| J Series Drawings - 2M/3M Oxford Method External Columns & Casings | |
| J | 4 | 1050 | 3 | External corner column casing |
| J | 4 | 1070 | 3 | Intermediate external column casing |
| J | 4 | 1080 | 3 | Intermediate external expansion (2) column casing |
| J Series Drawings - 2M/3M Oxford Method External Columns & Casings | |
| J | 4 | 1050 | 3 | External corner column casing |
| J | 4 | 1070 | 3 | Intermediate external column casing |
| J | 4 | 1080 | 3 | Intermediate external expansion (2) column casing |