# IRC Accessory Structure Proposed Interpretation 23-12



## righter101 (Jun 25, 2012)

Hey everyone.  I was gone for a few weeks, I will have to scan the boards to see what I missed.  Hope all is well.

THE ICC has a proposed committee interpretation #23-12 (You can't access it directly from the ICC site unless you are a member.) But I will post it here.

They are taking public comment until Thursday.  I just wanted to see what everyone's opinion on this was.

ACCESSORY STRUCTURE. A structure not greater than 3,000 square feet (279 m2) in floor area, and not over two stories in height, the use of which is customarily accessory to and incidental to that of the dwelling(s) and which is located on the same lot.

QUESTION: Is the floor area limitation of 3,000 square feet the combined floor area of all stories above grade plane plus any basement floor area?

ANSWER: (Proposed by committed): No.  The floor area limitaiton is per story.  The floor area is not the combined floor area of all the stories, it is the area pler story.  Each story, including the basemetn, of the accessory structure could be 3,000 square feet.

This is their draft proposal.  We (our jurisdiction) has already weighed in on this.  This interpreation would allow creation of up to 9000 square foot garages/accessory structures.

Curious what others think about this.  If you are an ICC member, there is still time to provide feedback.

Thanks


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## tmurray (Jun 25, 2012)

If your jurisdiction has a problem with the maximum size why don't you just restrict them by local law. Here in Canada our code does not restrict accessory structures at all (unlimited size and storeys), but our local laws restrict height and size.

I do have a problem of the use of the word "customarily" in that definition as you could have a "accessory" building that is not accessory of incidental to the use which would (according to our code) make it a major occupancy.


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## Papio Bldg Dept (Jun 25, 2012)

From an enforcement standpoint, I am not a big fan of residential accessory structures larger than the main structure, as they don't fit in with our proposed residential comprehensive development plan or our existing zoning regulations, but then again we didn't adopt the IZC either.  The largest detached residential garage we have constructed in our ETJ is 7,000 sf, and the largest attached is roughly 3,500 sf.

I can however see circumstances where they may be applicable, as with rural acreage lots, where specialized equipment and recreational indoor vehicle storage may be desired.


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## Big Mac (Jun 25, 2012)

I think they have rocks in their heads.  Should be a max of 3,000 square feet total.  An accessory building should be just that.  It certainly should not be the domaintant structure.


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## righter101 (Jun 25, 2012)

That was my thinking.  we have always interpreted it to mean a total of 3,000 sq.ft., not per floor.

We would welcome permit applications for something larger, as it could be constructed under the provisions of the IBC for a U or S2, depending on the use.

Chapter 4 (IBC) has some specific limits on private garages, this appears to be contrary to all that.


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## fatboy (Jun 25, 2012)

I don't necessarily agree with the interpretation, but it would get kicked here anyway under zoning code.


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## High Desert (Jun 25, 2012)

I wonder how they came up with a definition of floor area?


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## brudgers (Jun 25, 2012)

I think that accessory structures should be left as part of zoning.  Putting size limits in the IRC is silly, IMO.


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## Builder Bob (Jun 26, 2012)

I wish my Home had a grand total of 3,000 SF.....


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## mtlogcabin (Jun 26, 2012)

The IRC is quit clear in that it has always been per floor area which would be per story. Zoning is the place to limit the size of accessory structures on residential property. Out in the country large shops or barns are common and the majority are truly accessory to the property they are located on.


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## Min&Max (Jun 26, 2012)

Does not matter. Local zoning requirement will rule.


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## Paul Sweet (Jun 26, 2012)

I'm guessing this means that an accessory structure less than 3000 SF per story can be constructed under the IRC.  Any larger and it falls under the IBC.  I don't think there is any intent to trump zoning restrictions.


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## Big Mac (Jun 26, 2012)

The definition of an accessory structure in the 2009IRC.  A structure not greater than 3000 square feet in floor area, and not over two-stories in height, the use of which is customarily accessory to and incidental to that of the dwellings and which is located on the same lot.

3,000 square feet of floor area / not over two-stories in height.

That could be 3,000 square feet on one floor.  1,500 square feet on two floors.  2,000 square feet down and 1,000 square feet up.

It does not say 3,000 square feet on each of two floors.  It does not say a 3,000 square footprint.  it says 3,000 square feet of floor area, period.


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## fatboy (Jun 26, 2012)

That was my take on it also Big Mac.........but, I've been wrong before.

Like I said, haven't had to waste time on it, Planning would kill anything that size. Max 60% of primary structure, and can not be taller than primary structure. We don't have McMansions here.


