• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

Definition of attached?

Sifu

Sifu

SAWHORSE
Joined
Sep 3, 2011
Messages
2,813
Got a call from a guy wanting to build a separate dwelling unit on his lot for himself. He is disabled and is planning for the time he will need on-site care. He was told by zoning that he can't do this as a detached structure. He wants to know what constitutes "attached". I want to help the guy out but am not sure where to draw the line. Does the code give any direction on this? I can find no definitions that help. Usually a breezeway can connect a detached building but is separated by rated construction or at least 1/2" drywall. I have always viewed these as detached buildings. So I am wondering what it would take to make this structure attached. Also, there is a nagging memory of not permitting this due to the number of independant dwelling units, though that may not be from code or at least the IRC. Any ideas?
 
It is a zoning definition. Ours allowed a breezeway up until last year. Had a few where the breezeway was removed and the lots condo to avoid subdivision regulations so now they have to be adjacent but are allowed to be structurally indpendent similar to the old townhouse requirements
 
I'll look at the zoning ordinance to see if they define it. If they do they don't know it because it was them that sent the guy to me to see what I would require. In the absence of a better definition I am leaning towards a covered breezeway with some fire protection between the units just in case. My only concern is what it can become and where it stops but if the code permits it and the zoning ordinance permits it who am I to say nay?
 
attached would be to the primary structure located on the lot. a detached building according to the IBC is a single story building used for storage. he should be able to build an addition onto his home to provide the special needs he may anticipate in the future. a separate structure would be dependent on the local zoning regulations. normally zoning would only allow one detached structure on a lot. of course if you have a zoning board of appeals that could be a route to allow a second structure.
 
High Desert said:
Have zoning define attached since they have the requirement.
Click to expand...
Agree with High Desert, for clarity.

In our jurisdiction though, we have a common roof line as a requirement. We also have provisions for ADU's "accessory dwelling units" that are by a lottery system each year, based on number of SFR's the previous year. They are limited to 1000 square feet. If you want to attach them with a breezeway, the breezeway must be conditioned space and that space counts towards the 1000 square feet.

Sounds a bit goofy, but otherwise, we would have people putting up a 400 foot piece of ribbion between buildings and saying "they are attached".
 
Agree with the others, have the local ZO tell you what constitutes attached, then go from there.
 
Agree with others, you need to start at the Planning Dept. Here, city allows 'granny flats' if there is room on the lot. Lot coverage is limited to 40%. County will not allow a second dwelling unit unless your property is over 15 acres.
 
Sifu said:
Got a call from a guy wanting to build a separate dwelling unit on his lot for himself. He is disabled and is planning for the time he will need on-site care. He was told by zoning that he can't do this as a detached structure. He wants to know what constitutes "attached". I want to help the guy out but am not sure where to draw the line. Does the code give any direction on this? I can find no definitions that help. Usually a breezeway can connect a detached building but is separated by rated construction or at least 1/2" drywall. I have always viewed these as detached buildings. So I am wondering what it would take to make this structure attached. Also, there is a nagging memory of not permitting this due to the number of independant dwelling units, though that may not be from code or at least the IRC. Any ideas?
Click to expand...
What about water/sewer? Power? Telecom? Does the applicant intend to sub-feed the attached residence from the existing primary residence? If not it is detached.
 
As many have already stated, it is a zoning regulation that needs to be defined by the planning department...however, in our case, and it sounds like your case too, they will often defer to the building department for construction definitions in order to avoid conflict. We have worked out a definition with our planning department to include a roof structure connection. While this works for attaching structures together within our jurisdiction, our zoning prohibits multi-family residences in typical single family residential zones (no more living units above the garage, no more guest houses, etc.).

good luck.
 
I'll start by saying the zoning director is also the "building codes director", yea, if you are familiar with my whining you know the guy hates me and regulation of any kind. He already told the guy it is permitted as long as it is attached because the zoning there permits duplexes. The zoning ordinance does not define attached. He told the guy he could attach it in any way he wanted, so I guess thats the definition. I thought about the the utilities and such this morning on the way in but since in our infinate quest to do as little as possible we don't enforce that stuff it really doesn't matter. My concern is the same as righter's; where would it end? But I think the zoning would stop it at a single "duplex". Don't get me wrong, I want to allow it. I just want to make sure there is nothing that says I shouldn't.

All good thoughts, thanks.
 
tmurray said:
If zoning can't define what is attached then how can they enforce it?
Click to expand...
As if that has ever been a consideration when coming up with a zoning regulation (not saying that it shouldn't). We constantly struggle to enforce zoning regulations that are almost entirely unenforceable (e.g. requirement for a tree in front and rear yard of all NSFRs, required to be installed within two years of the construction of the NSFR).
 
Take it to the Board of Appeals for an interpretation.........
 
A couple of ways it has been interpreted here in the past.

Covered breezeway

Connection of a common wall having a dimension not less than 7' - that was based on the code requirement for minimum dimension of a room
 
Back when I was behind the counter, we had a grandfathered second unit which was attached by means of a carport.

It sat on the rear lot line adjacent to a street (lot had streets on three sides). It never would be approved as a variance.

The owner was doing extensive renovations and zoning told him that so long as he left one carport beam, the unit would remain attached.

As can be expected, the owner's progress was sloooowwww.

Three years in fact.

It was in my neighborhood.

I walked by it every day with the dogs at least once.

No good deed goes unpunished.
 
"It was in my neighborhood.

I walked by it every day with the dogs at least once.

No good deed goes unpunished."

Good one......... :devil
 
Drumming up an old thread here. I have two projects in the works that both involve "attaching" a new dwelling unit to an existing dwelling unit to circumvent the zoning requirements and size constraints for accessory detached dwellings. The end result is an enclosed mechanical/storage space between the two dwellings making them technically "attached" but separated by the size of the mechanical/ storage space of 5 ft. or more. My question to the group is what do i need to look for as far as two family dwelling unit fire separation requirements if any? Thanks for any feedback.
 
2 hour or two 1 hour walls from the foundation to the roof

R302.2.1 Continuity.
The fire-resistance-rated wall or assembly separating townhouses shall be continuous from the foundation to the underside of the roof sheathing, deck or slab. The fire-resistance rating shall extend the full length of the wall or assembly, including wall extensions through and separating attached enclosed accessory structures.

R302.2.2 Parapets.
Parapets constructed in accordance with Section R302.2.3 shall be constructed for townhouses as an extension of exterior walls or common walls 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.

Exception: A parapet is not required in the two cases above when the roof is covered with a minimum class C roof covering, and the roof decking or sheathing is of noncombustible materials or approved 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 a minimum of nominal 2-inch (51 mm) ledgers attached to the sides of the roof framing members, for a minimum distance of 4 feet (1219 mm) on each side of the wall or walls and there are no openings or penetrations in the roof within 4 feet (1219 mm) of the common walls.

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.
 
Got that part of it. This is a single story narrow breezeway like structure between the two dwelling units with a fire separation greater than 5 ft. between the two dwellings. So I need to have a 2hr or two 1hr walls at each end of the breezeway? Or another scenario I have is two dwelling units separated by two 2 car garages side by side. So the garage party wall would need to be 2hr or two 1hrs? I think that the exterior wall fire resistance rating based on separation distance makes more sense
 
Turns out the breezeway trick isn't going to fly for the applicant according to our zoning definition of duplex. Two attached dwelling units in a single structure side by side.
 
You must log in or register to reply here.
Top