Fifteen minutes with a tape measure and a notepad saves a second trip to the store — and decides how good the finished wall looks.

Measure and do the math:

• Measure the wall area: width × height, in inches
• Square feet = (width × height) ÷ 144 — each 12×12" tile covers exactly 1 sq ft
• Add 10–15% extra for cuts, breakage, and future repairs

Example: 48" × 72" wall = 24 sq ft → 24 tiles + 3 spare = 27 tiles

Decide the look:

• Straight grid is the standard; a diagonal (diamond) layout looks dramatic but adds 45° cuts on every edge tile
• Tile finishes: standard silver, antiqued, smoked, or tinted
• Buy every box from the same manufacturing lot — batches vary slightly in tint, and a mirror wall shows it

Plan where the cut tiles land:

• Sketch the wall on graph paper, one square per tile
• Center the layout so cut tiles fall at the edges — never in the middle of the field
• If the layout leaves a sliver (under ~2") at an edge, shift the whole grid half a tile to fatten it up

Measure the wall, mark the center point, and sanity-check the tile count before opening a single box.

The tiles will follow whatever surface and lines you give them. Give them a sound, clean wall and a true center cross.

Know your surface — will the mastic hold?

The mastic only holds what the wall's surface layer holds. It will grip paint perfectly — and if that paint is flaking off the wall, the tiles leave with it. Per Bohle's guidance for their Xtragrip mirror adhesives:

Make the wall sound, smooth, and clean:

• Fill every hole and crack with spackling compound; sand patches flush with 120-grit
• Porous walls (bare plaster, concrete, wood): brush on Xtraprime — the special adhesion primer made for mirror mastic — undiluted, and give it about an hour to dry. Ordinary paint or drywall primer is not a substitute
• Vacuum the dust, wipe the wall down, then do a final pass with isopropyl alcohol — the wall must end up clean, grease-free, and fully dry

Snap the center cross:

• Mark the center point of the wall area
• Draw a vertical line through it with a level; snap a chalk line for long runs — then wipe the loose chalk off and pencil over the line where you need it. Chalk is dust, and dust is the enemy of the bond
• Draw a horizontal line through the same point, perpendicular — verify with the level, not by eye
• Large walls: add extra grid lines every 2–3 ft to keep far rows honest

Dry-run before any adhesive:

• Test-fit a row of tiles on the floor against your marks, spaced with the same 1/16" gaps you'll use on the wall — across an 8-tile row the gaps add up to nearly half an inch, which moves where your edge cuts land
• Confirm the edge tiles aren't slivers
• Take a photo of the marked wall; you'll cover your lines as you work

Patch, sand, clean: the unglamorous step every good wall stands on.

A true vertical and horizontal through the center — checked with the level, never eyeballed.

The heart of the job. Vertical beads, firm presses, consistent hairline gaps — and never slide a tile.

Gun the mastic on:

• Use Bohle Xtragrip MS Polymer in the caulking gun — it's formulated to be safe on the silver backing (DIN EN 1036); ordinary construction adhesive corrodes it into black blotches
• Cut the cartridge nozzle for a bead about 1/4" wide — Bohle caps bead width at 10 mm (about 3/8")
• Lay vertical beads on the wall, inside the space the next tile will cover — a bead every 3–4", three or four per tile, the way the shop photos show
• Keep the outer beads an inch or two in from the side joint lines — a bead at the edge squeezes into the open joint when you press
• Keep each bead to about 8" — roughly 2" short of where the tile's top and bottom edges will land (Bohle caps a bead at 200 mm) — so pressing never squeezes mastic toward the joints
• Beads, never dots or troweled patches — Bohle is explicit: strips flex with the wall and leave air paths; blobs make stress points and trap moisture
• Vertical matters: upright beads leave open channels behind the glass, and tile over tile those channels line up into flues running the height of the field — the wall breathes bottom-to-top, which the mastic needs to cure and the backing needs to stay dry. The 1/16" joints are the intakes; the open top edge is the exhaust

Vertical beads of Bohle mastic gunned onto the wall — one tile's worth at a time, stopped short of the joint lines.

