---
title: "Step 5: Scupper Sequencing and Membrane Integration"
url: https://stacklist.com/card/a58ef693-3f47-458b-9fb7-94122a5e1402
stack: https://stacklist.com/c/business/stack/2d67154e-83fe-4367-99db-e7e4088ce2f9
summary: "Scupper sequencing and membrane integration is a critical balcony waterproofing detail that requires framing the opening first, installing the scupper sleeve before the membrane, and shingling the membrane into the throat to prevent leaks. The correct sequence involves setting the scupper body, priming the flange, lapping membrane over it by minimum 2 inches, and ensuring the cut edge remains inside the throat rather than exposed."
tags: "scupper-sequencing, membrane-integration, balcony-waterproofing, construction-detail, flashing-installation"
key_entities: "S60 membrane (technology), SP1 primer (technology), scupper throat clearance (concept), membrane shingling (concept)"
classification: "tutorial"
content_hash: "sha256:326d3cb0fa52deddc93cf8789e9a89e28599f65c8a91b16ea01bd1ef250d540d"
acp_version: "0.2"
token_counts_approximate: 581
visibility: public
agent_accessible: true
status: "final"
---

# Step 5: Scupper Sequencing and Membrane Integration

Step 5: Scupper Sequencing and Membrane
Integration 
Overview 
Scuppers are the most commonly botched detail in balcony waterproofing. The correct sequence is:
frame the scupper opening, set the scupper sleeve before membrane, then shingle the membrane into
the scupper throat. Installing the membrane first and then cutting for the scupper almost always results
in an exposed edge and a leak path. 
Correct Sequence 
1. Frame first: Scupper opening is framed and dimensioned per drawings before any waterproofing
begins. 
2. Set the scupper sleeve: Install the scupper body (sleeve or liner) and mechanically fasten the flange
to the deck framing or curb. The flange must be flat and fully seated. 
3. Prime the flange: Apply SP1 primer over the scupper flange and minimum 6 in. onto the
surrounding deck surface. 
4. Membrane over flange: Run the S60 membrane so it laps over the scupper flange on all sides by
minimum 2 in. Cut the membrane at the inside edge of the scupper throat (not at the outside edge
of the flange). 
5. Shingle into the throat: The membrane should shingle into the scupper opening so the cut edge is
inside the throat, not exposed on the exterior. This prevents water from wicking under the
membrane edge. 
6. Press the flange membrane: Use a seam roller to press the membrane firmly onto the scupper
flange on all four sides. No lifted edges. 
Scupper Throat Clearance 
After membrane is installed, confirm the scupper throat is clear of obstructions and debris. 
Minimum throat dimension per design drawings (typically 3 in. x 4 in. minimum for residential
balconies). 
Confirm the bottom of the scupper throat is at or below the finished topping surface elevation. 
Inspection Checklist 
8/8/26, 12:46 AM Step 5: Scupper Sequencing and Membrane Integration 
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[ ] Scupper set before membrane (not cut in after) 
[ ] Flange fully flat and mechanically fastened 
[ ] SP1 primer on flange and 6 in. surround 
[ ] Membrane laps over flange minimum 2 in. on all sides 
[ ] Membrane cut edge is inside the scupper throat 
[ ] Seam roller used on all flange edges 
[ ] Throat clear and at correct elevation 
[ ] Inspector sign-off: ______________ Date: ______________ 
8/8/26, 12:46 AM Step 5: Scupper Sequencing and Membrane Integration 
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