# Wall Construction Templates

### Wall Type 1: Standard Wood Frame Exterior Wall

**Basic residential construction - most common in North America**

| Layer           | Material                     | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance |
| --------------- | ---------------------------- | ------------------ | ---------------- | ---------------------------------------------- | ------------------ |
| Exterior        | Vinyl siding                 | 1/4"               | 6 mm             | k = 0.087 Btu/(hr·ft·°F)\<br>λ = 0.151 W/(m·K) | Negligible         |
| Weather barrier | Building wrap (Class III)    | -                  | -                | -                                              | -                  |
| Sheathing       | OSB                          | 7/16"              | 11 mm            | k = 0.077 Btu/(hr·ft·°F)\<br>λ = 0.133 W/(m·K) | R-0.5 (RSI-0.09)   |
| Structure       | Wood studs (16" OC)          | 5-1/2" (2x6)       | 140 mm           | k = 0.080 Btu/(hr·ft·°F)\<br>λ = 0.138 W/(m·K) | R-6.9 (RSI-1.21)   |
| Insulation      | Fiberglass batt              | 5-1/2"             | 140 mm           | k = 0.027 Btu/(hr·ft·°F)\<br>λ = 0.047 W/(m·K) | R-21 (RSI-3.7)     |
| Vapor barrier   | Polyethylene sheet (Class I) | 6 mil              | 0.15 mm          | -                                              | -                  |
| Interior        | Gypsum drywall               | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)  |

**Total Wall: 6-3/4" (171 mm) | R-21 hr·ft²·°F/Btu (RSI-3.7 m²·K/W)**

***

### Wall Type 2: Brick Veneer Wall

**Traditional masonry appearance with wood frame backup**

| Layer           | Material                              | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance   |
| --------------- | ------------------------------------- | ------------------ | ---------------- | ---------------------------------------------- | -------------------- |
| Exterior        | Brick veneer                          | 4"                 | 100 mm           | k = 0.45 Btu/(hr·ft·°F)\<br>λ = 0.78 W/(m·K)   | R-0.8 (RSI-0.14)     |
| **Air cavity**  | **Ventilated cavity with weep holes** | **1"**             | **25 mm**        | **-**                                          | **R-1.0 (RSI-0.18)** |
| Weather barrier | Building wrap (Class III)             | -                  | -                | -                                              | -                    |
| Sheathing       | OSB                                   | 7/16"              | 11 mm            | k = 0.077 Btu/(hr·ft·°F)\<br>λ = 0.133 W/(m·K) | R-0.5 (RSI-0.09)     |
| Structure       | Wood studs (16" OC)                   | 5-1/2" (2x6)       | 140 mm           | k = 0.080 Btu/(hr·ft·°F)\<br>λ = 0.138 W/(m·K) | R-6.9 (RSI-1.21)     |
| Insulation      | Fiberglass batt                       | 5-1/2"             | 140 mm           | k = 0.027 Btu/(hr·ft·°F)\<br>λ = 0.047 W/(m·K) | R-21 (RSI-3.7)       |
| Vapor retarder  | Kraft facing (Class III)              | -                  | -                | -                                              | -                    |
| Interior        | Gypsum drywall                        | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)    |

