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NFPA 13D - Townhouse Style Construction but NOT a Townhouse by Definition

jar546

jar546

CBO
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First read this:

[F]​

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.

Then read this:
[A] 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 the foundation to roof and with a yard or public way on not less than two sides.


Therefore, if 3 townhouse style units are going to be built, (declared R2 on the drawings) all on the same lot and they don't have their own individual lots, they are not considered townhouses by definition and do not qualify for a 13D system. Do you agree? All three will be on the same parcel.
 
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Why has Florida amended the IBC definition of "townhouse"? Is this apparent impact on IBC 903.3.1.3 an intended or unintended consequence of the amendment of "townhouse"?

I'm not familiar with the requirements for fire separation--are there any construction details that would allow the 3 townhouse style units to be considered 3 separate buildings, each a one family dwelling?

Cheers, Wayne
 
wwhitney said:
I'm not familiar with the requirements for fire separation--are there any construction details that would allow the 3 townhouse style units to be considered 3 separate buildings, each a one family dwelling?
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Hmm, 2015 IBC 706.1 starts off "Each portion of a building separated by one or more fire walls that comply with the provisions of this section shall be considered a separate building." So if there were at least one fire wall between units that complies with IBC 706, then the 3 townhouse style units would be 2 or 3 (if two firewalls) buildings. Each building would then be a dwelling, per the definition of dwelling, so 903.3.1.3 would apply to the resulting one or two family dwellings.

However, that sentence was deleted from 2018 IBC 706.1. So is there no longer a way to take a single structure and cause it to be considered more than one building?

Cheers, Wayne
 
wwhitney said:
Hmm, 2015 IBC 706.1 starts off "Each portion of a building separated by one or more fire walls that comply with the provisions of this section shall be considered a separate building." So if there were at least one fire wall between units that complies with IBC 706, then the 3 townhouse style units would be 2 or 3 (if two firewalls) buildings. Each building would then be a dwelling, per the definition of dwelling, so 903.3.1.3 would apply to the resulting one or two family dwellings.

However, that sentence was deleted from 2018 IBC 706.1. So is there no longer a way to take a single structure and cause it to be considered more than one building?

Cheers, Wayne
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Yeah....They screwed that up:

1735242711876.png
 
jar546 said:
They will be sold as condos and have an HOA which, yeah, I know is not relevant to the codes. Just giving perspective.
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So they can go 13 and get the rating down to 30 minutes or 13R and go 1 hour which is easier and a much cheaper system around here, maybe not so bad in "our crap doesn't freeze land"....
 
steveray said:
Yeah....They screwed that up:

View attachment 14956
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I went looking for this provision on a few previous reviews and found its new location in 503.1, It came into play regarding allowable area, but don't recall it being about classification. If it did I think I would have mistakenly been applying 503.1 the way it existed previously in 706.1 without noticing the distinction.
 
Sifu said:
I went looking for this provision on a few previous reviews and found its new location in 503.1, It came into play regarding allowable area, but don't recall it being about classification. If it did I think I would have mistakenly been applying 503.1 the way it existed previously in 706.1 without noticing the distinction.
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I think Ron and I discussed it a bit here in the past.....Enough of the drift....
 
This depends on your code version. Townhouses are no longer defined by lot lines as of the 2021 code.
1735322508056.png

They went a bit further in the 2024 IRC referring to "imaginary lines" between townhouse units on the same lot.

1735322637272.png

Long story short--it looks like they can use 13D under 2021 and 2024 IRC.
 
That lot line verbiage was always in the CABO code and is still used in a lot of zoning ordinances across the country. I wish the ICC never messed it up by removing the lot line requirement verbiage.
 
steveray said:
If they have a firewall and are structurally independent, and separate buildings, the case could Shirley be made for R3....
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Jar really nailed it : ( single family Dwellings) with property lines separating such units
So, NO 2 Family ( even with separate entrances and No common spaces.) but complicated rated assembly details for stairs
AND seperate Property lines ( even if Fire Walls
 
jar546 said:
I have no idea. I found it back as far as the 2010 FBC, and it was the same. We have a lot of condos and apartments down here. Maybe that has a bearing on it?
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Still a Florida thing. We have a metric boatload of condominiums around this state, built as townhouses under the IRC, with no property lines.
 
Condos have property lines between units. The yards outside the units are typically owned by the homeowner's association.
 
Paul Sweet said:
Condos have property lines between units. The yards outside the units are typically owned by the homeowner's association.
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That is incorrect. Although condos may have their own parcel control number with the county, they only own the airspace within the condo itself. Condos are all on one lot. You can't have a lot line without a lot,, and a condo does not have its own lot.

Here is an example of one single lot with one large building and parking garage with 92 condo units. The yellow lines are the lot lines.
1735929723350.png
 
1979 UBC
1735929510115.png
CABO was used in lieu of the Legacy Codes and recognized a two unit townhouse versus the three required by the IRC. A Townhouse unit is usually easier to finance and insure than a two unit duplex condo.

CABO Definition
Townhouse: Townhouse is a single family dwelling unit constructed in a row of attached separated by property lines and with open space on at least two sides.
 
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