This Construction Brief will give you an overview of ISO's Construction Class 2 – joisted masonry construction. When you've completed this course, you'll know what an ISO report means when it says a building is joisted masonry construction. And you'll understand why a particular structure is—or isn't—joisted masonry.
Buildings with exterior walls of masonry or fire-resistive construction rated for not less than one hour and with combustible floors and roofs.
Variation of joisted masonry construction
There's one variation on joisted masonry construction that doesn't change the construction class—heavy timber or mill construction.
Heavy timber construction uses wood members much larger than those found in frame (Construction Class 1) or other joisted masonry construction.
If the building uses steel columns or beams for walls, the beams must be protected so they have a fire-resistance rating of not less than one hour.
Heavy timber advantages
Heavy timber construction offers these advantages:
- Harder to ignite
- Consumed more slowly by fire
- More structural stability
- Greater salvage value
- Lack of concealed spaces