Adhered Manufactured Stone Veneer (Part 3)

JNX-clusives

Chips Off the Old Block

and other ruminations about masonry 

by

Larry D. Jenks

 

Manufactured Stone Veneer

In my last installment, I promised to provide some installation details for the Adhered Manufactured Stone Veneer system. I have read many from a variety of different manufacturers, and I am going to summarize them for you here... with this caveat -- the Adhered Manufactured Stone Veneer (AMSV) industry is not currently recommending the use of a drainage plane in their installations. The final word on this has not yet been written, but I find it difficult to recommend the system without one. So the drawings I have provided here show one -- in this case, it is Sure Cavity by Masonry Technologies, Incorporated, which is a recycled plastic material with a built-in filter fabric that looks like this...

  There are other manufacturers that make drainage plane (and drainage mat) products, such as DC14 Drainage Mat manufactured by Greenguard, or fibrous entangled filament drainage mats. You can choose one that you like.

 

Adhered Manufactured Stone Veneer Installation Recommendations

(taken from the Masonry Veneer Manufacturers Association Installation Guide, 3rd Edition)

(These recommendations apply to wood framed exterior walls made with moisture sensitive- materials; the application is slightly different when applied to concrete or masonry walls, but I am not going to address those applications in this installment)

The first thing that a drainage systems needs is a slotted (or draining) weep screed. I like the ones made from galvanized sheet metal, but others made from plastics are also available. A draining weep screed looks like this...

 
According to the  Masonry Veneer Manufacturers Association (MVMA), the weep screed should be installed so that the bottom of the AMSV system is at least 4" above the surrounding grade.

  

 

Then a 2-ply water resistant barrier should be installed. The plies should be installed in a shingle-lapped manner, overlapped by 2" (6" at the vertical joints).

Figure 3-- Add 2 layers of Water Resistant Barrier

Then the drainage plane or drainage mat, or rainscreen should be installed over the water resistant barrier...

Figure 4-- Add rain screen drainage plane

Figure 5-- Enlarged view of rainscreen drainage plane

Figure 6-- Filter fabric comes already installed on rainscreen drainage plane

The MTI drainage rainscreen is already covered with a filter fabric to keep the mortar scratch coat from filling the drainage cavities.


Then metal lath is installed. I have seen many installations on houses around where I live that have used chicken wire, but I have found no recommendations from any source that recommend that.

Figure 7

Now the wall is ready for the mortar scratch coat, or setting bed. This is what holds the manufactured stone in place. 

Figure 8

Then the manufactured stone must be installed with great care and skill...

Figure 9

Please give me a call if you would like to discuss this further. I'm always happy to talk with you about these kinds of things (or a little baseball, too).

Until next time...

NOTE: This document was prepared by the JNX Group, LLC and is disseminated for informational purposes only. Nothing contained herein is intended to revoke or change the requirements or specifications of the individual manufacturers or local, state and federal building officials that have jurisdiction in your area. Any question, or inquiry, as to the requirements or specifications of a manufacturer, should be directed to the manufacturer concerned. The user is responsible for for assuring compliance with all applicable laws and regulations.

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