# Wall Assemblies - When to Use What

## Decision Logic

### Exterior Wall Selection
```
Is it in Florida coastal zone?
  YES → CMU or reinforced concrete (hurricane)
  NO → Wood frame OK

Is fire rating required?
  YES → See fire-rated assemblies below
  NO → Standard assembly OK

Is it below grade?
  YES → Concrete or CMU with waterproofing
  NO → Standard assembly
```

### Interior Wall Selection
```
Is fire rating required?
  YES → Use rated assembly (1-hr or 2-hr)
  NO → Continue...

Is it a wet area (bathroom, kitchen, laundry)?
  YES → Moisture-resistant GWB (green board) or cement board
  NO → Standard GWB

Is sound control needed?
  YES → Add insulation + staggered studs or resilient channel
  NO → Standard assembly
```

---

## Exterior Wall Types

### Type EW-1: Wood Frame (Standard Residential)
**Use when:** Non-coastal, typical residential
```
Exterior to Interior:
- Siding (lap, board & batten, or stucco)
- Weather barrier (Tyvek, felt paper)
- 1/2" plywood or OSB sheathing
- 2x4 or 2x6 studs @ 16" O.C.
- R-13 or R-19 batt insulation
- 6 mil vapor barrier (check climate zone)
- 1/2" GWB
```
**R-Value:** R-13 to R-19
**Thickness:** 4-1/2" to 6-1/2" (plus finishes)

### Type EW-2: CMU (Florida Coastal / Hurricane Zone)
**Use when:** Coastal Florida, high wind areas, commercial
```
Exterior to Interior:
- Stucco or paint (elastomeric)
- 8" CMU with vertical rebar @ 32" O.C.
- Horizontal bond beam every 4'
- Filled cells at rebar locations
- Furring strips or hat channel
- R-4 rigid insulation (or spray foam)
- 1/2" GWB
```
**R-Value:** R-4 to R-8 (with insulation)
**Thickness:** 8" to 10"

### Type EW-3: CMU with Cavity (Enhanced)
**Use when:** Better insulation needed, commercial
```
Exterior to Interior:
- Stucco or masonry veneer
- 4" CMU or brick
- 2" air cavity with weeps
- Weather barrier
- 2" rigid insulation
- 8" CMU backup
- 1/2" GWB on furring
```
**R-Value:** R-10 to R-15
**Thickness:** 14" to 16"

### Type EW-4: Metal Stud (Commercial)
**Use when:** Commercial, multi-story, non-load bearing
```
Exterior to Interior:
- EIFS, metal panel, or rain screen
- Weather barrier
- 5/8" exterior sheathing
- 6" metal studs @ 16" O.C.
- R-19 batt insulation
- Vapor barrier (climate dependent)
- 5/8" Type X GWB
```
**R-Value:** R-19
**Thickness:** 7" (plus finishes)

---

## Interior Wall Types

### Type IW-1: Standard Interior
**Use when:** Non-rated, typical room separation
```
- 1/2" GWB
- 2x4 studs @ 16" O.C.
- 1/2" GWB
```
**Thickness:** 4-1/2"
**STC Rating:** ~33

### Type IW-2: Sound-Rated Interior
**Use when:** Bedrooms, between units, noise control
```
- 1/2" GWB
- Resilient channel
- 2x4 studs @ 16" O.C.
- R-11 batt insulation (unfaced)
- 1/2" GWB
```
**Thickness:** 4-1/2"
**STC Rating:** ~45

### Type IW-3: 1-Hour Fire-Rated
**Use when:** Corridors, occupancy separation, garage to house
```
- 5/8" Type X GWB
- 2x4 studs @ 16" O.C.
- R-11 batt insulation (optional)
- 5/8" Type X GWB
```
**Thickness:** 4-5/8"
**Fire Rating:** 1 hour
**STC Rating:** ~40

### Type IW-4: 2-Hour Fire-Rated
**Use when:** Stair enclosures (4+ stories), major occupancy separation
```
- (2) layers 5/8" Type X GWB
- 2x4 studs @ 16" O.C.
- R-11 batt insulation (optional)
- (2) layers 5/8" Type X GWB
```
**Thickness:** 6"
**Fire Rating:** 2 hour

### Type IW-5: Shaft Wall
**Use when:** Elevator shafts, mechanical shafts, stair shafts
```
- 1" shaft liner panel (fire side)
- 2-1/2" C-H studs @ 24" O.C.
- 5/8" Type X GWB (room side)
```
**Thickness:** 4"
**Fire Rating:** 2 hour
**Note:** One-side construction for shafts

### Type IW-6: Demising Wall (Between Units)
**Use when:** Separating dwelling units, condo/apartment
```
- 5/8" Type X GWB
- 2x4 studs @ 16" O.C.
- R-11 batt insulation
- 1" air gap
- 2x4 studs @ 16" O.C.
- R-11 batt insulation
- 5/8" Type X GWB
```
**Thickness:** 10"
**Fire Rating:** 1 hour
**STC Rating:** ~55-60

---

## Wet Area Walls

### Type WW-1: Bathroom/Kitchen (Standard)
```
- Moisture-resistant GWB (green board)
- 2x4 studs @ 16" O.C.
- Moisture-resistant GWB
```
**Note:** Green board OK for areas NOT directly in shower/tub

### Type WW-2: Shower/Tub Surround
```
- Cement board (Durock, Hardiebacker)
- Waterproof membrane
- 2x4 studs @ 16" O.C.
- Moisture-resistant GWB (opposite side)
```
**Note:** NEVER use paper-faced GWB in shower

### Type WW-3: Commercial Restroom
```
- Cement board or fiber cement
- 2x4 or metal studs @ 16" O.C.
- Moisture-resistant GWB
```

---

## Special Conditions

### Furring at Concrete/CMU
When attaching GWB to concrete or CMU:
```
Option 1: Hat Channel
- 7/8" hat channel @ 16" O.C.
- 1/2" GWB
Total: 1-3/8" added thickness

Option 2: Wood Furring
- 1x3 furring @ 16" O.C.
- 1/2" GWB
Total: 1-1/4" added thickness

Option 3: Z-Furring with Insulation
- Z-furring with 1-1/2" rigid insulation
- 1/2" GWB
Total: 2" added thickness
```

### Plumbing Walls
Walls containing plumbing need more depth:
- 2x4 wall: Small drain lines only
- 2x6 wall: Up to 3" drain lines
- 2x8 wall: 4" drain lines (toilets)
- Staggered stud wall: Flexible for pipes

---

## Wall Type Schedule Format

When creating wall schedules, include:
| Type | Description | Thickness | Fire Rating | STC | Notes |
|------|-------------|-----------|-------------|-----|-------|
| EW-1 | Ext Wood Frame | 6" | N/A | 40 | Typical residential |
| IW-1 | Int Standard | 4-1/2" | N/A | 33 | Non-rated |
| IW-3 | Int 1-HR | 4-5/8" | 1 HR | 40 | Corridor walls |
