Cladding Key Specs
| Material | Critical Installation Rules |
|---|
| Vinyl siding | 6 mm expansion gap (10 mm cold); centre nail in slot; 1 mm nail clearance; lock with click |
| Fibre cement | Back-prime ALL planks; galv./stainless ring-shank nails, flush; 3 mm butt gap; 150 mm grade clearance |
| Metal panel | Fixed clip + sliding clips; expansion joints 6 m (steel) / 4.5 m (aluminum); separate dissimilar metals |
| EIFS | Drainage type ONLY; certified installer; expansion joints 5.4 m max; impact mesh at grade |
| Masonry veneer | Weeps every 800 mm; expansion joints 6 m; soft joint below shelf angles; concave tooling |
Rain screen assembly always: cladding → 19 mm cavity → WRB → sheathing → insulation → VR
Sealant Joint Design
| Type | Movement | Paintable | Best For |
|---|
| Silicone | ±50% | No | Glass, metal, masonry |
| Polyurethane | ±25–50% | Yes | Masonry, wood, fibre cement |
| Hybrid (STPE) | ±25–50% | Yes | General exterior (HCMI default) |
| Acrylic latex | ±7.5% | Yes | Protected trim joints only |
- 2:1 rule: width : depth (12 mm wide = 6 mm deep)
- Backer rod 25–50% larger than joint; controls depth & prevents 3-sided bond
- Tool within 5–10 min; concave profile; no wet-finger on structural joints
- Min. joint width 6 mm; max. practical 50 mm
Soffit & Fascia
- Ventilation NFA: 1/300 of ceiling area (OBC 9.19.1); 60% intake / 40% exhaust
- Vented soffit: 7–9 cm² NFA per 30 cm; calculate before ordering
- Drip edge laps over fascia face min. 15 mm
- Ice & water shield extends min. 900 mm from eave edge
- F-channel at wall; under-sill trim at fascia
Fascia Materials
| Material | HCMI Use |
|---|
| Cellular PVC | Default — rot-proof, paintable; max span 600 mm |
| Fibre cement | Non-combustible assemblies (OBC 3.2.2) |
| Aluminum-wrapped wood | Standard projects; no painting |
| Cedar | Heritage restoration only; seal all 6 sides |
Exterior Painting & Coatings
| Product | Use |
|---|
| 100% acrylic latex | Wood, fibre cement, masonry — workhorse |
| Elastomeric | Masonry, stucco, EIFS — bridges cracks to 1 mm |
| Alkyd (oil) | Primer only on bare wood/metal |
| DTM acrylic | Direct-to-metal on handrails, trim, misc. |
Film Thickness
- Latex: 4–6 mils wet / 1.5–2.0 mils DFT per coat
- Elastomeric: 16–24 mils wet / 8–12 mils DFT
- Primer: 3–4 mils wet / 1.0–1.5 mils DFT
Spray tip: 0.017–0.021" latex; 0.021–0.025" elastomeric. Always spray + back-roll.
Weather Limits
| Activity | Min. Temp | Notes |
|---|
| Vinyl install | −5°C | Brittle below; increase gaps in cold |
| Exterior paint | 10°C | RH <85%; no rain 24 h; follow the shade |
| Sealant | 5°C | Dry substrate; no rain 24–48 h |
| EIFS base/finish | 5°C rising | No rain/freeze 24 h after application |
| Masonry | 5°C | CSA A371; heated enclosures below −5°C |
Ontario painting season: May–mid October. Have substrates ready by June.
Code References
- OBC Part 5: Environmental separation — WRB, air/vapour barriers, insulation
- OBC 9.19.1: Attic ventilation NFA requirements (1/300)
- OBC 3.1.5 / 3.2.2: Non-combustible construction, ACM core restrictions
- CSA A371: Masonry construction — cold-weather provisions
- ASTM C920: Elastomeric sealant standards (Class 25/50)
- CAN/ULC-S114: Non-combustibility test (fibre cement)
- O. Reg. 213/91: Fall protection, scaffolding
- O. Reg. 490/09: Silica exposure limits (0.025 mg/m³)
Safety & Critical Rules
- Working at heights: Fall protection above 3 m; Working at Heights cert required (O. Reg. 213/91).
- Silica (fibre cement): Use shears or HEPA-vacuum saw. N95 min. No dry circular saw cuts. OEL 0.025 mg/m³.
- Lead paint (pre-1978): O. Reg. 278/05 handling & disposal procedures.
- ACM panels: FR mineral core ONLY. PE core = fire hazard — prohibited >3 storeys; ban on all HCMI projects.
- 308A Sheet Metal (compulsory): Required for metal panel fabrication & custom flashing.
- EIFS installer: Must hold manufacturer certification. No cert = no warranty = no work.
- No field substitutions to envelope assembly without engineer approval.
Pro Tips
- Pre-cladding inspection: Check WRB, flashings, furring, insect screen before any cladding covers them.
- Fibre cement shear on every site — zero-dust straight cuts; saves time and lungs.
- Sealant adhesion test on actual substrate before production. Some sealants stain stone or dissolve membranes.
- Photo document all concealed layers (WRB, sill pans, flashing) before cladding closes them up.
- Scaffold tie patches: Budget a full day after scaffold removal to patch all WRB penetrations.