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Joisted Masonry Construction

Construction Class 2


Joisted Masonry


This Construction Brief will give you an overview of Verisk Construction Class 2 – joisted masonry construction. When you've completed this course, you will know what a Verisk report means when it says a building is joisted masonry construction. And you will 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.

Types of joisted masonry

There are several types of masonry used in the exterior bearing walls of joisted masonry buildings:

  • Brick
  • Concrete—either reinforced or nonreinforced
  • Hollow concrete masonry units
  • Tile
  • Stone

Exterior bearing walls may also be any noncombustible materials with fire-resistance ratings of not less than one hour.

Glass Block

Glass block








Concrete - either reinforced or nonreinforced


Hollow concrete blocks


Hollow tile

Variation of joisted masonry construction

Variation Of Joisted Masonry

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 construction

Heavy Timber1

Heavy timber construction

Verisk classifies the building as heavy timber construction if it meets these requirements:

  • Walls of masonry construction
  • Floors of three-inch wood plank or four-inch laminated plank, both surfaced with one-inch flooring
  • Roof of two-inch wood plank, three-inch laminated plank, or 1-1/8 inch tongue-and-groove plywood deck
  • Wood column supports not less than eight-inch x eight-inch, wood beams or girders not less than six-inch x six-inch, or protected metal

Heavy timber advantages

Heavy Timber Advantages

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

Joisted masonry disadvantages


Joisted masonry disadvantages

Joisted masonry construction has these disadvantages:

  • Floors and roofs of combustible materials subject to damage by fire
  • Presence of concealed spaces

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