**Total Wall: 11-7/16" (290 mm) | R-23.7 hr·ft²·°F/Btu (RSI-4.2 m²·K/W)**

***

### Wall Type 3: EIFS (Exterior Insulation Finish System)

**Synthetic stucco with integrated foam insulation**

| Layer             | Material                   | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance |
| ----------------- | -------------------------- | ------------------ | ---------------- | ---------------------------------------------- | ------------------ |
| Exterior          | Acrylic finish coat        | 1/8"               | 3 mm             | k = 0.116 Btu/(hr·ft·°F)\<br>λ = 0.201 W/(m·K) | Negligible         |
| Reinforcement     | Mesh embedded in base coat | 1/8"               | 3 mm             | -                                              | -                  |
| Insulation        | EPS rigid foam board       | 2"                 | 50 mm            | k = 0.024 Btu/(hr·ft·°F)\<br>λ = 0.041 W/(m·K) | R-8 (RSI-1.4)      |
| Attachment        | Adhesive                   | -                  | -                | -                                              | -                  |
| Sheathing         | OSB                        | 7/16"              | 11 mm            | k = 0.077 Btu/(hr·ft·°F)\<br>λ = 0.133 W/(m·K) | R-0.5 (RSI-0.09)   |
| Structure         | Wood studs (16" OC)        | 5-1/2" (2x6)       | 140 mm           | k = 0.080 Btu/(hr·ft·°F)\<br>λ = 0.138 W/(m·K) | R-6.9 (RSI-1.21)   |
| Cavity insulation | Fiberglass batt            | 5-1/2"             | 140 mm           | k = 0.027 Btu/(hr·ft·°F)\<br>λ = 0.047 W/(m·K) | R-21 (RSI-3.7)     |
| Interior          | Gypsum drywall             | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)  |

**Total Wall: 8-3/4" (222 mm) | R-30 hr·ft²·°F/Btu (RSI-5.3 m²·K/W)**

***

### Wall Type 4: CMU (Concrete Masonry Unit) Wall

**Concrete block construction for commercial/industrial buildings**

| Layer             | Material                               | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance |
| ----------------- | -------------------------------------- | ------------------ | ---------------- | ---------------------------------------------- | ------------------ |
| Exterior          | Stucco finish                          | 3/4"               | 19 mm            | k = 0.41 Btu/(hr·ft·°F)\<br>λ = 0.71 W/(m·K)   | Negligible         |
| Structure         | Concrete masonry units (fully grouted) | 8"                 | 200 mm           | k = 0.58 Btu/(hr·ft·°F)\<br>λ = 1.00 W/(m·K)   | R-1.2 (RSI-0.21)   |
| Insulation        | Rigid XPS foam board                   | 2"                 | 50 mm            | k = 0.020 Btu/(hr·ft·°F)\<br>λ = 0.035 W/(m·K) | R-10 (RSI-1.76)    |
| Furring           | Steel studs (24" OC)                   | 2-1/2"             | 64 mm            | k = 314 Btu/(hr·ft·°F)\<br>λ = 543.5 W/(m·K)   | Negligible         |
| Cavity insulation | Fiberglass batt                        | 2-1/2"             | 64 mm            | k = 0.027 Btu/(hr·ft·°F)\<br>λ = 0.047 W/(m·K) | R-9 (RSI-1.6)      |
| Vapor retarder    | Polyethylene sheet (Class I)           | 6 mil              | 0.15 mm          | -                                              | -                  |
| Interior          | Gypsum drywall                         | 5/8"               | 16 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.56 (RSI-0.10)  |

**Total Wall: 14-3/8" (365 mm) | R-21 hr·ft²·°F/Btu (RSI-3.7 m²·K/W)**

***

### Wall Type 5: Metal Stud Commercial Wall

**Non-combustible construction for multi-story buildings**

| Layer           | Material                                | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance   |
| --------------- | --------------------------------------- | ------------------ | ---------------- | ---------------------------------------------- | -------------------- |
| Exterior        | Metal panel system                      | 1"                 | 25 mm            | k = 314 Btu/(hr·ft·°F)\<br>λ = 543.5 W/(m·K)   | Negligible           |
| **Air cavity**  | **Ventilated cavity with weep holes**   | **1"**             | **25 mm**        | **-**                                          | **R-1.0 (RSI-0.18)** |
| Weather barrier | Air/weather barrier membrane (Class II) | -                  | -                | -                                              | -                    |
| Sheathing       | Exterior gypsum sheathing               | 5/8"               | 16 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.56 (RSI-0.10)    |
| Structure       | Steel studs (24" OC)                    | 6"                 | 152 mm           | k = 314 Btu/(hr·ft·°F)\<br>λ = 543.5 W/(m·K)   | Thermal bridge       |
| Insulation      | Mineral wool batt                       | 6"                 | 152 mm           | k = 0.029 Btu/(hr·ft·°F)\<br>λ = 0.050 W/(m·K) | R-21 (RSI-3.7)       |
| Interior        | Type X gypsum drywall                   | 5/8"               | 16 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.56 (RSI-0.10)    |

