How do I install metal lath for stone veneer?

Metal lath goes up over your weather-resistant barrier. Use 2.5 lb galvanized diamond m...#

Metal lath goes up over your weather-resistant barrier. Use 2.5 lb galvanized diamond mesh, attached every 6" with galvanized roofing nails into the studs. Overlap seams 1" and run the lath horizontally with the cups facing UP — that's how it grips mortar.

Metal lath is the foundation of every successful exterior cultured stone install. It's a galvanized steel mesh that gives mortar something to grip when there's no masonry behind it. Here's what matters:

Weight matters. Use 2.5 lb diamond mesh (heavier = stiffer = less crack risk). Skip the 1.75 lb stuff — it flexes too much and your scratch coat will crack within a year.

Cups face up. Diamond mesh has a directionality. Run your hand across it — one direction will feel smooth, the other will catch. The catching direction is 'cups up' and that's how it should be installed. This is what gives mortar bite.

Nail spacing: every 6". Galvanized roofing nails through the lath into studs at 16" OC, plus into the WRB-covered sheathing in between. Closer in cold climates (4" spacing) to handle freeze-thaw cycles.

Seams overlap 1". Whether you're running horizontally or vertically, the next sheet should overlap the previous by at least 1". Tie the seams every 12" with galvanized wire if you're paranoid.

Corners need extra. Cut a strip of lath and bend it to wrap around outside corners. Otherwise the mortar will crack at the corner within the first winter.