Have you been facing adhesion problems with your application of our Pro Stack stone veneer? These 3-inch modular pieces aren’t applied with a mortar joint and have their own special installation process. We want to offer a helpful breakdown of the likely causes of adhesion issues and the best solutions to prevent and fix them.

Common Causes

– Jack Frost is at it again

If you’re experiencing issues and you’re located in the northern regions of our continent, Winter moisture is the most likely culprit. When your Pro Stack has any space between the mortar and the wall, it leaves a perfect hiding spot for moisture. As it freezes, it creates pressure against the Pro Stack. As the temperatures and moisture levels fluctuate, the application weakens and the veneer pops off.

– Wrong use of mortar

Pro Stack is supposed to be a tight-fitted layout because these pieces are not applied with a mortar joint. Where seasonal change causes moisture buildup and expansion, it is especially important to apply mortar in a way to avoid moisture pockets. While we do offer a basic installation guide for our stone veneer, it is important to go through our in-depth MSV Installation Guide before applying the veneer.

Proper Pro Stack Application

– Use the Tight Stack method

Shown below is an overview of special considerations for Pro Stack Installations

An instuction sheet to explain how to install pro stack

You can also refer to page 13 of our MSV Installation Guide, you’ll find the proper application method for Tight Fitted Adhered Manufactured Stone Veneer Application. You’ll see in this section the correct mortar method:

“The back of each AMSV should be entirely buttered with mortar to a nominal thickness of 1/2 in. (13mm). Cover the entire back of the AMSV, not just the perimeter. Buttered AMSV should be firmly worked onto the scratch coat and slid slightly back and forth to set the AMSV.”

It is also important to make use of mortar squeeze out to completely cover the scratch coat. Apply Pro Stack from the corners to the middle, and from the bottom to the top.

– Use a more adhesive mortar

Make use of products like Acryl 60 and polymer-modified mortars. If you’ve done the necessary application process and still had issues, this may be the next step. Polymer-modified mortars are stronger mortars because it is more fluid. It is easier to handle with results in fewer gaps.


It is important to tightly stack your Pro Stack with enough mortar, especially for exteriors exposed to seasonal change. Please read our MSV Installation Guide before proceeding with your Pro Stack project.

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