**Total Wall: 9-1/4" (235 mm) | R-12 effective hr·ft²·°F/Btu (RSI-2.1 m²·K/W)**\*\
\*Thermal bridging through steel studs reduces cavity R-21 to approximately R-11 effective. The ventilated cavity adds R-1.0.

***

### Wall Type 6: Stone Veneer Wall

**Natural or manufactured stone facade over wood frame**

| Layer           | Material                  | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance   |
| --------------- | ------------------------- | ------------------ | ---------------- | ---------------------------------------------- | -------------------- |
| Exterior        | Manufactured stone veneer | 4"                 | 100 mm           | k = 1.50 Btu/(hr·ft·°F)\<br>λ = 2.60 W/(m·K)   | R-2.0 (RSI-0.35)     |
| **Air cavity**  | **Drainage gap**          | **3/4"**           | **19 mm**        | **-**                                          | **R-0.9 (RSI-0.16)** |
| Weather barrier | Building wrap (Class III) | -                  | -                | -                                              | -                    |
| Sheathing       | OSB                       | 1/2"               | 13 mm            | k = 0.077 Btu/(hr·ft·°F)\<br>λ = 0.133 W/(m·K) | R-0.6 (RSI-0.11)     |
| Structure       | Wood studs (16" OC)       | 5-1/2" (2x6)       | 140 mm           | k = 0.080 Btu/(hr·ft·°F)\<br>λ = 0.138 W/(m·K) | R-6.9 (RSI-1.21)     |
| Insulation      | Spray foam (closed-cell)  | 5-1/2"             | 140 mm           | k = 0.016 Btu/(hr·ft·°F)\<br>λ = 0.028 W/(m·K) | R-21 (RSI-3.7)       |
| Interior        | Gypsum drywall            | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)    |

**Total Wall: 11-3/4" (298 mm) | R-31.8 hr·ft²·°F/Btu (RSI-5.6 m²·K/W)**

***

### Wall Type 7: SIP (Structural Insulated Panel) Wall

**Factory-built panels for faster construction and superior insulation**

| Layer           | Material                      | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance   |
| --------------- | ----------------------------- | ------------------ | ---------------- | ---------------------------------------------- | -------------------- |
| Exterior        | Fiber cement siding           | 5/16"              | 8 mm             | k = 0.29 Btu/(hr·ft·°F)\<br>λ = 0.50 W/(m·K)   | Negligible           |
| **Air cavity**  | **Ventilated rainscreen gap** | **3/4"**           | **19 mm**        | **-**                                          | **R-0.9 (RSI-0.16)** |
| Weather barrier | Building wrap (Class III)     | -                  | -                | -                                              | -                    |
| Outer facing    | OSB sheathing                 | 7/16"              | 11 mm            | k = 0.077 Btu/(hr·ft·°F)\<br>λ = 0.133 W/(m·K) | R-0.5 (RSI-0.09)     |
| Core            | EPS foam insulation           | 8-1/4"             | 210 mm           | k = 0.024 Btu/(hr·ft·°F)\<br>λ = 0.041 W/(m·K) | R-33 (RSI-5.8)       |
| Inner facing    | OSB sheathing                 | 7/16"              | 11 mm            | k = 0.077 Btu/(hr·ft·°F)\<br>λ = 0.133 W/(m·K) | R-0.5 (RSI-0.09)     |
| Service cavity  | Furring strips                | 1-1/2"             | 38 mm            | -                                              | -                    |
| Interior        | Gypsum drywall                | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)    |

