Mar . 05, 2024 14:51 Back to list

How to Prepare Brick For Stone Veneer

PROJECT OVERVIEW

TOTAL TIME: 1 - 2 hrs
YIELD: Scratch coat on brick for manufactured stone veneer

SKILL LEVEL: Intermediate
ESTIMATED COST: $20 to $50

If you have an uninspired brick fireplace or brick interior wall that looks dated, you might be looking for ways to improve its appearance. Painting or staining your brick are two ways to give it a quick style refresh. Another option is to install stone veneer directly over the brick. Best of all, you can do this without ripping out the existing brick. An important step is to prepare the brick for the veneer.

While you can install manufactured stone veneer over brick, it's not as easy as troweling mortar directly onto the brick and applying the veneer. As with other surfaces, the brick must provide a stable surface for the veneer layer.

One surface preparation method starts with a wet scratch coat that's applied to the brick before you install the veneer. Another method avoids the scratch coat and uses cement board. Essentially, the cement board becomes the scratch coat.

2 Types of Stone Veneer

Manufactured Veneer

Manufactured stone veneer is made from Portland cement, aggregates, and iron oxide pigments.

Manufactured stone veneer is heavier and more substantial than polymer faux panels, but not as heavy as real stone. It comes in individual stones that you fit together piece by piece and mortar onto the wall, just like real stone. Manufactured stone veneer also often comes with pre-made outside corners that make the finished product appear more similar to a natural stone installation.

Natural Stone Veneer

Natural stone veneer is carved from the Earth, beautiful, heavy, and difficult to work with. Natural stone veneer is available only from stone yards and can be expensive. However, natural stone can be workable when sliced into a thin veneer in the factory. This makes the stone lighter and easier to handle.

Tip

Natural stone veneer is not common, but it is the most accurate and realistic form of stone veneer you can purchase.

Equipment / Tools

Drill
Tin snips
Trowel

Materials

Metal lath
Masonry screws

How to Prepare Brick For Stone Veneer With a Scratch Coat

Prepare Brick Surface

Sand- or water-blast the paint, dirt, or oils so that you have a raw, fresh, porous (but not crumbling) surface. Some masons say that this is an adequate surface for accepting a scratch coat.

Tip

Avoid applying the scratch coat directly to painted brick. Painted brick will not accept the scratch coat because the surface is not porous. The paint must be removed first.
Install Metal Lath

Metal lath is an acceptable surface that will allow you to apply veneer to brick. First, apply corrosion-free 18-gauge metal lath to the brick with masonry fasteners. Make sure that the cups of the lath are pointing outward. Overlap both the horizontal and vertical seams by 1 inch. Be sure to wrap the lath around corners (both inside and outside) rather than applying two separate pieces of lath. This gives the framework more stability.
Apply Mortar

The scratch coat of mortar is troweled over the metal lath. Be sure to force the mortar through the holes of the lath. Trowel the top of the mortar smooth to accept the veneer stone.

How to Prepare the Brick With Cement Board

For do-it-yourselfers, an often better option is to install a layer of cement board over the brick, then install the veneer on the cement board. This serves the same purpose as the scratch coat but, in some ways, is better.

The cement board is already hard and flat even before you apply it to the brick. With a scratch coat, you need to work the surface with a trowel to flatten the mortar.

The cement board works essentially like the metal lath and mortar method, but installation is cleaner and allows you to begin veneering immediately.

Cement board is screwed or nailed to the brick, acting as a new underlayment and bypassing the brick. Most professionals recommend mortaring down the cement board on the brick. The cement board can even bridge over some minor gaps, cracks, and imperfections in the brick.

Finally, a mortar layer is applied to allow the manufactured stone veneer to stick to the cement board. You'll need to press each stone firmly into the mortar for several seconds for it to properly stick.