I5 - Describe Drywall Flashcards
What is Type-C drywall board?
Fire-rated board that has a better fire resistance than Type X due to additives.
Where is backer board used?
As an underboard in multi-layer applications.
What are the standard lengths of drywall board?
7, 8. 10, 12 and 14.
What is the purpose of controlled density board?
Controlled Density Boards - Intended to be installed on ceilings to prevent sagging. Typical CD board 1/2 “ thick so that offcuts and extras can be used on walls.
Why is moisture-resistant drywall not recommended for use behind ceramic tile in a shower?
Moisture-resistant drywall is not actually waterproof. Use waterproof cement board.
What type of trim piece is used around a bifold door opening?
J-Bead
What method of applying corner bead is considered best?
Glued-on corner beads - faster and resists cracking
What is the purpose of drywall clips?
To support board where backing was missed.
When is a meth taped used?
When speed is a concern used with quick-dry.
When is mesh tape used?
When speed is a concern, used with quick-dry mud.
What is the advantage of using topping compound as opposed to all-purpose compound?
Topping compounds shrink less than all purpose compounds.
Gypsum wallboard is known as:
Gyprock, sheetrock and drywall.
Sheets come in what thickness?
1/4 to 5/8” thick.
Drywall comes in what widths?
48” or 54” and 24”
Drywall comes in what lengths?
7 to 14’ long - Standard lengths of 7’, 8’, 10’, 12’, and 14’
What is Drywall?
Made from gypsum plaster mixed with fiber that is sandwiched between two layers of heavy paper.
Standard gypsum is used in what applications?
Residential and commercial buildings in single-layer application.
Why is textured ceiling mainly done?
To reduce labor costs.
Fire rated, or Type X board:
Fire resistant board that is used to build fire-separations in multi-family buildings and between commercial buildings.
How does Type X improve fire-resistance?
Adding reinforcing fibers to the core.
1) Fibres reduce cracking when exposed to fire, increasing length of time before failure.
2) Type C has even more fibres than type X and has a shrinkage-compensating additive.
Additive in Type C Drywall expands in heat and helps drywall how?
Additive in Type C drywall expands under heat and compensates for shrinkage.
Type C can create many hour rated exterior curtain wall, interior partition and shaft walls?
Type C can create 2 hour exterior curtain walls and interior partition
4 hour-rated shaft walls.
Backing board is used in:
Multi-Layer application. Face of backer board does not have paper-face, edges of backer board not finished or tapered either.
Moisture resistant drywall is used in:
Bathrooms and kitchens where higher than normal moisture levels occur.
Not a replacement for Cement-based wallboards which are fully waterproof.
Gypsum sheathing boards:
High moisture resistance for exterior use:
Treated core, type x and type c.
Controlled Density board used in:
1/2” thick, able to span 24” on ceilings without sagging. Heavier than 1/2” board and more difficult to cut.
Vinyl board is:
Plastic surfaced standard drywall board. Extra care taken to avoid damaging corners or edges of these sheets as they are often exposed after being installed.
Core board or Shaft liner
Thick sheet of fire resistant drywall that is used around Elevator shafts and fire exits for fire protection. Sheets can be up to 2” thick.
Type X lath is a fire-resistant drywall board used for :
It is used under a skim coat plaster finish.
Corner bead:
Drywall finish is completed at exterior corners with corner beads. Bead is applied over board and then filled with drywall compound.
Glue on is faster and resists cracking - rather than nail.
Lead-lined board
Used for finishing the walls of X-Ray rooms. The lead lining protects the hospital staff from exposure to radiation from the X-Ray equipment.
J Bead - is used for:
Around bi-fold door openings.
Around a window when applying a drywall return, what sort of application would you use?
Plastic J bead, it protects drywall from moisture and will not rust.
Bugle around the head of the screw is rounded where it fits fits into drywall why?
Reduce the tearing of the paper surface.
Drywall clips are used when?
Where backing for screwing is missing.
Control joints are used:
When there are long expanses of finished drywall. They provide an allowance for expansion and contraction to reduce cracking in the drywall.
Acoustic Sealants are used:
All gaps around openings must be sealed when drywall is installed as part of a sound barrier or when used as a vapor barrier.
Gaskets:
Gaskets are used between the drywall and other surfaces to create an airtight barrier when drywall is used as part of an airtight drywall system.
Drywall surface is made vapor-proof by using:
Enamel paint
Expanded Metal Lath:
Where covered ceiling or other architectural features are built, expanded metal lath is used to form a base for the plaster finish.
Tape and Filling Compound for two reasons:
1) Provide a smooth and uniform surface for painting and wallpapering
2) Make a continuous firestop
Production work is done with what mudding tape?
Paper tape
Why is paper tape feathered?
To allow filling the joint without showing the edge of the tape.
Main reason why layers of filler have to be applied:
To fill in the depressions left by the shrinking filler.
Premixing filling compound is preferred because:
It is more efficient to use and has a smoother texture than the job-mixed compound.
All-purpose compound is suitable for:
Applying tape, second coating and finish coating. Can be bought as powder or pre-mixed containers.
Topping compound advantages:
Shrinks less than all-purpose compound and is easier to sand.
