Replies

1. GBA Editor
   Martin Holladay|Jun 07, 2013 05:32am|#1

   Andrew,
   I strongly advise you do include a gap between the stucco/lath/building paper and your plywood wall sheathing.

   This article includes the information you need to know:To Install Stucco Right, Include an Air Gap.

2. 
   Andrew Shu|Jun 07, 2013 06:11am|#2

   Thanks for your response. Would the gap be between the lath and building paper or between the building paper and sheathing?

3. GBA Editor
   Martin Holladay|Jun 07, 2013 07:10am|#3

   Andrew,
   The answer can be found in the article I linked to. You'll need at least two layers of WRB material (for example, asphalt felt): One behind the three-dimensional plastic drainage mat, and one in front of the three-dimensional plastic drainage mat.

   In the article, I wrote:

   “If you’re installing stucco over OSB or plywood, here’s how to create a ventilated rainscreen gap:
   Install at least one layer of WRB — housewrap, asphalt felt, or Grade D building paper — over the wall sheathing.
   Install a three-dimensional plastic drainage mat (for example, Cedar Breather) over the WRB. It’s also possible to purchase all-in-one products that marry a three-dimensional plastic mat with a WRB backing. Such products include the WaterWay rainscreen drainage mat, the Korax Stucco Rainscreen Panel, the Home Slicker Stone & Stucco rainscreen, the Mortairvent mortar deflection and ventilation system, and Delta-Dry.
   Install at least one more layer of asphalt felt or Grade D paper on top of the drainage matrix.
   Install galvanized (expanded metal) or fiberglass lath, and proceed with a standard installation of three-coat stucco.”