What are the 5 building Construction types

The 5 types of building construction are: Type I (Fire-Resistive), Type II (Non-Combustible), Type III (Ordinary), Type IV (Heavy Timber), and Type V (Wood-Framed), as classified by the International Building Code (IBC) based on fire resistance and structural materials.

Most people would look at a building and view it as just that: a building. But as a contractor, you see buildings differently.

Building elements like the structure, walls, floors, and roof are all telling of a building’s class. If you don’t already have a keen eye for those details, it’s important to know the five types of building construction, especially if you’re in the fire restoration business.

Buildings can be categorized into five different types of construction: fire-resistive, noncombustible, ordinary, heavy timber, and wood-framed.

Summary Comparison Table

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Fire-resistive Type I (IA and IB)

With this type of construction, walls, partitions, columns, floors, and roofs are the most non-combustible when it comes to fire-resistant ratings.

These structures are usually easy to spot based on their height. Fire-resistive buildings are more than 75 feet tall and made of poured concrete and protective steel. They're designed to withstand the effects of fire for a long time to prevent a fire from spreading.

Ventilation in these types of buildings is not an option because the roof must also be composed of non-combustible materials.

Key Characteristics:

• Structural frame made of poured concrete and protected steel
• Fire-resistance rating of 2-3 hours for structural elements
• Buildings typically exceed 75 feet in height
• Non-combustible roof prevents vertical ventilation
• Common uses: high-rises, hospitals, large commercial buildings

Non-combustible Type II (IIA and IIB)

Non-combustible buildings are similar to the fire-resistive type where walls, partitions, columns, floors, and roofs are non-combustible. However, they provide less fire resistance and do not withstand the effects or spreading of fire as well as Type I.

This type gets its name “non-combustible” not because of its resistance to fire but because of the fuel that the building contributes. Newer school buildings are common examples of this type of construction.

These buildings typically have a metal floor and metal roof with masonry or tilt-slab walls. They're the least stable in terms of collapse when exposed to fire.

Key Characteristics:

• Metal framing with masonry or tilt-slab walls
• Fire-resistance rating of 1-2 hours (IIA) or unrated (IIB)
• Non-combustible materials but lower fire resistance than Type I
• Least stable construction type during fire exposure
• Common uses: schools, warehouses, newer commercial buildings

Ordinary Type III

These buildings are also called brick-and-joist structures. This type of construction has brick or block walls with a wooden roof or floor assembly that is not protected against fire.

All or part of the interior structural elements (frame, floors, ceilings, etc.) is combustible/wood. Vertical ventilation in these types of buildings is possible.

You will see ordinary construction in both old and new buildings.

Key Characteristics:

• Exterior walls of brick or concrete block (minimum 2-hour rating)
• Interior framing, floors, and roof of wood construction
• Allows vertical ventilation during firefighting operations
• Found in both historic and modern buildings
• Common uses: older commercial buildings, retail stores, mixed-use structures

Heavy Timber Type IV

Type IV buildings have non-combustible exterior walls and interior elements. These buildings are made out of solid or laminated wood.

All wooden members must meet dimensional requirements. Wood columns, beams, and girders must be at least 8 inches thick. Heavy planks for floors and roofs must be at least 6 inches thick.

If these types of buildings catch fire, they require large volumes of water to extinguish, but they hold up well against fire and don’t collapse easily due to their structural mass.

Key Characteristics:

• Columns, beams, and girders minimum 8 inches thick
• Floor and roof planks minimum 6 inches thick
• Non-combustible exterior walls required
• Resists collapse due to heavy structural mass
• Common uses: historic buildings, churches, renovated warehouses

Wood-Framed Type V

Wood-framed buildings are the most combustible out of all the types. They are the only construction type that allows combustible exterior walls. Type V also allows a combustible interior (structural frames, walls, floors, and roofs) made entirely or partly out of wood. This type is commonly found in modern homes. They often have exposed wood, so there is no fire resistance. It ignites significantly but is reasonably resistant to collapse unless it is a lightweight construction, in which case it will fail within minutes.

Key Characteristics:

• Wood framing permitted for all structural elements including exterior walls
• Type VA provides 1-hour fire resistance; Type VB is unrated
• Most combustible of all construction types
• Lightweight construction may fail rapidly in fire conditions
• Common uses: single-family homes, apartments, small commercial buildings

Quick Comparison: Fire Resistance Ranking

From Most to Least Fire-Resistant:

1. Type I (Fire-Resistive) – Highest protection with 2-3 hour ratings; designed for high-rises and critical facilities where fire containment is essential.
2. Type II (Non-Combustible) – Good protection with non-combustible materials but lower ratings (1-2 hours); suitable for schools and commercial buildings.
3. Type IV (Heavy Timber) – Moderate protection; large wood dimensions char slowly rather than burn quickly, providing 1-2 hours of resistance.
4. Type III (Ordinary) – Limited protection; non-combustible exterior walls protect against external fire spread, but combustible interiors present risk.
5. Type V (Wood-Framed) – Lowest protection with 0-1 hour ratings; combustible throughout, making it the most vulnerable to fire damage.

Get to Know the 5 Construction Types

With all the different kinds of buildings around us, you may want to observe the materials and structures around you as you travel day-to-day.

Take notes in your construction CRM to compare the qualities of different buildings yourself. Doing so will give you more experience in developing an eye for building construction.

By distinguishing these building constructions into five types, you can personally decide which structure is best for new construction. Again, those building construction types include fire-resistive, non-combustible, ordinary, heavy timber, and wood-framed.

What types of construction do you primarily work on? Let us know in the comments below!