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## mtlogcabin (Jun 26, 2012)

Big Mac said:
			
		

> The definition of an accessory structure in the 2009IRC. A structure not greater than 3000 square feet in floor area, and not over two-stories in height, the use of which is customarily accessory to and incidental to that of the dwellings and which is located on the same lot.3,000 square feet of floor area / not over two-stories in height.
> 
> That could be 3,000 square feet on one floor. 1,500 square feet on two floors. 2,000 square feet down and 1,000 square feet up.
> 
> It does not say 3,000 square feet on each of two floors. It does not say a 3,000 square footprint. it says 3,000 square feet of floor area, period.


I see your point. It would be nice if they had said "aggregate floor area" if that is what the intent is.

Basements have never been include in the area of a building.

Agree with Paul Sweet if over 3,000 sq ft it falls under the IBC. The IRC does not limit the size of the accessory structure it is just  out of the IRC prescriptive requirements.


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## righter101 (Jun 26, 2012)

Thanks Big Mac.  That summarizes things very well.  Makes sense to everyone here.  The only one that needs convincing is the ICC.  I was a bit shocked to see their response on their draft interpretation.

We have some large garages and barns here.  If you want to exceed the 3000 sq ft. we allow it under the IBC.

Thanks for the feedback.


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## righter101 (Jun 26, 2012)

mtlogcabin said:
			
		

> I see your point. It would be nice if they had said "aggregate floor area" if that is what the intent is.Basements have never been include in the area of a building.
> 
> Agree with Paul Sweet if over 3,000 sq ft it falls under the IBC. The IRC does not limit the size of the accessory structure it is just  out of the IRC prescriptive requirements.


Not sure what you mean by basements have never been included in the area of a building.  If they are below grade, they don't count as a story, but they definately are counted as area.

If I have a 2000 square foot house on top of a 2000 square foot finished basement, I have a 4000 square foot house.

Also, the IRC does limit the accessory size to 3000 square feet.  What I was trying to do is get people's opinion if that means per floor or total, as the ICC is preparing an opinion that it is per floor not aggegrate.


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## Big Mac (Jun 26, 2012)

Yes we get larger outbuildings here too, but they are reviewed using the IBC.  Sometimes even Appendix 'C', depending on use.


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## mtlogcabin (Jun 26, 2012)

> Not sure what you mean by basements have never been included in the area of a building. If they are below grade, they don't count as a story, but they definately are counted as area.


I was thinking of the IBC. You are correct the IRC is silent on defining building areas

506.5 Mixed occupancy area determination.

The total allowable building area for buildings containing mixed occupancies shall be determined in accordance with the applicable provisions of this section. A single basement need not be included in the total allowable building area , provided such basement does not exceed the area permitted for a building with no more than one story above grade plane .


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## High Desert (Jun 26, 2012)

righter101 said:
			
		

> Thanks Big Mac.  That summarizes things very well.  Makes sense to everyone here.  The only one that needs convincing is the ICC.  I was a bit shocked to see their response on their draft interpretation.


The ICC interpreation committees are made up of ICC members along with ICC staff.

Here are the members.

http://www.iccsafe.org/cs/Interp%20Committees/roster_RCIC.pdf


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## fatboy (Jun 26, 2012)

Our pal peach serves on one of the interp committees.......

Or did anyways.....after looking at the roster.


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## High Desert (Jun 26, 2012)

She's still on it.


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## Keystone (Jun 26, 2012)

IMHO, size should be left to zoning. Most state regs or local AHJ provide a limitation.


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## High Desert (Jun 26, 2012)

Keystone said:
			
		

> IMHO, size should be left to zoning. Most state regs or local AHJ provide a limitation.


I agree. We limit the size per zoning code.


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## Yankee (Jun 27, 2012)

I agree with big mac.

And size restriction per IRC and zoning size restrictions should both apply individually if need be.


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## brudgers (Jun 27, 2012)

IMO, the floor area  limits should be set by the structural limitations of the prescriptive methods within the IRC.

  Of which there are none.

  Any sort of arbitrary limit on accessory structures is scope creep of the sort which makes the I-codes SFL (So effing Lousy).

  Then again, I don't think an ICC committee ever passed up the chance to make the code worse through unwarranted additional complexity based on personal agendas.


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## righter101 (Jun 28, 2012)

brudgers said:
			
		

> IMO, the floor area  limits should be set by the structural limitations of the prescriptive methods within the IRC.   Of which there are none.
> 
> Any sort of arbitrary limit on accessory structures is scope creep of the sort which makes the I-codes SFL (So effing Lousy).
> 
> Then again, I don't think an ICC committee ever passed up the chance to make the code worse through unwarranted additional complexity based on personal agendas.


Given that the express a limit in the definitions, how would you interpret that section of the code.  Is it 3000 square feet of floor area (as the code reads) , or 3000 square feet of floor area per floor (as the ICC would like to interpret or explain.)???