Set the first tile at the cross:

• Line the tile's corner up with the center intersection — the whole wall grows from this tile
• Press it flat with both palms, firm and even, so every bead spreads and grips

Work outward, joint by joint:

• Leave a 1/16" gap around every tile — 1/32" is the absolute minimum. Glass expands, houses settle (especially new construction), and hard glass-to-glass contact grinds and chips the edges as everything moves
• The gaps are also part of the ventilation: open joints feed air into the bead flues. At 1/16" they still read as hairlines — the "seamless" look survives
• Keep the gap consistent with a 1/16" tile spacer or two playing cards as a feeler; slip it against the last tile, set the next, pull it once the bead grabs
• Grow outward from the center in all directions, section by section
• Check the rows with a level or straightedge every 3–4 tiles — drift compounds fast
• Wipe any adhesive squeeze-out off the glass immediately, before it sets

Flat palms, firm press — set exactly on the center cross.

The joint: a consistent 1/16" hairline — expansion room and airway, reading as a fine line.

Score once, snap once. Hand-cutting mirror tile is easier than it looks — if you let the score line do the work.

Measure each gap on its own:

• Walls are never square — measure the gap for every edge tile at both ends, top and bottom
• Subtract the joint gap on both sides of the cut piece: 1/16" at the tile joint, and the same again where glass meets wall, ceiling, or floor — glass should never touch the structure hard. Where the edge is exposed, trim covers it later; everywhere else the gap simply stays open
• Transfer the measurement to the tile and mark the cut line on the mirror face

Score:

• Tile mirror-side up on a padded bench, straightedge clamped along the line
• Oil the cutter wheel, then score in one smooth continuous pass, firm and even

Snap:

• Line the score up with the bench edge over a folded towel, overhang out
• Hold the tile flat with one hand, press the overhang down firmly — it parts along the score
• Narrow strips: use running pliers instead of the bench edge
• Smooth the cut edge with 220-grit used wet, one or two light passes

Face up, straightedge guiding, one oiled scoring pass.

Score line on the padded bench edge — press down and it parts clean.

Trim the exposed edges, polish the glass — and leave every gap open. The airway is the finish.

Trim the exposed edges:

• Cover raw outer tile edges with aluminum J-molding (cleanest) or plastic edge strip (cheapest)
• Cut trim to length with a hacksaw or utility knife; bed it in short dabs of the same mastic, not a continuous line — air has to keep moving behind the glass

Every gap stays open — no caulk on this system:

• Nothing gets filled. Not the joints, not the perimeter, not the bottom edge. The gaps are the wall's drainage and its airway, and both jobs end the moment they're caulked
• Splash that finds an open joint drains down behind the glass and dries through the flues. Caulk the bottom and you've built a dam that holds that water against the backing instead
• The open top edge is the exhaust, the joints are the intakes — none of it is an unfinished edge
• Found caulk on an older wall? Cut it out and leave the gap open — see Troubleshooting for the black creep it causes

Final inspection and polish:

• After full cure (24–48 h), press each tile gently — it should not flex, rock, or click. A tile that gives isn't gripped by all its beads: lift and re-set it now, not after it falls
• Don't tap-test for "hollow" spots — that's floor-tile advice. A bead-hung mirror tile is mostly hollow behind by design; hollow is normal, movement is the failure
• Shave stubborn adhesive residue with a razor blade held nearly flat against the glass
• Polish with ammonia-free glass cleaner — spray the cloth, not the wall, so cleaner never wicks into the joints
• Store the spare tiles flat, cardboard between them, labeled with the lot number

J-molding pressed over the raw outer edges — and every gap left open. The silicone in the shot stays in its tube on this system.