Are Townhouse Complexes Group R-2 or R-3?

1/2/2025

Are townhouse complexes (3 or more side by side and separated by fire barrier) considered R-2 or R-3?

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12 Comments

Pete H

1/2/2025 06:25:53 am

Unless the units are for a congregate living facility, boarding house, or lodging house that meet the occupancy limitations outlined in IBC 310.5 for R-3: I'd steer towards R-2.

Live Units, a building that contains at least three dwelling units. This sounds like R-2.

Hector Marin

1/2/2025 08:49:44 am

Good morining,

R3 would require that there be property lines between each unit.

R2 would not have property lines between the units.

Hector Marin

1/2/2025 08:53:11 am

According to the IBC

310.4 Residential Group R-2
Assembly
Diagram
Residential Group R-2 occupancies containing sleeping units or more than two dwelling units where the occupants are primarily permanent in nature, including:
Apartment houses
Boarding houses (nontransient) with more than 16 occupants
Congregate living facilities (nontransient) with more than 16 occupants
Convents
Dormitories
Fraternities and sororities
Hotels (nontransient)
Live/work units
Monasteries
Motels (nontransient)
Vacation timeshare properties

310.5 Residential Group R-3
Diagram
Residential Group R-3 occupancies where the occupants are primarily permanent in nature and not classified as Group R-1, R-2, R-4 or I, including:

Buildings that do not contain more than two dwelling units
Boarding houses (nontransient) with 16 or fewer occupants
Boarding houses (transient) with 10 or fewer occupants
Care facilities that provide accommodations for five or fewer persons receiving care
Congregate living facilities (nontransient) with 16 or fewer occupants
Congregate living facilities (transient) with 10 or fewer occupants
Lodging houses with five or fewer guest rooms

Brian M

1/2/2025 09:16:30 am

Could you please cite a reference that shows the lot lines in relation to R2/R3? I'm interested in where this comes from. Thank you.

Jose Figueroa

1/2/2025 09:45:39 am

It depends! In the International Building Code (IBC) and many other building codes, townhouse complexes are typically classified as R-3 occupancy.

The R-3 occupancy classification generally includes separate single-family dwellings, such as single-family homes, duplexes, and townhouses. These dwellings are usually separated by a wall and have their own independent means of egress. In contrast, R-2 occupancy is designated for buildings that contain more than two units, such as apartments, condominiums, dormitories, and certain types of residential rental communities.

Conrad

1/2/2025 12:19:19 pm

Can you elaborate more on townhouses having an R-3 occupancy under the IBC?

Under IBC 2018, Section 310.4 R-3, the first example is "Buildings that do not contain more than two dwelling units".
Under the same IBC 2018, the definition of Townhouse is "TOWNHOUSE. A single-family dwelling unit constructed in a group of three or more attached units ..."

Chris Miller

1/2/2025 12:53:20 pm

Townhouses are covered under IRC (international Residential Code) as single/two family dwelling.

Jack G

1/2/2025 01:49:45 pm

I believe you should look at the IRC as this might be an application for an R3 dwelling unit in an R2 building.
The IBC, also is for 3 or more units - R3 .

Charles Riforgiate

1/3/2025 08:33:03 am

First step before any design considerations you need to establish building or sprinkler requirements based on the applicable code; IRC or IBC.
The IRC does not categorize by occupancy classifications. If the townhouse is designed and constructed within the definition and limitations of the IRC it is a "Townhouse" If it falls outside of the scope of the IRC (refer to scope & definition) then it must be designed and built in accordance with the IBC-typical occupancy classification of R-3
IRC townhouse -NFPA 13D or 13R
IBC R-3 -NFPA 13 or 13R
See Meyer Fire "When can I use NFPA 13D"

Hector Marin

1/3/2025 08:43:54 am

The International Residential Code states:

This comprehensive, stand-alone residential code establishes minimum regulations for one- and
two-family dwellings and townhouses using prescriptive provisions.

... for regulating and governing the construction, alteration, movement, enlargement, replacement, repair, equipment, location, removal and demolition of detached one- and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories in height with separate means of egress.

101.2 Scope.
The provisions of the International Residential Code for One- and Two-family Dwellings shall apply to the construction, alteration, movement, enlargement, replacement, repair, equipment, use and occupancy, location, removal and demolition of detached one- and two-family dwellings and townhouses not more than three stories above
grade plane in height with a separate means of egress.

RESIDENTIAL BUILDING.
For this chapter, includes
detached one- and two-family dwellings and multiple single-family dwellings (townhouses) as well as Group R-2, R-3 and
R-4 buildings three stories or less in height above grade plane.