**Total Panel: 12-3/16" (310 mm) | R-34.9 hr·ft²·°F/Btu (RSI-6.1 m²·K/W)**

***

### Wall Type 8: ICF (Insulated Concrete Form) Wall

**Permanent foam formwork with reinforced concrete core**

| Layer            | Material                 | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance |
| ---------------- | ------------------------ | ------------------ | ---------------- | ---------------------------------------------- | ------------------ |
| Exterior         | Stucco finish            | 7/8"               | 22 mm            | k = 0.41 Btu/(hr·ft·°F)\<br>λ = 0.71 W/(m·K)   | Negligible         |
| Outer insulation | EPS foam                 | 2-5/8"             | 67 mm            | k = 0.024 Btu/(hr·ft·°F)\<br>λ = 0.041 W/(m·K) | R-10 (RSI-1.76)    |
| Structure        | Reinforced concrete core | 6"                 | 152 mm           | k = 0.90 Btu/(hr·ft·°F)\<br>λ = 1.56 W/(m·K)   | R-0.75 (RSI-0.13)  |
| Inner insulation | EPS foam                 | 2-5/8"             | 67 mm            | k = 0.024 Btu/(hr·ft·°F)\<br>λ = 0.041 W/(m·K) | R-10 (RSI-1.76)    |
| Furring          | Furring strips           | 1-1/2"             | 38 mm            | -                                              | -                  |
| Interior         | Gypsum drywall           | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)  |

**Total ICF: 14-1/4" (362 mm) | R-21 hr·ft²·°F/Btu (RSI-3.7 m²·K/W)**

***

### Wall Type 9: Interior Non-Load Bearing Partition

**Room divider walls within conditioned space**

| Layer           | Material            | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance |
| --------------- | ------------------- | ------------------ | ---------------- | ---------------------------------------------- | ------------------ |
| Interior finish | Gypsum drywall      | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)  |
| Structure       | Wood studs (16" OC) | 3-1/2" (2x4)       | 89 mm            | k = 0.080 Btu/(hr·ft·°F)\<br>λ = 0.138 W/(m·K) | Not applicable     |
| Cavity          | Empty               | -                  | -                | -                                              | Not applicable     |
| Interior finish | Gypsum drywall      | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)  |

**Total Wall: 4-1/2" (114 mm) | Not applicable (interior partition)**

***

### Wall Type 10: Double-Wall High-Performance Assembly

**Super-insulated system for passive house and net-zero buildings**

| Layer               | Material                                    | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance   |
| ------------------- | ------------------------------------------- | ------------------ | ---------------- | ---------------------------------------------- | -------------------- |
| Exterior            | Fiber cement siding                         | 5/16"              | 8 mm             | k = 0.29 Btu/(hr·ft·°F)\<br>λ = 0.50 W/(m·K)   | Negligible           |
| **Air cavity**      | **Ventilated rainscreen gap**               | **3/4"**           | **19 mm**        | **-**                                          | **R-0.9 (RSI-0.16)** |
| Weather barrier     | Building wrap (Class III)                   | -                  | -                | -                                              | -                    |
| Outer sheathing     | OSB                                         | 1/2"               | 13 mm            | k = 0.077 Btu/(hr·ft·°F)\<br>λ = 0.133 W/(m·K) | R-0.6 (RSI-0.11)     |
| Outer structure     | 2x4 wood studs (24" OC)                     | 3-1/2"             | 89 mm            | k = 0.080 Btu/(hr·ft·°F)\<br>λ = 0.138 W/(m·K) | R-4.4 (RSI-0.77)     |
| Outer insulation    | Dense-pack cellulose                        | 3-1/2"             | 89 mm            | k = 0.027 Btu/(hr·ft·°F)\<br>λ = 0.047 W/(m·K) | R-13 (RSI-2.3)       |
| Mid-layer sheathing | OSB                                         | 1/2"               | 13 mm            | k = 0.077 Btu/(hr·ft·°F)\<br>λ = 0.133 W/(m·K) | R-0.6 (RSI-0.11)     |
| Inner structure     | 2x4 wood studs (24" OC)                     | 3-1/2"             | 89 mm            | k = 0.080 Btu/(hr·ft·°F)\<br>λ = 0.138 W/(m·K) | R-4.4 (RSI-0.77)     |
| Inner insulation    | Dense-pack cellulose                        | 3-1/2"             | 89 mm            | k = 0.027 Btu/(hr·ft·°F)\<br>λ = 0.047 W/(m·K) | R-13 (RSI-2.3)       |
| Air/vapor control   | Vapor-intelligent membrane (Variable Class) | -                  | -                | -                                              | -                    |
| Interior            | Gypsum drywall                              | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)    |

