ETICS Steps: EPS & MW
0) Pre-checks & design
- Heat-loss/U-value calc, fire strategy (fire barriers, cavity closers), wind-zone & anchor design, movement joint layout.
- Confirm substrate type, flatness (±3–5 mm/2 m straightedge), moisture (< prescribed limits), and compatibility.
1) Substrate preparation
- Clean, sound, dry surface; remove weak render/paint, algae, oils.
- Level high spots; fill depressions; rasp if needed.
- Prime per system (especially on dense/absorbent substrates).
- Install/verify damp-proof courses and flashing continuity.
2) Starter/base profile & accessories
- Fix starter track (aluminium/PVC) level at datum; add drip edge.
- Fit corner beads, stop beads, movement-joint profiles, sill end-caps, window reveal beads with mesh wings.
3) Adhesive application
- Mix system adhesive per data sheet (pot life, temp limits).
- EPS: typically perimeter + dabs or full-coverage (rasped board backs for grip).
- Mineral Wool: prefer full-surface buttering (or lamella ribbed) for pull-out strength and airtightness.
- Maintain adhesive coverage ≥ 40% (dabs) or as specified (often 60–100%); avoid adhesive on board edges.
4) Board installation
- Stagger vertical joints, break bond at corners (“L” bonds).
- Keep tight joints (≤2 mm); infill gaps with slivers of insulation (not foam unless specified).
- Mineral Wool: keep fiber orientation per product (lamella vs slab); protect from rain.
- Avoid continuous vertical joints over openings; align reveals with preformed beads.
5) Fire barriers & special zones (code-driven)
- Install mineral wool fire breaks at floor lines, around openings, and at compartment lines where required (even in EPS façades).
- High-impact zones (ground floor/corners): specify high-impact mesh or additional base-coat thickness.
6) Mechanical fixings (anchors)
- After adhesive cure (or wet-on-wet if allowed), drill and fix per anchor plan (type, length, embedment).
- Typical patterns: 6–8/m² (depends on wind zone/substrate/system).
- Set heads flush or recessed; cap with adhesive; avoid thermal bridges.
- Pull-out tests on site where required.
7) Rasping & levelling
- EPS: rasp plane after curing to remove steps; vacuum dust.
- Mineral Wool: light plane only if specified; keep surface true.
8) Base coat & reinforcement mesh
- Apply first base coat; embed alkali-resistant mesh with 100 mm overlaps (≥150 mm at corners/returns).
- Diagonal mesh patches at all window/door corners.
- Add second pass to fully cover mesh (no print-through).
- Maintain specified thickness (often ~3–5 mm total; check system).
9) Primers & finishes
- Respect curing/drying times; protect from rain/sun/wind.
- Apply primer tinted to finish where required.
- Apply finish coat: thin-coat acrylic/silicate/siloxane/mineral or decorative options (stone dash, etc.).
- Observe temp/humidity/wind limits; maintain wet edges to avoid shading.
10) Sealing & flashings
- Install/verify through-wall flashings, counter-flashings, parapet caps.
- Seal junctions to windows/doors with system sealants (backer rod + elastic sealant).
- Complete drips at sills, balconies, and base of façade; ensure water can exit.
11) Penetrations & interfaces
- Use preformed collars/boots for pipes, rails, brackets; reinforce with mesh patches.
- Isolate fixtures with thermal pads to reduce cold bridges; seal all penetrations.
12) QA/commissioning
- Document batch numbers, weather logs, substrate moisture checks, anchor counts, mesh overlap photos.
- Final inspection for flatness, mesh print-through, shade uniformity, sealant continuity, and water-shedding details.
- Hand over maintenance guide (washing, inspections, repaint cycles).
EPS vs Mineral Wool: quick differences within the same steps
- Adhesive & fixing: MW prefers higher adhesive coverage and more robust anchors; EPS easier to rasp/plane.
- Fire: MW is A1 non-combustible; EPS façades require MW fire barriers per design.
- Moisture/vapor: MW is more vapor-open; manage interior vapor control if the wall needs outward drying.
- Handling: EPS lighter/faster; MW heavier—plan logistics and weather protection.
Common mistakes to avoid
- Skipping system components (mixing brands voids certification).
- Poor mesh detailing at openings and edges.
- Missing/short overlaps and movement joints.
- Installing in wrong weather window (blistering/shading).
- No drip edges/weep → staining and moisture traps.
- Inadequate anchor embedment or wrong type for substrate.
Maintenance (owner tips)
- Visual check annually (cracks, sealants, staining).
- Gentle wash as needed; avoid pressure-washing finishes not rated for it.
- Repair chips early; maintain sealants and flashings to keep water out.
