Manufactured stone veneer is sold two ways: flats by the square foot and corners by the linear foot. Get the math wrong and you either run short halfway through the installation or end up with $400 of unreturnable material in the garage. Here's how to count it right.

Flats and corners — the 0.75 rule

Flat stones cover the field of the wall and are sold by the square foot. Corner stones are L-shaped pieces that wrap outside corners — the long leg goes on one face, the short leg on the adjacent face, hiding what would otherwise be ugly butt joints. Corners sell by the linear foot.

Each linear foot of corner replaces about 0.75 ft² of flat coverage. So a wall with 30 lin ft of outside corners on a 200 ft² gross area really needs 200 − (30 × 0.75) = 178 ft² of flats plus 30 lin ft of corners. Add 10% waste to both for cuts and breakage.

The stone veneer calculator deducts corner coverage automatically and returns flats, corners, mortar, and lath all at once.

The lath layer is not optional

Every code-compliant manufactured stone install over framing or sheathing needs 2.5-lb diamond mesh galvanized metal lath stapled through the sheathing into the studs at 6 in on center, plus a weather-resistive barrier (two layers of grade D paper, or a coded WRB) under the lath. Skip the lath, skip the WRB, or fasten the lath to sheathing only — and the veneer fails. Usually within five years.

A standard 27" × 96" lath sheet covers 18 ft². A 200 ft² wall takes 12 sheets plus laps. The calculator returns sheet count.

Direct-bond installs are allowed only over masonry, concrete, or brick — substrates that already provide bond. Frame walls always need lath.

Mortar — joint style decides the bag count

Two install styles drive different mortar consumption:

  • Full mortar joint — traditional grouted look, joints visible between every stone. Roughly 3 bags of 80-lb Type S per 100 ft² of veneer.
  • Dry stack — stones butted tight with only the back-buttering and setting bed. About 1 bag per 100 ft².

Polymer-modified bagged mortar (sometimes labeled "stone veneer mortar" or "Mason Mix") is what most manufacturers spec — standard Type N often doesn't bond well to the back of cast veneer. Read the spec sheet for the brand you're installing before mixing.

Cut work and waste

The 10% waste factor is a baseline. Bump it to 15% on:

  • Walls with more than 6 lin ft of corner per 100 ft² of face (lots of cut starts)
  • Tight pattern requirements (some manufacturers specify no two stones of the same shape touching)
  • Masonry novices — pros waste roughly half what a first-time installer does

Save the offcuts. Most veneer manufacturers ship pieces in blended pallets where every box has the same color and shape mix — the offcuts from one wall become field starts on the next.

Common errors

Counting both faces of every corner. One L-shaped corner piece covers both adjacent faces at the corner — don't double-count it in your lin ft tally. Measure vertical run of the outside corner from grade to soffit.

Skipping the weep screed. The bottom of the lath layer needs a weep screed or a 2-inch gap above grade so any moisture that gets behind the veneer can drain. Install on grade and water sits in the lath cavity, freezes, and pushes the veneer off the wall.

Using the wrong staples. Galvanized roofing nails or fence staples corrode behind the veneer within five years. Hot-dip galvanized or stainless lath staples only.

Quick FAQ

How much stone veneer do I need for a 30 ft × 8 ft wall? Gross area = 240 ft². Subtract openings and account for corners with the calculator. With one outside corner of 8 lin ft, you need ~228 ft² of flats plus 9 lin ft of corners, plus 10% waste.

Can I install stone veneer over old siding? No. Strip to sheathing, install WRB and lath, then veneer. The siding underneath will fail before the veneer does and trap moisture against the framing.

What's the height limit? Manufactured stone veneer over framing is generally limited to 30 ft total wall height per code, with intermediate flashing every story. Above 30 ft, switch to natural stone with structural ties.

Estimate only. The stone veneer calculator uses standard manufacturer averages. Coverage, mortar yields, and corner ratios vary by product line — verify against the spec sheet for the SKU you're installing before ordering.