**Total Wall: 13-3/16" (335 mm) | R-36.9 hr·ft²·°F/Btu (RSI-6.5 m²·K/W)**

***

### Wall Type 11: The "Institutional Wall" (500-Year Wall)

**Maximum durability for museums, libraries, and heritage buildings**

| Layer           | Material                         | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance   |
| --------------- | -------------------------------- | ------------------ | ---------------- | ---------------------------------------------- | -------------------- |
| Exterior        | Stone cladding                   | 2"                 | 50 mm            | k = 1.50 Btu/(hr·ft·°F)\<br>λ = 2.60 W/(m·K)   | R-1.0 (RSI-0.18)     |
| **Air cavity**  | **Ventilated air space**         | **1"**             | **25 mm**        | **-**                                          | **R-1.0 (RSI-0.18)** |
| Thermal control | Rigid mineral wool               | 4"                 | 100 mm           | k = 0.025 Btu/(hr·ft·°F)\<br>λ = 0.043 W/(m·K) | R-16 (RSI-2.8)       |
| Rain control    | Self-adhered membrane (Class II) | -                  | -                | -                                              | -                    |
| Air control     | Self-adhered membrane            | -                  | -                | -                                              | -                    |
| Vapor control   | Integrated with air barrier      | -                  | -                | -                                              | -                    |
| Structure       | Concrete masonry units           | 8"                 | 200 mm           | k = 0.58 Btu/(hr·ft·°F)\<br>λ = 1.00 W/(m·K)   | R-1.2 (RSI-0.21)     |
| Interior        | Plaster finish                   | 5/8"               | 16 mm            | k = 0.41 Btu/(hr·ft·°F)\<br>λ = 0.71 W/(m·K)   | R-0.5 (RSI-0.09)     |

**Total Wall: 15-5/8" (397 mm) | R-19.7 hr·ft²·°F/Btu (RSI-3.5 m²·K/W)**

***

### Wall Type 12: The "Commercial Wall"

**Optimized metal stud system with all insulation exterior**

| Layer           | Material                          | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance   |
| --------------- | --------------------------------- | ------------------ | ---------------- | ---------------------------------------------- | -------------------- |
| Exterior        | Metal panel system                | 1"                 | 25 mm            | k = 314 Btu/(hr·ft·°F)\<br>λ = 543.5 W/(m·K)   | Negligible           |
| **Air cavity**  | **Ventilated air space**          | **3/4"**           | **19 mm**        | **-**                                          | **R-0.9 (RSI-0.16)** |
| Thermal control | Rigid polyiso foam (all exterior) | 3"                 | 75 mm            | k = 0.014 Btu/(hr·ft·°F)\<br>λ = 0.024 W/(m·K) | R-18 (RSI-3.2)       |
| Rain control    | Self-adhered membrane (Class II)  | -                  | -                | -                                              | -                    |
| Air control     | Self-adhered membrane             | -                  | -                | -                                              | -                    |
| Vapor control   | Integrated with air barrier       | -                  | -                | -                                              | -                    |
| Structure       | Metal stud frame (24" OC)         | 6"                 | 152 mm           | k = 314 Btu/(hr·ft·°F)\<br>λ = 543.5 W/(m·K)   | Negligible           |
| Cavity          | Empty (no insulation)             | -                  | -                | -                                              | -                    |
| Interior        | Gypsum drywall                    | 5/8"               | 16 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.56 (RSI-0.10)    |

