Grouting & Finishing Techniques Flashcards

When grouting natural stone tile with an inherently porous surface (such as tumbled travertine), what pre-treatment step is critical before applying grout?

Answer: Apply a grout release or sealer to the tile face

Porous natural stone must be sealed or treated with a grout release product before grouting to prevent grout from permanently staining or bonding into the stone's pores.

On a steam shower installation, which movement joint filler material is most appropriate?

Answer: 100% silicone sealant rated for high-humidity and temperature cycling

Steam showers expose sealants to constant high humidity and temperature swings, requiring 100% silicone sealant with a steam-rated or high-temperature rating.

What does 'striking' a grout joint refer to in tile finishing?

Answer: Tooling the joint surface to a uniform concave or flush profile

Striking a grout joint means using a tool to shape the exposed surface to a consistent concave, flush, or V-shaped profile for a finished appearance.

A client reports that grout in their outdoor patio is cracking and crumbling after the first winter. The most likely cause is:

Answer: Failure to use a freeze-thaw resistant grout or inadequate drainage causing water infiltration and freeze-thaw damage

Outdoor grout exposed to freeze-thaw cycles must be rated for exterior use and the installation must provide adequate drainage; standing water in joints expands when frozen and destroys the grout.

When matching grout color to existing tile in a repair situation, which factor most significantly affects whether the new grout will match the old?

Answer: The age and weathering of the existing grout, which shifts color over time

Existing grout color changes significantly over time due to soiling, UV exposure, and mineral deposits, making an exact color match with new grout very difficult.

Which of the following best describes the function of a grout bag when used on rustic stone or brick installations?

Answer: It applies grout under pressure to force it into wide, deep joints without smearing the irregular face surface

A grout bag (similar to a pastry bag) allows the installer to inject grout directly into wide, deep joints on rough surfaces without spreading grout across the difficult-to-clean irregular faces.

According to industry standards, what is the minimum required compressive strength for sanded cementitious grout used in floor tile applications?

Answer: 3,000 psi

ANSI A118.6 requires sanded cementitious grout to achieve a minimum compressive strength of 3,000 psi to withstand floor traffic loads.