Interior Wall and Ceiling Finish

Interior finishing

Definition: The installation of

cover materials to walls and ceilings

Prerequisites to Construction: Utilities, heating,

and insulation are installed

Exterior doors and windows must be hung and installed.

Interior walls can be covered with any one of a number of materials:

Gypsum wallboard(drywall)

Plywood and particleboard

Plaster

Gypsum wallboard for plaster veneering

Hardboard and fiberboard

Cement board

Predecorate gypsum paneling

Solid wood paneling

Special finishes

Gypsum wallboard (drywall)

Def: A laminated material

with a gypsum core and paper covering on either side.

Has fireproof core Variety of thickness, shown on right, and lengths (4’ x 8’, 7’, 9’, 10’, 12’, and 14’ Also requires special tools (next slide):

Gypsum wallboard for plaster veneering

This is a base of gypsum board

Usually ½” thick

It’s applied as a backing for a thin coat of plaster

Predecorated gypsum paneling

This is the same as gypsum wallboard. The difference: Decorative vinyl

finishes have been applied and edges have received special treatment so no other finish work is needed.

Plywood and particleboard

Picture to the right is fabricated in 4’ widths. Lengths: 7, 8, 9, and 10’ Prefinished in a variety of colors and patterns

Hardboard and fiberboard

These are produced from wood fibers in sizes and thicknesses similar to plywood. The face finish is simulated to look like wood. Variations of fiber board are used as ceiling coverings.

Solid wood paneling

These are boards or pieces of solid wood. Widths: Vary from 2 to 12” Thicknesses: Either 1” or 2” Lengths: Vary from 4 to 10’ Faces may be rough-sawed, plain, or molded in a variety of patterns.

Plaster

The most popular wall covering. It is made of powdered gypsum to which other materials are added to improve drying time.

A plastered wall system includes: A base support,

such as metal or gypsum lath

Coats of wet plater

Cement board

Definition: A versatile fiber-

reinforced cement panel material that is used as a base (underlayment) for finishing materials used on walls, floors, and countertops.

Fireproof, & water and impact resistant

Special Finishes

These include a variety of products and materials: Brick Stone Glazed Tile Plastic Tile Plastic Laminates

Often found in kitchens and bathrooms

Ceilings can be covered with many of the same materials used for walls.

Composition tiles are especially suitable because they are easy to install.

Drywall Construction

Drywall materials, such as gypsum wallboard, (shown on left) are the most common coverings used in modern construction b/c: It saves time Dries faster than

regular plaster

Single Layer Construction* Cover ceiling first, then walls.

Method One:

Parallel

Long edges of panels run in the same direction as studs and joists.

Method Two: Perpendicular

Long edges of panels are at right angles to studs and joists.

Generally more prefered method.

In either method, vertical wall joints must fall over and center on studs. Both parallel and

perpendicular are shown to the right

Carpenter will use whichever method has fewer joints.

Measuring and Cutting

1. Score face with sharp knife pulled along straight edge, cut should penetrate the paper and enter the gypsum core

2. Support main section of sheet close to scored line

3. Snap the core by pressing downward sharply on overhang.

4. Support the cutoff with other hand

5. Score the backing paper, as shown on right, and snap the cutoff upward

6. The cut can be smoothed with file or sandpaper

Nails and Screws

For single layer const., nails are spaced no further than 7” (ceiling) and 8” (wall). Keep 3/8” from ends and edges (On right) drywall fasteners

Walls Wallboard must

be drawn tightly Start nailing at

abutting edge Nail the field (area

between edges) first Drive nails

straight

Ceilings Double nailing

method of attachment ensures firm contact with framing

Nails in field of board should be spaced 12” on center

After panel is secured, another nail is driven approx. 2” from first

Adhesive Fastening

Produce a sturdier wall that is more resistant to impact sounds Some have flammable solvents Application: Apply continuous bead to the center of all

studs, joists, or furring. Should be ¼ to 3/8” wide

Use temporary nailing or bracing to ensure full contact of the wallboard.

Joint & Fastener Concealment

1. Apply a bedding coat of compound into the depression formed by the tapered edges of board over all butt joints

2. Center reinforcing tape over joint and smooth out.

3. Press tape by drawing 5-6” knife along joint with pressure

4. Apply skim coat over tape.5. Apply second coat over tape.6. Feather edges and apply third coat.7. Sand if necessary.

Corners

Outside corners are reinforced with a metal corner bead.

Fasten by nailing into wallboard and frame

Conceal with joint compound

Internal corners Coat joint compound

to both sides Fold tape along center

and smooth

Double Layer Construction

Also called two-ply Double layer

wallboard apps. over wood framing

Base can be drywall or backing board A gyp. board with a

gray liner paper on both sides

Attaching the Layers

Base layers are applied to framing with staples, nails, or screws The finish layer is laminated to base layer with an adhesive or compound Joints should be offset at least 10”

from the joints of base layer

Adhesive is usually applied to entire surface

Boards

Cement board Manufactured from a slurry of portland

cement reinforced with polymer-coated fiberglass mesh embedde3d in both sides.

Rigid or flexible

Moisture Resistant (MR) Wallboard Plywood processed to withstand the effects

of moisture and high humidity light green facing can be used as base under ceramic tile and

other nonabsorbent finishing materials

Veneer Plaster A high-strength material applied as a coat

less than 1/8” thick Dries rapidly one- or two- coat application

Predecorated Wallboard Usually applied vertically Walls must be dry before installation Use of adhesive to bond panels is common

Wallboard on Masonry Walls

Two methods of preparing masonry walls for interior finish:

(top) Wallboard can be attached to metal furring channels. Rigid insulation is used

(bottom) Wood furring strips and blanket insulation

Installing Plywood

1. Before, panels should be adjusted to room temp. and humidity

2. Plan layout, begin at corner3. Cut upward against the panel face4. Attach directly to wall studs with

nails or adhesives5. Recommended use: ¼” plywood

over ½” gypsum wallboard base

Plaster

Qualities: Beauty, durability,

economy, fire protection, structural rigidity, highly adaptive to shapes, and sound resistance

made from gypsum

Plaster Base

Sheet materials and metal lath Plaster base materials:

A. Gypsum lath

B. Insulating fiberboard lath

C. Perforated gyp. Lath D. Expanded metal

lath

Plaster Materials & Methods

Three-coat work Scratch coat

Applied directly to plaster base It is cross-raked after having stiffened

Brown coat Applied and leveled with the grounds and screeds. A

long flat tool called and darby and rod are used Finish coat

Applied when third coat is somewhat dry

Two-coat work Scratch coat and brown coat are applied

almost at the same time

Ceiling Tile

Can be installed over engineered metal strips, wood furring strips, solid plaster, drywall, or smooth continuous surfaces Many materials can be used Standard size is 12”X12”

Estimating Materials

Determining Area of Rooms Ceiling area is usually the same as floor area

Multiply length times width Wall area

add all the wall lengths together and multiply by the wall height

Sheet Materials Always plan to use the longest practical

sheet. Divide total length of walls by the width of sheets to

find the number of sheets needed Estimate each room separately

Estimated Solid Paneling Based on nominal and unfinished

size Calculate the square footage of the wall

to be covered then multiply by the various factors taken from lumber tables:

For 1x6 tongue and groove boards, use 1.17 For 1x8 tongue and groove boards, use 1.16

On standard vertical applications, add 5% for waste

Gypsum Lath Produced in smaller sections than full

sheets Figure the area of the ceiling and add to this

the area of the walls (length of walls x height) Prices are normally based on square yards Ceiling tile are estimated by figuring the

area to be covered (square footage) Round up