**Total Wall: 11-3/8" (289 mm) | R-19.5 hr·ft²·°F/Btu (RSI-3.4 m²·K/W)**

***

### Wall Type 13: The "Residential Wall"

**High-performance wood frame with split insulation strategy**

| Layer                      | Material                         | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance   |
| -------------------------- | -------------------------------- | ------------------ | ---------------- | ---------------------------------------------- | -------------------- |
| Exterior                   | Wood siding                      | 3/4"               | 19 mm            | k = 0.080 Btu/(hr·ft·°F)\<br>λ = 0.138 W/(m·K) | Negligible           |
| **Air cavity**             | **Ventilated air space**         | **3/4"**           | **19 mm**        | **-**                                          | **R-0.9 (RSI-0.16)** |
| Thermal control (exterior) | Rigid mineral wool               | 2"                 | 50 mm            | k = 0.025 Btu/(hr·ft·°F)\<br>λ = 0.043 W/(m·K) | R-8 (RSI-1.4)        |
| Rain control               | Self-adhered membrane (Class II) | -                  | -                | -                                              | -                    |
| Air control                | Self-adhered membrane            | -                  | -                | -                                              | -                    |
| Vapor control              | Integrated with air barrier      | -                  | -                | -                                              | -                    |
| Structure                  | Wood stud frame (24" OC)         | 5-1/2" (2x6)       | 140 mm           | k = 0.080 Btu/(hr·ft·°F)\<br>λ = 0.138 W/(m·K) | R-6.9 (RSI-1.21)     |
| Cavity insulation          | Dense-pack cellulose             | 5-1/2"             | 140 mm           | k = 0.027 Btu/(hr·ft·°F)\<br>λ = 0.047 W/(m·K) | R-20 (RSI-3.5)       |
| Interior                   | Gypsum drywall                   | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)    |

**Total Wall: 10-1/16" (255 mm) | R-36.2 hr·ft²·°F/Btu (RSI-6.4 m²·K/W)**

***

### Wall Type 14: Foam-Based Perfect Wall Variation

**Simplified high-performance system using one material for all control layers**

| Layer              | Material                            | Imperial Thickness | Metric Thickness | Thermal Conductivity                           | Thermal Resistance |
| ------------------ | ----------------------------------- | ------------------ | ---------------- | ---------------------------------------------- | ------------------ |
| Exterior           | Stucco finish                       | 7/8"               | 22 mm            | k = 0.41 Btu/(hr·ft·°F)\<br>λ = 0.71 W/(m·K)   | Negligible         |
| All control layers | Closed-cell spray polyurethane foam | 4"                 | 100 mm           | k = 0.016 Btu/(hr·ft·°F)\<br>λ = 0.028 W/(m·K) | R-24 (RSI-4.2)     |
|                    | • Rain control function             | -                  | -                | -                                              | -                  |
|                    | • Air control function              | -                  | -                | -                                              | -                  |
|                    | • Vapor control (Class II)          | -                  | -                | -                                              | -                  |
|                    | • Thermal control                   | -                  | -                | -                                              | -                  |
| Structure          | Concrete masonry units              | 8"                 | 200 mm           | k = 0.58 Btu/(hr·ft·°F)\<br>λ = 1.00 W/(m·K)   | R-1.2 (RSI-0.21)   |
| Interior           | Gypsum drywall                      | 1/2"               | 13 mm            | k = 0.096 Btu/(hr·ft·°F)\<br>λ = 0.166 W/(m·K) | R-0.45 (RSI-0.08)  |

