---
title: "Check 3: S60 Membrane Seams and Lap Inspection"
url: https://stacklist.com/card/d2f91416-6bbe-41bd-a56e-3291872c51fd
stack: https://stacklist.com/c/business/stack/8b50c285-c1e7-42de-ac4c-343659a54e54
summary: "Check 3: S60 Membrane Seams and Lap Inspection is a quality control checklist for roofing membrane installation that verifies roll sequencing, seam laps, membrane condition, and drain integration before drainage mat placement. All inspection items must pass and be signed off by an inspector before proceeding to the next construction phase."
tags: "membrane-inspection, s60-roofing, seam-laps, quality-control, drainage-mat, hold-point, construction-checklist"
key_entities: "S60 Membrane (technology), Roll Sequencing (concept), Seam Laps (concept), Drain Integration (concept), Shingle Effect (concept), Fishmouth (concept)"
classification: "checklist"
content_hash: "sha256:aff90ea2824e9be0b5928d7fb676ad58db90a499ac4c75d6c2fca12fd76caa42"
acp_version: "0.2"
token_counts_approximate: 472
visibility: public
agent_accessible: true
status: "final"
---

# Check 3: S60 Membrane Seams and Lap Inspection

Check 3: S60 Membrane Seams and Lap Inspection 
Hold Point: All seams must pass before drainage mat is placed. 
Roll Sequencing 
[ ] Membrane rolls are installed starting from the low point and working toward the high point
(shingle effect) 
[ ] Roll direction is parallel to drain, sequencing toward drain 
[ ] No rolls installed against the drainage slope 
[ ] Adjacent rolls are offset so end laps do not align (staggered T-joints) 
Seam Laps 
[ ] All side laps are a minimum of 3 in. 
[ ] All end laps are a minimum of 3 in. 
[ ] Lap lines are consistent and marked: no guessing at coverage 
[ ] All laps are fully adhered: no bridging, tenting, or open edges 
[ ] No fishmouths at any lap edge: all wrinkles are cut, patched, and re-lapped 
Membrane Condition 
[ ] No punctures, tears, or cuts in the field membrane 
[ ] No embedded debris under the membrane 
[ ] Membrane is fully seated to the primed substrate: no air pockets or bubbles 
[ ] All cut edges at drains and penetrations are sealed 
Drain Integration 
[ ] Membrane is cut to the inside edge of the drain clamping ring 
[ ] Membrane is fully adhered into the drain bowl: no lifting at the perimeter 
[ ] Drain clamping ring is installed over the membrane and torqued to spec 
[ ] No membrane material blocking the drain throat 
8/8/26, 12:57 AM Check 3: S60 Membrane Seams and Lap Inspection 
https://md2pdf.netlify.app 1/2 

Inspector Sign-Off 
Item Pass Inspector Date 
Roll sequencing correct [ ] __________ __________ 
All laps 3 in. min, fully adhered [ ] __________ __________ 
No fishmouths or open edges [ ] __________ __________ 
No punctures or tears in field [ ] __________ __________ 
Drain integration complete [ ] __________ __________ 
Do not proceed to drainage mat until all seam checks are signed off. 
8/8/26, 12:57 AM Check 3: S60 Membrane Seams and Lap Inspection 
https://md2pdf.netlify.app 2/2