C33 Wallcovering Installation and Preparation 5 — Questions and Answers
Question 1: When a wallcovering strip begins to slide or slip after being hung, the most likely cause is:
- The pattern repeat is too large
- Too much paste was applied or the paste is too thin (Correct answer)
- The wall was over-primed
- The strip was booked too long
Correct answer: Too much paste was applied or the paste is too thin
Slipping or sliding strips typically result from paste that is too wet, too thin, or applied too heavily, reducing friction on the wall.
Question 2: What is the purpose of applying a primer-sealer to new drywall before hanging wallcovering?
- To add texture to the surface
- To prevent the drywall paper from tearing when wallcovering is removed in the future (Correct answer)
- To speed up drying time of the wallcovering paste
- To fill small holes and imperfections
Correct answer: To prevent the drywall paper from tearing when wallcovering is removed in the future
A primer-sealer on new drywall prevents the facing paper from bonding directly to the drywall, allowing future removal without damaging the substrate.
Question 3: Which of the following wallcovering patterns requires the most material due to waste during pattern matching?
- Random match (no repeat)
- Straight match
- Drop match with a large repeat (Correct answer)
- Tone-on-tone texture
Correct answer: Drop match with a large repeat
Drop match patterns with large repeats generate the most waste because each strip must be offset by half the repeat, requiring significantly more material.
Question 4: When hanging wallcovering on a wall with an out-of-plumb corner, the best practice is to:
- Force the strips into the corner and overlap at the ceiling
- Plumb each new wall section independently from the corner (Correct answer)
- Skip the corner entirely and patch it later
- Use a flexible non-woven material only
Correct answer: Plumb each new wall section independently from the corner
Because corners are rarely perfectly plumb, a new plumb line should be established on each wall section after turning the corner.
Question 5: What is the correct way to clean paste off the face of vinyl wallcovering during installation?
- Use a dry cloth to rub the paste off immediately
- Wipe with a clean damp sponge, rinsing frequently (Correct answer)
- Leave the paste to dry and then peel it off
- Use a mild solvent to dissolve the paste
Correct answer: Wipe with a clean damp sponge, rinsing frequently
A clean, damp sponge rinsed frequently removes paste from vinyl faces without smearing or leaving residue.
Question 6: Which type of adhesive is recommended for hanging heavy commercial-grade wallcovering?
- Standard wheat starch paste
- Clear ready-mixed vinyl adhesive for lightweight paper
- Heavy-duty clay-based or strippable adhesive rated for Type II wallcovering (Correct answer)
- Premixed all-purpose joint compound
Correct answer: Heavy-duty clay-based or strippable adhesive rated for Type II wallcovering
Heavy commercial-grade (Type II) wallcovering requires a heavy-duty adhesive with sufficient open time and holding power to support the material's weight.
Question 7: If wallcovering bubbles appear shortly after installation, the installer should:
- Pierce each bubble with a pin and inject additional paste
- Allow 24–48 hours for the bubbles to dry out naturally before taking further action (Correct answer)
- Immediately remove and rehang all affected strips
- Apply heat with a hair dryer to shrink the bubbles flat
Correct answer: Allow 24–48 hours for the bubbles to dry out naturally before taking further action
Small bubbles often result from trapped air or moisture and typically flatten on their own as the paste dries over 24–48 hours.
C33 Wallcovering Installation and Preparation 5
When a wallcovering strip begins to slide or slip after being hung, the most likely cause is: