Not a movement joint — perimeters and plane changes get sealant, never a spaced-and-grouted line.
Not for lugged wall tile: some tile is molded with self-spacing lugs, and adding spacers to it fights the tile's own geometry — the first of the line's two honest no-sales.
Not for sheet-mounted mosaic, which spaces itself on its mesh — the second no-sale.
Not a shim for leveling: spacers control joint width in the tile plane, not tile height out of it — lippage is a substrate and bedding problem, and no spacer fixes it.
And not a leave-in-place component: every spacer on this page is temporary tooling, out before grout.
One bag, one size, one job — mixing spacer sizes mid-field to "adjust" is how lines wander; adjustments live in the mortar bed and the snapped lines. Count honestly: flat crosses run one per intersection; tombstones run two per joint side near the corners — either way a floor consumes spacers in the hundreds, and the bag count is unprinted here , so buy by the room, not the exact tile count. Pull timing beats pull technique: too early and tiles drift into their own joints; too late and the pull risks disturbing set tile — the thumb-press check on a sacrificial corner of the field answers it. Keep them out of the thinset: a spacer pressed down into squeeze-out becomes a grout-depth problem at pull time; seat them at tile depth, not bed depth.
Asked before buying
BUYER QUESTIONS, ANSWERED BEFORE YOU ORDER
What size spacer should I buy if I don't know?
This one. 1/8" is the trade default because it absorbs standard ceramic's size variation while keeping a clean contemporary field — the full argument is 2b.
Sanded or unsanded grout with 1/8" joints?
The boundary size itself: the shelf heuristic says sanded at 1/8" and wider, and the grout bag's own instructions rule on the product in your hand.
Flat at the intersections or standing in the joints?
Both are legitimate (cross form assumed). Flat gives maximum control and a harder pull; standing pulls easily and is most setters' field default. Flat crosses at control points, tombstones through the field is a sound hybrid.
Can I grout over spacers instead of pulling them?
No — the one absolute on this page. Grout over buried plastic is a thin section that cracks and ghosts a cross at every intersection, across the whole floor.
When do I pull them?
After the thinset grabs (tiles resist a nudge), before it locks. The window is real but generous; the thumb-test on a corner tile answers it per batch.
How many do I need?
Count is unprinted here (bag quantity unverified) — plan by intersections and joint-sides for your square footage and buy the extra bag; leftover spacers cost nothing and mid-job shortages cost the schedule.
Do I use spacers against the walls?
No — the perimeter is a movement joint: left open, caulked flexible, never grouted. Spacers space tile from tile only.
