Apply Vertical Spray-Applied Membranes: QA and Adhesion

The checklist

Pre-Application Verification

1. 1Confirm the system is spray-applied (not brush/roller liquid-applied); record product name, data sheet, and approvals; obtain supervisor sign-off.
2. 2Inspect vertical substrate soundness; remove laitance and weak material; verify clean, dry, dust-free surface; photo evidence with scale and date.
3. 3Measure substrate moisture with a calibrated meter; acceptance: ≤5% w/w or per approved project specifications; log readings and device serial number.
4. 4Record environmental conditions: 5–35 °C, RH ≤85%, substrate ≥3 °C above dew point; use calibrated psychrometer; attach screen/photo evidence.
5. 5Mask adjacent finishes and install ground-level catch boards/tarps within 0.5 m of wall; photo coverage before spraying.

Equipment and Spray Setup

1. 6Verify spray equipment calibration per manufacturer: ratio within ±2% of target; record pressures/temperatures; capture system printout or dashboard photo.
2. 7Prepare materials per data sheet; record batch/lot numbers and expiry; retain labels and delivery dockets as evidence.
3. 8Create a 0.5 m² vertical mock-up; confirm finish, coverage, and rebound management; obtain client/consultant approval signature and photos.
4. 9Set spray fan, tip, and standoff distance (300–450 mm or per manufacturer); verify uniform pattern on test card; photo pattern.

Coverage and Rebound Control

1. 10Apply in multiple light passes with 50% overlap to avoid sagging; no visible runs; supervisor visual check recorded with photos.
2. 11Measure wet film thickness (WFT) using a comb gauge: ≥5 locations per 10 m²; acceptance: average at target, none below minimum.
3. 12After cure, measure dry film thickness (DFT) by ultrasonic gauge on a 1 m grid; acceptance: ≥95% area within −10%/+15% of target; no point below minimum.
4. 13Collect rebound after each lift; weigh and log mass; acceptance: ≤10% by mass relative to sprayed output; photo bagged waste.
5. 14Prohibit reuse of rebound; dispose per site environmental plan; attach disposal ticket and supervisor confirmation.
6. 15Detail corners and penetrations with fillets or sealant per system; minimum 10 mm radius; photo continuous coverage without pinholes.

Adhesion and Curing Verification

1. 16Conduct pull-off adhesion tests with 50 mm dollies: min 5 per 100 m²; acceptance: ≥1.0 MPa or per approved project specifications and authority requirements; record values and failure modes.
2. 17Confirm cure readiness: tack-free check and hardness per data sheet; record time-since-application and measured hardness values.
3. 18Perform holiday detection on cured membrane where applicable using high-voltage spark testing; acceptance: zero holidays; mark, repair, and retest; photo evidence.

Protection and Detailing

1. 19Install mechanical protection (e.g., 3–6 mm boards or 300 g/m² geotextile) before backfilling or adjacent works; photo full-height coverage.
2. 20Verify UV stability; if non-UV-stable, overcoat or conceal within manufacturer’s stated window; record dates/times and photos.
3. 21Coordinate terminations with termination bars, sealant, or flashings; continuous bead and fixings at specified centres; photo close-ups.

Documentation and Handover

1. 22Confirm exclusion of brush/roller liquid-applied systems in this work package; upload supervisor statement and product installation evidence.
2. 23Final inspection on 1 m grid: recheck DFT at random points, verify repairs closed; attach as-built photos with measuring scale.
3. 24Compile dossier: data sheets, lot numbers, calibration records, WFT/DFT logs, adhesion results, repairs; obtain stakeholder sign-offs.
4. 25Record safety controls during spraying: ventilation, PPE, and ignition control; evidence: toolbox talk record and daily checklist with signatures.

Preview the printable checklist

Preview page one below. Open the image or download the PDF for all pages.

At a glance

• Deliver consistent, verifiable vertical membrane coverage using objective controls: calibrated spray setup, wet/dry film gauges, systematic grid checks, and photographic evidence. Reduce variability by using approved mock-ups, controlled passes, and acceptance tolerances tied to the manufacturer’s target thickness across edges, corners, and penetrations.
• Contain and document rebound on vertical surfaces to prevent contamination, slips, and re-entrainment of defective material. Use catch boards, floor tarps, and timed cleanup intervals with mass-based waste logs. Strengthen discipline by prohibiting rebound reuse and recording waste tickets for transparent environmental reporting.
• Validate adhesion and durability with scheduled pull-off testing, cure readiness checks, and holiday detection where applicable. Protect the finished surface with boards or geotextile, confirm UV stability or overcoat timelines, and complete as-built records to support warranty, backfilling, and subsequent trades without damaging the membrane.
• Interactive online checklist with tick, comment, and export features secured by QR code.

