Written by Stucco Champions — Southern California’s Authority on Exterior Plastering.

Installing Weep Screed Around Stairs: A Comprehensive Guide to Stepped Foundations

One of the most complex details in stucco installation is navigating a stepped foundation or staircase. Unlike a flat wall where the weep screed runs in a straight horizontal line, stairs require the flashing to "step" up and down with the concrete.

If done incorrectly, water becomes trapped at the 90-degree corners, rotting the stringers and framing behind the wall. This guide outlines the precise geometry and cutting techniques required to maintain a continuous drainage plane on uneven terrain.

1. The Geometry of the "Step"

You cannot install a single piece of metal diagonally. You must create a series of 90-degree turns that mirror the stairs.

The Components:

1. Horizontal Runs: These act as the traditional drain, sitting 2 inches above the tread (paving).

2. Vertical Risers: These connect the horizontal pieces. While they don't actively drain water, they provide the necessary depth gauge (7/8") and separation from the framing.

2. Preparation: The 2-Inch Rule

Code requires a 2-inch clearance above paved surfaces (concrete stairs) to prevent moisture wicking.

The Jig Method: Cut two small blocks of wood exactly 2 inches high. Use these as spacers on every stair tread. Rest the weep screed on these blocks to guarantee a perfect code-compliant gap without measuring every single time.

3. Installation Protocol

Precision cutting is mandatory. You will need tin snips (aviation snips) and a speed square.

Step A: The Horizontal Treads

Install all horizontal pieces first.

Measurement: Measure the length of the tread. Cut the screed to this exact length plus an additional 1/2 inch on the "uphill" side to allow for an overlap joint.

Fastening: Place the screed on your 2-inch spacer blocks. Check for level. Nail or staple the top flange into the studs/stringer.

Step B: The Vertical Risers

Once the horizontals are set, measure the vertical gap between them.

The Cut: Cut a piece of screed to fit this vertical space snugly. You may need to trim the bottom flange at a 45-degree angle to mate cleanly with the horizontal screed below it.

The Result: You should have a continuous metal line zig-zagging up the stairs.

⚠️ The Critical Detail: Lapping

This is where amateurs fail. Waterproofing must follow gravity.

When you install the building paper later, you must ensure the paper overlaps the vertical leg, and the vertical leg's flange overlaps the horizontal leg below it. If you reverse this lap, water will run behind the screed and rot the stair stringer.

4. Why Not Angle It?

We are often asked: "Can't I just run one long piece of screed diagonally up the stairs?"

The Answer: No.

1. Code Violation: It is impossible to maintain the 2-inch clearance on a diagonal. At some points, the screed will touch the concrete; at others, it will be too high.

2. Aesthetics: A diagonal line against a stepped foundation looks sloppy and unprofessional. The "Stepped" installation mirrors the architecture.

Conclusion: Precision Protects the Frame

Staircases are high-risk areas for water intrusion because water splashes off the steps onto the wall. By meticulously installing a stepped weep screed system with proper clearances, you ensure that this splash-back drains out of the wall rather than soaking into the framing.

Related Resources

Last week, we shared One Coat Stucco Weep Screed Installation. If your stairs involve foam sheathing, the attachment method changes slightly.