Grouting & Finishing Techniques Flashcards

According to the Tile Council of North America (TCNA), movement joints (expansion joints) in tile work should be placed:

Answer: Wherever the tile field changes direction or at structural joints, plus every 8-12 feet in large fields

TCNA guidelines call for movement joints at changes in direction, over structural joints, and within large fields (every 8–12 feet interior, 8–10 feet exterior) to accommodate thermal and structural movement.

What is the correct procedure when grout is starting to set up in the bucket before you finish the job?

Answer: Discard the batch and mix a fresh, smaller quantity

Re-tempering grout by adding water after initial set compromises its strength and bond; the proper solution is to discard and mix a fresh batch.

A tile installer notices that grout joints on a newly completed wall installation appear sunken or concave. This most likely indicates:

Answer: The grout was not packed sufficiently into the joint depth

Sunken or concave grout joints result from insufficient packing during application, leaving the grout below the tile face rather than flush with it.

Which type of grout is most appropriate for a food-preparation countertop installation where stain and chemical resistance are paramount?

Answer: Epoxy grout

Epoxy grout is non-porous, highly stain-resistant, and resists most chemicals, making it the preferred choice for food-preparation countertops.

During grout cleanup, the tile installer should change the rinse water in the bucket:

Answer: Frequently to prevent redepositing dissolved grout back onto the tile surface

Dirty rinse water contains dissolved grout solids that will redeposit and harden on tile surfaces as a haze if not changed frequently.

What is the recommended minimum cure time before sealing a cementitious grout in a typical interior application?

Answer: 7 days (168 hours)

Most grout sealers require cementitious grout to cure for a minimum of 72 hours, though many manufacturers and industry guidelines recommend waiting 7 days for full cure before sealing.

A specifier calls for 'unsanded grout' on a project. At what joint width would you flag this as potentially problematic?

Answer: 3/16 inch

Unsanded grout is recommended for joints up to 1/8 inch; joints at 3/16 inch or wider risk excessive shrinkage and cracking without sand as aggregate filler.