Joisted Masonry (5022)

Joisted Masonry is a part of NCCI Class Code 5022. Joisted Masonry is also one of six building construction categories established by Insurance Services Office, Inc. (ISO). These six categories are part of the Commercial Lines Manual (CLM) and is designed for the purpose of developing rates for insuring commercial property based upon the likelihood of damage by fire. The CLM description of Joisted Masonry (5022) Construction is considered a building with exterior walls of masonry or fire-resistive construction equipment rated for not less than one hour and with combustible floors and roofs.


Image result for Joisted Masonry

This classification includes worked done on exterior walls with combustible floor and roof. The types of materials used in these walls include adobe, brick, concrete, gypsum block, hollow concrete block, stone, tile, or other similar materials. The code associated with Joisted Masonry (5022) Construction ranks a facility 1-6 based upon how fire resistant the facility is that the business is located or is working on.

Joisted Masonry, Exterior walls, floors, and roof of masonry or fire-resistive materials.

ISO Class 1 is Called Frame. 

Exterior walls of wood, brick veneer, stone veneer, wood ironclad, or stucco on wood. (Construction Code 1)

ISO Class 2 is Called Joisted Masonry (5022).

Exterior walls of masonry material (adobe, brick, concrete, gypsum block, hollow concrete block, stone, tile, or similar materials) with combustible floor and roof.

ISO Class 3 is Called Non Combustible

Exterior walls, floor, and supports made of metal, asbestos, gypsum, or other noncombustible materials.

ISO Class 4 is Called Masonry Non Combustible. 

Same as joisted masonry except that the floors and roof are of metal or other noncombustible materials.

ISO Class 5 is Called Modified or Semi Fire Resistive.

Exterior walls, floors, and roof of masonry or fire-resistive material with a fire resistance rating of at least 1 hour but less than 2 hours.

ISO Class 6 is Called Fire Resistive. 

Exterior walls, floors, and roof of masonry or fire-resistive materials with a fire resistance rating of at least 2 hours.*

What Type of Building Do I have for Insurance Purposes?

What Type of Building Do I have for Insurance Purposes?

This is a question that will be asked of you by insurance agents and loss control professionals with insurance carriers. It is important that you understand why they are asking and how to determine what type of building you have for insurance purposes.

Let us first look at how to determine what ISO construction class you are in. All buildings must be classified into one of 6 construction classes which is broken down for you below. Classification is based on 2 factors.

Strip Mall, Building, Stores, Shops, Retail, Mall

The first is Building Elements. This is the materials used in construction of your structure. Examples are wood, steel, or masonry. The areas that are looked at be built with these materials are the structural frame, interior and exterior load bearing walls, interior and exterior non load bearing walls, floor construction, and roof construction.

The second factor is Fire-Resistance Rating. All the building material used in construction has a rating which means the time it stands up to a fire and how quick it spreads to other areas. Your building is going to be rated by the weakest aspect. For example: if you have a wood roof vs a metal roof you would be rated in a higher premium bracket due to the fire rating of the wood material used to build the roof. Wood burns quicker and does not contain fire like metal.

In summary to determine the ISO class we must know what type of roof, floor, walls, structural frame, and fire rating of building materials. Now let’s determine which class you may fall into.

ISO Class 1 is Called Frame. This is one of the most common classes used in construction. You will have wood walls, brick veneer (single layer for appearance only), stucco, and a wood roof that is not typically anchored. Primary examples of this class would by a residential home or offices that may have been converted from homes to commercial locations.

ISO Class 2 is Called Joisted Masonry. This class consist of concrete or cinder block load bearing walls. Could have structural brick along with a wood roof. The roof in this class is also typically not anchored. Examples of this are residential homes but also single story office building locations that do not have flat roofs. Main difference between this and Class 1 Frame is the increased amount of concrete, cinder, brick for load bearing and structural purposes whereas frame uses wood for these areas.

ISO Class 3 is Called Non Combustible. Construction of this type of structure will contain a minimal amount of wood. Load bearing walls will be brick, stone, concrete tilt up, or metal. Frame is generally steel. The roof is a steel deck which is flat or has a slight slope. Roofs could also be metal. The roof is anchored to the structure with metal bolts. Examples of this class would be warehouses, storage facilities, and manufacturing plants.

ISO Class 4 is Called Masonry Non Combustible. This structure is a class above ISO Class 3 because it reinforces its load bearing walls. They are usually tilt up concrete, precast concrete masonry, or concrete blocks on steel. The roof systems are steel decks, poured structural concrete on steel decks, or metal. The roof is also anchored by metal bolts. Examples of this class would be schools, shopping centers, outdoor malls, and warehouses, etc.

ISO Class 5 is Called Modified or Semi Fire Resistive. This class has semi wind resistive walls made out of protected steel or precast concrete tilt up. The roofs are similar to class 3 and 4 in which they are a steel deck or poured structural concrete. The roof is anchored by metal bolts. The heavy construction nature of this structure makes leads us to examples such as high rise office buildings.

ISO Class 6 is Called Fire Resistive. This is the strongest class possible. Walls are concrete, very well protected steel. Floors are 4” cast in place concrete, precast concrete or protected steel. The structure is wind resistive. Roofs are poured structural concrete and anchored by metal bolts. Office buildings are another example of this class along with parking garages.

The key thing to remember in determining your building class is you are only as strong as your weakest element. This is a quick overview of the classes and if you are looking for more details or have questions than reach out to your agent or insurance carrier and they will be able to help you out.


The content included within My Insurance Question is a creation of the experts at The Insurance Shop LLC. Formed in 2005, this agency has developed relationships with more then two dozen carriers who are hungry to offer coverage to multiple industries. Those relationships allow their agents to get the best value on all types of commercial insurance. If you are ready for a new look at your coverage, give us a call at 800-800-4864.