How to Use This Interactive Checklist

1. Preparation: Review the approved data sheet, verify vertical scope only, assemble gauges (WFT/DFT), pull-off kit, PPE, masking, and calibrated environmental instruments.
2. Set up: Create or confirm an approved mock-up, calibrate equipment, and stage catch boards and protection before opening materials.
3. Using the Interactive Checklist: Start interactive mode, tick items in sequence, and add time-stamped comments with photos, readings, and lot numbers.
4. Evidence capture: Attach measurement logs, equipment calibration records, and close-up photos showing scales and defect repairs with retest results.
5. Export and share: Generate an export as PDF/Excel for review meetings and upload to the project document system.
6. Sign-off: Collect digital signatures from contractor, consultant, and client; archive the QR-authenticated record for compliance and warranty.

Achieving Uniform Vertical Coverage Without Runs or Gaps

Uniform coverage on vertical surfaces depends on controlled equipment setup, pass strategy, and continuous verification. Start with a properly approved mock-up that demonstrates spray angle, standoff distance, and 50% overlap. Use multiple light passes to build thickness and avoid sagging, keeping the gun perpendicular to the wall and moving at a steady pace. Measure wet film thickness frequently with a comb gauge to catch under-coverage early, then verify dry film thickness using an ultrasonic gauge after cure. Grid-based checks are particularly effective on tall elevations—sample every metre both horizontally and vertically. Corners, edges, and penetrations are frequent weak points; add fillets and change-of-plane reinforcement as prescribed, and photograph these locations with a ruler for scale. Acceptance should be tied to the target thickness in the data sheet, with most of the area falling within a tight tolerance band and no spot below minimum. Document all findings to build a defensible quality record.

• Build in light passes to prevent sags and runs.
• Use grid-based WFT/DFT checks on tall elevations.
• Photograph corners and penetrations with scale.
• Tie acceptance to manufacturer target thickness.
• Capture readings and signatures immediately.

Managing Rebound and Overspray on Vertical Works

Rebound is an inevitable by-product in many spray processes, especially cementitious or high-build elastomeric systems, and must be controlled to prevent defects and waste. Install catch boards close to the wall and protect adjacent floors and finishes with tarps before spraying. Schedule cleanup after each lift so rebound does not embed into fresh material or migrate into joints. Weigh and log collected rebound to quantify waste; set a reasonable project limit so trends can be addressed quickly. Never reintroduce rebound into the work—it carries oversized particles and contaminants that compromise adhesion and continuity. Overspray drift is mitigated by stable gun positioning, wind screens where practical, and controlling atomisation per the data sheet. Maintain housekeeping to keep walking routes safe and to avoid tracking material onto finished surfaces. Thorough documentation—including photos of protection measures and disposal tickets—supports environmental compliance and helps validate workmanship during handover.

• Install catch boards and floor tarps early.
• Clean up rebound after each lift.
• Log rebound mass and disposal tickets.
• Do not reuse rebound under any circumstance.
• Control atomisation to limit overspray.

Adhesion, Curing, and Protection to Maintain Performance

Adhesion is the backbone of sprayed membranes on vertical substrates. Plan pull-off tests at agreed frequencies and report both values and failure modes, noting whether failures occur at the interface or within the substrate. Confirm cure readiness through tack-free checks and hardness values defined by the manufacturer; only then proceed to holiday detection where applicable. Address defects immediately with documented repairs and retesting. Once acceptance is achieved, install mechanical protection—boards or geotextiles—before backfilling or exposing the surface to trade traffic. If the system is not UV-stable, overcoat or conceal within the stated window to prevent degradation. Pay special attention to terminations and penetrations, ensuring sealed, continuous transitions to adjoining systems. Keep every step evidence-based: attach calibrated instrument records, photos with scales, and time stamps. This approach aligns with approved project specifications and authority requirements, safeguarding durability and enabling clean, dispute-free handover.

• Report adhesion values and failure modes.
• Verify cure before holiday detection.
• Protect membranes before backfilling or traffic.
• Overcoat non-UV-stable systems on time.
• Document repairs and retests thoroughly.