Code-Compliant Grade D Paper for Stucco: What It Is and Why It Matters
Written by Stucco Champions — your trusted exterior stucco specialists in Southern California.
When it comes to stucco, success starts before the first coat is applied. One of the most overlooked — yet critical — materials in a stucco system is Grade D building paper.
This moisture-resistant barrier plays a key role in protecting your home or building from water damage and mold. And when installed correctly, it helps your stucco last decades longer.
What Is Grade D Paper?
Grade D paper is a water-resistant building paper made from kraft paper coated with asphalt. It’s typically used behind stucco systems as the first line of defense between the framing and the outer layers.
It acts as a moisture barrier, allowing vapor to escape while preventing liquid water from soaking into the structure.
Why “Code-Compliant” Matters
Not all building paper is approved for stucco use. Local and state codes — including California Building Code Section 2510.6 — require specific performance standards.
To be considered code-compliant, Grade D paper must:
-
Meet minimum water resistance
-
Allow breathability (perm rating)
-
Be used in two layers (or one layer over a foam or drainage mat)
-
Be installed with proper overlap and flashing
At Stucco Champions, we only use tested and approved materials that meet or exceed ASTM and CBC guidelines.
Where It Fits in the Stucco System
Grade D paper goes on before the metal lath and after the framing or sheathing. The order of operations typically looks like this:
-
Sheathing (plywood, OSB, etc.)
-
First layer of Grade D paper
-
Second layer of Grade D paper (overlaps for added protection)
-
Metal lath installation
-
Stucco scratch coat
Each layer is flashed and sealed properly to direct water out and away from the structure.
Benefits of Using Proper Grade D Paper
-
Prevents water intrusion
-
Allows walls to breathe — reducing mold risk
-
Improves stucco adhesion by creating a dry surface
-
Protects wood framing and insulation from long-term damage
-
Ensures code compliance to avoid failed inspections
Stucco Champions Tip: We never reuse or layer incompatible materials. Moisture management starts with doing it right the first time.
Common Misconceptions
Can I just use house wrap instead of Grade D paper?
Not for three-coat stucco. Most house wraps don’t meet fire and moisture codes for stucco applications in California.
Is one layer enough?
In most residential builds, two layers are required by code to protect the wall and control moisture movement.
Final Thoughts
Code-compliant Grade D paper may not be visible once the job is done — but it’s one of the most important parts of a proper stucco system. It protects your investment from water damage and sets the stage for a lasting finish.
At Stucco Champions, we always install the correct materials in the correct order to give our clients peace of mind and long-term value.
Ready to Simplify Your Stucco Work?
Contact Stucco Champions today for a free consultation!
Visit us at Stucco Champions for helpful resources and to learn more about our services.