Proper Installation Technique Part 1
In the informative video, Chris Hines, Technical Manager of Boral Stone Products, opens by explaining the adhered veneer system. The first step is protecting the transition from foundation to the beginning of the framing section. He then moves into the installation of the two layers of the water resistant barrier (WRB) system. Once the layers of WRB are installed, the next step is the lath. The lath is the most important because it transfers the weight of the system into the frame. He next discusses the scratch coat.
At this point he takes a break and talks about substrate options, like a concrete wall. Cleaning to remove form release agents, and texturing via bead blasting, may be necessary to prepare the surface. With CMU block or brick, those products typically already have enough texture to bond to, and you can should be able to go right to the scratch coat or even the bond coat. He briefly covers a few other wall substrates.
He then returns to the installation, beginning with requirements for clearance. All adhered veneer systems require clearance from either grade or paved surface, and Chris covers several examples. He then addresses water management technique.
Next, he covers a technique for creating the best bond when sticking stones to the wall. He discusses some tricks for preventing the drier scratch coat and drier stone from extracting the water from your mortar, preventing it from being as strong as it could be. Next he discusses inspection of the stones themselves and preparation, removing any loose particles with a wire brush or knocking off any over-pour.
He talks about two techniques for applying the setting bed of mortar. Method A: The first step is a back butter step. And the second is to apply the mortar setting bed, to a thickness of approximately 3/8″. Method B: This is an adaptation of the stucco system. The setting bed is troweled onto the wall itself, as if it were a stucco brown coat. The stone will still be back-buttered, just as it was in Method A, and then the stones are pressed into the mortar. Following the proper method of applying the stones, he addresses some improper techniques.
As the stones are placed, he demonstrates how additional mortar can be added to the joints with a grout bag. The mortar is then allowed to become thumbprint hard. It can then be tooled with a standard brick joining tool or a stick. The mortar is then allowed to become dry and crumbly, at which time it can be cleaned up with a stiff whisk broom.
Chris finishes with a review of everything covered in the tutorial. This is quick summary of the contents of the video. Please take the time to watch Chris Hines as he covers installation technique in detail.
Installation Guide – Cultured Stone©
MVMA Installation Guide