket depositing the plaster dust into the water and not affecting the vacuum.

Installing drywall on ceilings and walls Drywall is always fastened to the ceiling before the walls. This ensures that the drywall that goes on the wall is underneath the ceiling drywall and helps to support the drywall that’s on the ceiling. Drywall is fastened to the “studs” of the walls. Studs are spaced either 16 inches or 24 inches on center. The studs provide the strength for the wall. 16 inch centers 24 inch centers

Ceiling

Walls

Plastering Seams and Joins The following is the sequence of events that is usually followed when plastering a join between two pieces of drywall: 1. If tape is being used, run a coat of plaster on the join.

Plastering Seams and Joins The following is the sequence of events that is usually followed when plastering a join between two pieces of drywall: 1. If tape is being used, run a coat of plaster on the join. 2. Place a piece of tape over the plaster, along the full length of the join.

Plastering Seams and Joins The following is the sequence of events that is usually followed when plastering a join between two pieces of drywall: 1. If tape is being used, run a coat of plaster on the join. 2. Place a piece of tape over the plaster, along the full length of the join. 3. Drag the plaster knife along the tape to allow the excess plaster to squeeze out. Be careful not to tear the tape. Allow to dry.

Plastering Seams and Joins The following is the sequence of events that is usually followed when plastering a join between two pieces of drywall: 1. If tape is being used, run a coat of plaster on the join. 2. Place a piece of tape over the plaster, along the full length of the join. 3. Drag the plaster knife along the tape to allow the excess plaster to squeeze out. Be careful not to tear the tape. Allow to dry. 4. Apply a wider coat of plaster over the tape with a plaster knife. Allow to dry.

Plastering Seams and Joins The following is the sequence of events that is usually followed when plastering a join between two pieces of drywall: 1. If tape is being used, run a coat of plaster on the join. 2. Place a piece of tape over the plaster, along the full length of the join. 3. Drag the plaster knife along the tape to allow the excess plaster to squeeze out. Be careful not to tear the tape. Allow to dry. 4. Apply a wider coat of plaster over the tape with a plaster knife. Allow to dry. 5. Apply a third coat of plaster over the dry coat with a larger plastering knife, feathering the edges (thinning the edges).

Plastering Seams and Joins The following is the sequence of events that is usually followed when plastering a join between two pieces of drywall: 1. If tape is being used, run a coat of plaster on the join. 2. Place a piece of tape over the plaster, along the full length of the join. 3. Drag the plaster knife along the tape to allow the excess plaster to squeeze out. Be careful not to tear the tape. Allow to dry. 4. Apply a wider coat of plaster over the tape with a plaster knife. Allow to dry. 5. Apply a third coat of plaster over the dry coat with a larger plastering knife, feathering the edges (thinning the edges). 6. Sand with fine sandpaper to smooth irregularities in preparation for primer and paint.

Plastering Profile of layers First coat over tape Second coat Third coat Plastering Profile of layers