**Total Wall: 13-3/8" (340 mm) | R-25.7 hr·ft²·°F/Btu (RSI-4.5 m²·K/W)**

***

### Vapor Permeance Classifications

| Vapor Class        | Permeance           | Examples                                                                | Typical Applications                                        |
| ------------------ | ------------------- | ----------------------------------------------------------------------- | ----------------------------------------------------------- |
| **Class I**        | ≤ 0.1 perm          | 6 mil polyethylene, foil-faced insulation, closed-cell spray foam (≥2") | Interior vapor barriers in cold climates                    |
| **Class II**       | > 0.1 to ≤ 1.0 perm | Self-adhered membranes, kraft facing, closed-cell spray foam (<2")      | Exterior air/water barriers, moderate climates              |
| **Class III**      | > 1.0 to ≤ 10 perm  | Standard building wraps (Tyvek, Typar), most paint, unfaced fiberglass  | Exterior weather barriers, mild climates                    |
| **Variable Class** | Changes with RH     | Smart vapor retarders (Intello, MemBrain)                               | High-performance assemblies requiring bi-directional drying |

***

### Final Material Thermal Conductivity Reference Table

| Material               | Imperial k-value\<br>Btu/(hr·ft·°F) | Metric λ-value\<br>W/(m·K) | Notes                 |
| ---------------------- | ----------------------------------- | -------------------------- | --------------------- |
| Steel                  | 314                                 | 543.5                      | Severe thermal bridge |
| Aluminum               | 136                                 | 235.4                      | High conductivity     |
| Stone (natural)        | 1.00-2.00                           | 1.73-3.46                  | Variable by type      |
| Concrete (dense)       | 0.90                                | 1.56                       | High thermal mass     |
| CMU (grouted)          | 0.58                                | 1.00                       | Commercial standard   |
| Brick (clay)           | 0.40-0.50                           | 0.69-0.87                  | Traditional masonry   |
| Stucco/Plaster         | 0.40-0.42                           | 0.69-0.73                  | Finish materials      |
| Fiber cement           | 0.29                                | 0.50                       | Siding material       |
| Acrylic finish         | 0.116                               | 0.201                      | EIFS coating          |
| Gypsum board           | 0.096                               | 0.166                      | Interior finish       |
| Vinyl                  | 0.087                               | 0.151                      | Cladding material     |
| Wood (softwood)        | 0.080                               | 0.138                      | Framing lumber        |
| OSB/Plywood            | 0.077                               | 0.133                      | Structural sheathing  |
| Mineral wool (batt)    | 0.029                               | 0.050                      | R-3.5 per inch        |
| Fiberglass batt        | 0.027                               | 0.047                      | R-3.7 per inch        |
| Cellulose (dense-pack) | 0.027                               | 0.047                      | R-3.7 per inch        |
| Mineral wool (rigid)   | 0.025                               | 0.043                      | R-4 per inch          |
| EPS foam               | 0.024                               | 0.041                      | R-4 per inch          |
| XPS foam               | 0.020                               | 0.035                      | R-5 per inch          |
| Closed-cell spray foam | 0.016                               | 0.028                      | R-6 per inch          |
| Polyiso foam           | 0.014                               | 0.024                      | R-6.5 per inch        |

**Thermal Conductivity Unit Definitions:**

* **k-value (Imperial):** Btu/(hr·ft·°F)
* **λ-value (Metric):** W/(m·K)
* **Conversion:** λ = k × 1.731

All thermal conductivity values verified against ASHRAE Handbook of Fundamentals and building science references. Lower values indicate better insulating performance. Materials with k-values above 1.0 are considered thermally conductive rather than insulating.
