PC-02
Stucco Flashing
The screed line that lets a stucco wall drain and breathe.
Stucco is a hard, crack-prone finish over a soft, moisture-sensitive wall assembly. Weep screed is the detail that keeps those two things from becoming a problem: a clean termination edge at the base of the wall that lets trapped moisture out.
Weep screed (sometimes called a foundation screed) is installed at the bottom of every stucco wall, and again anywhere the stucco needs a clean, controlled edge, around windows, at control joints, and where stucco meets a different material. It gives the plasterer a straight line to work to and gives the wall assembly a way to drain and dry.
We cut screed and casing bead to your run lengths and can supply the control-joint profiles that break a large stucco field into smaller panels, which is what actually controls where hairline cracking happens.
There's a real difference between three-coat stucco and EIFS (exterior insulation and finish systems), and it shows up in the screed detail. Three-coat stucco is applied directly over building paper and lath on a scratch and brown coat before the finish goes on, so the screed has to manage moisture coming through a fairly permeable assembly. EIFS builds the stucco look over rigid foam insulation, which changes drainage requirements and often calls for a different screed profile with a drainage cavity behind it. Tell us which system you're running and we'll cut the right profile.
Alberta stucco takes a beating from freeze-thaw cycling and big daily temperature swings, especially on south and west-facing walls that heat up fast in winter sun and then refreeze overnight. That thermal cycling is a big part of why hairline cracking shows up even on well-built walls, and it's also why a properly detailed weep screed matters. If moisture can't get out at the base of the wall, it sits behind the stucco through repeated freeze cycles and the cracking gets worse, not better.
Screed installation happens early, usually right after the sheathing and building paper are on and before lath goes up, so timing with your other trades matters. We can turn most orders around fast enough to keep a stucco crew from waiting on material, but a call a few days ahead of when you need it on site gives us room to confirm the exact leg height and any control-joint layout with you before we cut.
Footage & Piece Calculator
Enter the total run length you need to cover. We'll estimate how many stock-length pieces to order, with a waste allowance for laps and cuts.
Estimate
4
pieces of 10 ft stock
40 ft
total footage to order
Estimate only. Call the shop to confirm before ordering.
Spec Sheet
What You're Ordering
- Materials
- Galvanized steel, or paper-backed expanded weep screed on request
- Leg height
- Cut to whatever your detail calls for, just tell us the height
- Also stocked/cut
- Control joints, casing bead, and stucco mouldings (see our full colour and product line)
- Clearance
- We cut to your spec, so confirm minimum height above grade/paving with your building code before ordering
Questions
Stucco Flashing FAQ
What's the difference between weep screed and a control joint? +
Weep screed terminates the stucco at the bottom of the wall and lets moisture drain out. A control joint is a break placed within the stucco field itself, so cracking happens at a controlled line instead of randomly across the wall.
How much clearance do I need above grade? +
That's set by your local building code and varies by jurisdiction. As a rule of thumb, keep stucco (and the screed) well clear of soil and paving. Check with your inspector before final grading.
Can I get screed in a colour instead of mill finish? +
Yes, though most weep screed ends up covered by grade or landscaping. Mill or galvanized is standard unless you specifically need it painted.
Do you cut casing bead too? +
Yes. Casing bead for stucco terminations at windows, doors and dissimilar materials is cut alongside your screed order.
What length do pieces come in? +
We cut to your run length rather than a fixed stock size, so waste and extra field joints are minimized.
When during the build should screed go on? +
Right after sheathing and building paper, before lath is installed. Getting it on early gives the plasterer a clean, straight edge to work from and avoids holding up the stucco crew.
Does the screed itself need weep holes or perforations? +
Most weep screed profiles have a perforated or expanded section built in specifically to let moisture drain and let the wall assembly breathe. We can match the profile to what your building envelope design calls for.
Do you supply screed for both new builds and repairs? +
Yes. Repair jobs are common, especially where an original screed was set too low, left without proper clearance above grade, or has corroded over time. We'll cut a replacement run to match your existing wall detail.
Can you match an unusual or older screed profile? +
Bring a sample from the existing wall and we'll measure and match it on our brake. Older buildings sometimes used profiles that aren't common anymore, and that's exactly the kind of job our shop is set up to run.
Also See