APPENDIX U
SOLAR-READY PROVISIONS
DETACHED ONE- AND TWO-FAMILY DWELLINGS, MULTIPLE SINGLE-FAMILY DWELLINGS (TOWNHOUSES)

Todd E Wyatt

1/3/2025 03:51:01 pm

The scoping Code (e.g. IBC-2024) differentiates between Group R-2 ( … containing sleeping units or MORE THAN TWO DWELLING UNITS where the occupants are primarily PERMANENT in nature …) and Group R-3 ( … the occupants are primarily PERMANENT in nature and NOT CLASSIFIED as Group R-1, R-2, R-4 or I).

You state that “the townhouse complexes … 3 or more side by side“ are “separated by fire barrier(s).”

To be considered “separate buildings” the townhouses would need to be separated by FIRE WALLS (FW). FWs only create “separate buildings” for “purposes of determining area limitations, height limitations and type of construction” and not for Occupancy Classification (OC) purposes.

Since Group R-3 states “Buildings that do not contain MORE THAN TWO DWELLING UNITS”, this Project should be classified as Group R-2.

Per the scoping Code (IBC-2024), “an AUTOMATIC SPRINKLER SYSTEM installed in accordance with Section 903.3 shall be provided THROUGHOUT ALL BUILDINGS WITH A GROUP R FIRE AREA.”

Townhouses are permitted to use NFPA 13D Sprinkler Systems.

Todd E Wyatt

1/3/2025 03:51:27 pm

REFERENCES
IBC-2024
Chapter 2 Definitions
DWELLING. A building that contains one or two dwelling units used, intended or designed to be used, rented, leased, let or hired out to be occupied for living purposes.
DWELLING UNIT. A single unit providing complete, independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking and sanitation.
TOWNHOUSE. A building that contains THREE OR MORE attached townhouse units.
TOWNHOUSE UNIT. A single-family dwelling unit in a townhouse that extends from the foundation to the roof and has a yard or public way on not fewer than two sides.

Chapter 3 Occupancy Classification and Use
310.3 Residential Group R-2
Residential Group R-2 occupancies containing sleeping units or more than two dwelling units where the occupants are primarily permanent in nature, including:
1. Apartment houses
2. Congregate living facilities (nontransient) with more than 16 occupants
3. Boarding houses (nontransient)
4. Convents
5. Dormitories
6. Emergency services living quarters
7. Fraternities and sororities
8. Monasteries
9. Hotels (nontransient) with more than five guest rooms
10. Live/work units
11. Motels (nontransient) with more than five guest rooms
12. Vacation timeshare properties

310.4 Residential Group R-3
Residential Group R-3 occupancies where the occupants are primarily permanent in nature and not classified as Group R-1, R-2, R-4 or I, including:
1. Buildings that do not contain more than two dwelling units
2. Care facilities that provide accommodations for five or fewer persons receiving care
3. Congregate living facilities (nontransient) with 16 or fewer occupants
4. Boarding houses (nontransient)
5. Convents
6. Dormitories
7. Emergency services living quarters
8. Fraternities and sororities
9. Monasteries
10. Congregate living facilities (transient) with 10 or fewer occupants
11. Boarding houses (transient)
12. Lodging houses with five or fewer guest rooms
13. Hotels (nontransient) with five or fewer guest rooms
14. Motels (nontransient) with five or fewer guest rooms

Chapter 5 General Building Heights and Areas
Section 503 General Building Height and Area Limitations
503.1 General
Unless otherwise specifically modified in Chapter 4 and this chapter, building height, number of stories and building area shall not exceed the limits specified in Sections 504 and 506 based on the type of construction as determined by Section 602 and the occupancies as determined by Section 302 except as modified hereafter. Building height, number of stories and building area provisions shall be applied independently. FOR THE PURPOSES OF DETERMINING AREA LIMITATIONS, HEIGHT LIMITATIONS AND TYPE OF CONSTRUCTION, EACH PORTION OF A BUILDING SEPARATED BY ONE OR MORE FIRE WALLS COMPLYING WITH SECTION 706 SHALL BE CONSIDERED TO BE A SEPARATE BUILDING.

Chapter 9 Fire Protection and Life Safety Systems
903.2 Where Required
903.2.8 Group R
An AUTOMATIC SPRINKLER SYSTEM installed in accordance with Section 903.3 shall be provided THROUGHOUT ALL BUILDINGS WITH A GROUP R FIRE AREA.
903.3 Installation Requirements
Automatic sprinkler systems shall be designed and installed in accordance with Sections 903.3.1 through 903.3.8.
903.3.1 Standards
Automatic sprinkler systems shall be designed and installed in accordance with Section 903.3.1.1 unless otherwise permitted by Sections 903.3.1.2 and 903.3.1.3 and other chapters of this code, as applicable.
903.3.1.1 NFPA 13 Sprinkler Systems
903.3.1.2 NFPA 13R Sprinkler Systems
903.3.1.3 NFPA 13D Sprinkler Systems
Automatic sprinkler systems installed in one- and two-family dwellings; Group R-3; Group R-4, Condition 1; and TOWNHOUSES shall be permitted to be installed throughout in accordance with NFPA 13D.

Are Townhouse Complexes Group R-2 or R-3?

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