Townhouses and Roof Penetrations within 4 feet

[jar546]

Is it still code to have all roof penetrations at least 4' away from the wall that separates townhouses? I remember writing that up back in the day but have not come acros that in a while. Is it still code?

 

[classicT]

Kinda... there is a requirement that relates to parapets.

2021 IRC R302.2.4 Parapets for Townhouses​

Parapets constructed in accordance with Section R302.2.5 shall be constructed for townhouses as an extension of exterior walls or common walls separating townhouse units in accordance with the following:

1. Where roof surfaces adjacent to the wall or walls are at the same elevation, the parapet shall extend not less than 30 inches (762 mm) above the roof surfaces.
2. Where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is not more than 30 inches (762 mm) above the lower roof, the parapet shall extend not less than 30 inches (762 mm) above the lower roof surface.
   
   1. Exception: A parapet is not required in the preceding two cases where the roof covering complies with a minimum Class C rating as tested in accordance with ASTM E108 or UL 790 and the roof decking or sheathing is of noncombustible materials or fire-retardant-treated wood for a distance of 4 feet (1219 mm) on each side of the wall or walls, or one layer of 5/8-inch (15.9 mm) Type X gypsum board is installed directly beneath the roof decking or sheathing, supported by not less than nominal 2-inch (51 mm) ledgers attached to the sides of the roof framing members, for a distance of not less than 4 feet (1219 mm) on each side of the wall or walls and any openings or penetrations in the roof are not within 4 feet (1219 mm) of the common walls. Fire-retardant-treated wood shall meet the requirements of Sections R802.1.5 and R803.2.1.2.
3. A parapet is not required where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is more than 30 inches (762 mm) above the lower roof. The common wall construction from the lower roof to the underside of the higher roof deck shall have not less than a 1-hour fire-resistance rating. The wall shall be rated for exposure from both sides.

 

[chief-inspector]

The townhouse section has always been lacking and must be interpreted by the building code official. This section states to use 5/8 x but does not tell you how to attach it which is covered in the IBC. But whether you can use the IBC in regards to the IRC is still a question. Most smart builders are using a 2 hour shaft wall system now between townhouse units that has no penetrations. Since the townhouse is a single family residence it should not have penetrations from another house running into it. Electric feeds violate this principle all the time.

 

[jar546]

Since the townhouse is a single family residence it should not have penetrations from another house running into it. Electric feeds violate this principle all the time.

In Florida, if it's not on its own lot, it's not a townhouse. This is not the case outside of Florida. No utilities should be running through the property lines of another which is why all electrical services are located on each townhouse. Otherwise, they are R2's.

 

[chief-inspector]

In Florida, if it's not on its own lot, it's not a townhouse. This is not the case outside of Florida. No utilities should be running through the property lines of another which is why all electrical services are located on each townhouse. Otherwise, they are R2's.

They may be R2 but they are inspected by residential inspectors and classified at the property appraiser as single-family dwellings. Many times they put all the meters on the side of one townhouse and feed all the units underground from that panel area.

 

[jar546]

They may be R2 but they are inspected by residential inspectors and classified at the property appraiser as single-family dwellings. Many times they put all the meters on the side of one townhouse and feed all the units underground from that panel area.

Not in this county.
These look like and are built like townhouses but they don't meet the definition of a townhouse because they are not on their own lots.

The county and our office classifies them as condominiums R2, not single family.


I am not sure why your county is not doing it correctly.

 

[Yankee Chronicler]

"Condominium" is a form of ownership, which is not a consideration under the building codes. Under the IRC, townhouses are attached dwelling units that each have an exit directly to the exterior. The actual IRC definition is:

[RB]TOWNHOUSE. A building that contains three or more
attached townhouse units.
[RB] TOWNHOUSE UNIT. A single-family dwelling unit
in a townhouse that extends from foundation to roof and that
has a yard or public way on not less than two sides.

No mention of form of ownership.

 

[jar546]

"Condominium" is a form of ownership, which is not a consideration under the building codes. Under the IRC, townhouses are attached dwelling units that each have an exit directly to the exterior. The actual IRC definition is:



No mention of form of ownership.

Florida Building Code

[RB] TOWNHOUSE. A single-family dwelling unit not exceeding three stories in height constructed in a group of two or more attached units with property lines separating such units in which each unit extends from foundation to roof and with a yard or public way on not less than two sides.

 

[mtlogcabin]

1997 CABO

The same definition was also used in the SBCCI legacy code. Notice a townhouse is 2 units or more not 3 units as defined in the I-Codes.
Our zoning requires a property line between units. IMHO a property line should be required.

 

[chief-inspector]

It says a unit separated by property lines which means it is a single family residence and must meet the zoning code. A condo or apartment does not have separate property lines but lines from the interior walls.

 

[chief-inspector]

Not in this county.
These look like and are built like townhouses but they don't meet the definition of a townhouse because they are not on their own lots.
View attachment 11847
The county and our office classifies them as condominiums R2, not single family.
View attachment 11848

I am not sure why your county is not doing it correctly.

You are correct what I meant is condo and apartments are inspected as commercial and a townhouse with single ownership with property lines going down to the dirt or R3 if they are self-contained and have no other occupancies above them. Zoning codes and county ordinances define ownership and things like that.

 

[chief-inspector]

"Condominium" is a form of ownership, which is not a consideration under the building codes. Under the IRC, townhouses are attached dwelling units that each have an exit directly to the exterior. The actual IRC definition is:



No mention of form of ownership.

The part where it says property lines define the ownership as a single family residence and not a condo or apartment. But the zoning code covers that more.

 

[chief-inspector]

"Condominium" is a form of ownership, which is not a consideration under the building codes. Under the IRC, townhouses are attached dwelling units that each have an exit directly to the exterior. The actual IRC definition is:



No mention of form of ownership.

The form of ownership is mentioned in property lines which are assumed to go down to the dirt and below and that means you can't run utilities under the structure to another unit in R3. But that is more a matter of ordinances and zoning regulations. Here is a discussion about fire codes and sprinkler systems regarding townhouses. https://www.meyerfire.com/daily/rea...imply,this is student housing, but Is student

 

[steveray]

I think we stay away from property lines because of zoning...

 

[Paul Sweet]

The 2021 IRC defines Townhouse as "A building that contains three or more townhouse units", and Townhouse Unit as "A single family dwelling unit in a townhouse that extends from foundation to roof and that has a yard or public way on not less than two sides."

The property line might be a state amendment.