Surface Preparation
Updated April 01, 2026
A clean, sound substrate is essential for good adhesion and a long-lasting finish.
Important: Installation must conform to EIFS manufacturer requirements and the project’s drawings/specs.
Step 1: Verify the substrate is suitable
Before installation, confirm the surface is: - Structurally sound (no loose layers, delamination, or crumbling) - Clean (no dust, grease, chalking, or loose paint) - Dry (no ice, frost, standing water, or saturation) - Relatively flat where the moulding will sit
If the substrate is questionable, correct it before installing mouldings.
Step 2: Clean the installation area
- Brush or wipe away dust and debris.
- Remove loose paint or coatings.
- For exterior surfaces, ensure the area is free of contaminants that could block adhesion.
Avoid solvents that can harm EPS foam or interfere with coatings—follow EIFS guidance for cleaning methods.
Step 3: Repair and pre-level as needed
If your wall has dips, gaps, or damaged areas: - Repair cracks and damaged substrate per the project system. - Pre-level high/low spots where the moulding must sit flush.
Gaps behind trim can reduce bond area and lead to movement or cracking later.
Step 4: Plan water management (exterior)
For exterior applications, good detailing matters: - Ensure flashings, drip edges, and water-shedding details are correct (per project specs). - Do not create traps where water can sit behind or above trim. - Keep weep/drainage paths clear if your wall assembly requires them.
Step 5: Mark reference lines
Use a level/laser and chalk line to mark: - The top/bottom alignment line for the run - Reveal lines (if your design uses a reveal) - Corner and joint locations
This makes installation faster and keeps long runs straight.
Next step in the series
After the substrate is ready, move on to layout and dry fitting:
Measuring, Layout & Dry Fit (next post)
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