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## brudgers (Jun 28, 2012)

righter101 said:
			
		

> Given that the express a limit in the definitions, how would you interpret that section of the code.  Is it 3000 square feet of floor area (as the code reads) , or 3000 square feet of floor area per floor (as the ICC would like to interpret or explain.)???


  In the least restrictive way that is not substantially unsafe.


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## righter101 (Sep 4, 2012)

THE ICC HAS SPOKEN.....

Regarding the proposed interpretation 23-12 that I brought up a few months ago, the ICC has issued their final interpretation.  It is contrary to the original draft and limits the size of an accessory structure (IRC) to 3000 square feet.  Here is the text.  It is available on the ICC website.

CHAPTER 2

DEFINITIONS

SECTION R202

2009 Edition

IRC INTERPRETATION 23-12

Issued 8-31-2012

RE_09_23_12

ACCESSORY STRUCTURE. A structure not greater than 3,000 square feet (279 m2) in floor area, and not over two stories in

height, the use of which is customarily accessory to and incidental to that of the dwelling(s) and which is located on the same lot.

● ● ● ● ● ● ● ● ● ●

Q: Is the floor area limitation of 3,000 square feet the combined floor area of all stories above grade plane plus any

basement floor area?

A: Yes. The floor area limitation is for the structure, not for each floor. The total floor area of the structure, including

the basement, is limited to 3000 square feet.


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## BSSTG (Sep 4, 2012)

brudgers said:
			
		

> I think that accessory structures should be left as part of zoning.  Putting size limits in the IRC is silly, IMO.


I agree. We did one where I used to work that was at least 15,000 sq ft. Party house and big garage. Wish I had one.

BS


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## Yankee (Sep 5, 2012)

BSSTG said:
			
		

> I agree. We did one where I used to work that was at least 15,000 sq ft. Party house and big garage. Wish I had one.BS


Goes to show why this restriction makes sense.


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## brudgers (Sep 5, 2012)

righter101 said:
			
		

> THE ICC HAS SPOKEN.....  Regarding the proposed interpretation 23-12 that I brought up a few months ago, the ICC has issued their final interpretation.  It is contrary to the original draft and limits the size of an accessory structure (IRC) to 3000 square feet.  Here is the text.  It is available on the ICC website.  CHAPTER 2 DEFINITIONS SECTION R202 2009 Edition IRC INTERPRETATION 23-12 Issued 8-31-2012 RE_09_23_12 ACCESSORY STRUCTURE. A structure not greater than 3,000 square feet (279 m2) in floor area, and not over two stories in height, the use of which is customarily accessory to and incidental to that of the dwelling(s) and which is located on the same lot. ● ● ● ● ● ● ● ● ● ● Q: Is the floor area limitation of 3,000 square feet the combined floor area of all stories above grade plane plus any basement floor area? A: Yes. The floor area limitation is for the structure, not for each floor. The total floor area of the structure, including the basement, is limited to 3000 square feet.


  The interpretation is non-binding.   Of course.


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## Big Mac (Sep 5, 2012)

It might, or might not be non-binding, but it is an accurate interpretation of the code as written.


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## Durant (Sep 7, 2012)

I find it interesting that a "definition" has become a code requirement.  Normally, if I am looking for a code requirement I am not inclined to look in definitions.  However, in 2006 the ICC changed the definition of Accessory Building to include the limitation of 3,000 sq. ft. in floor area in the definition and I find that limitation in no other part of the IRC.

And, in the 2009 IRC, it further states that "the use of which is customarily accessory to and incidental to that of the dwelling".

I recently was sent to final a 12,000 sq. ft. accessory building to a "proposed?" (construction not begun) residential dwelling, in an area zoned residential.  I'm new here and just adapting to the native mindset.  Inside this "residential accessory building" I was surprised to see 2,000 sq. ft. of framing for office space (according to the owner who accompanied me).  There is no plumbing, HVAC, or electrical to the building (remember, I am there to conduct a final inspection of a residential "accessory building").  This is an 80' X 150' X 20' high metal building.  The residential lot is 10 acres.  I halted the inspection (not knowing the local habits) and defered to the building official.  I think this is going to P&Z or board of adjustments.

I'm curious to see how the use of this structure is going to be considered "customaily accessory to and incidental to that of the "proposed" dwelling.


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## globe trekker (Sep 7, 2012)

> I think this is going to P&Z or board of adjustments.


Was the P & Z checked before the permit was issued? .


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## Yankee (Sep 19, 2012)

Durant said:
			
		

> I find it interesting that a "definition" has become a code requirement.  Normally, if I am looking for a code requirement I am not inclined to look in definitions.  However, in 2006 the ICC changed the definition of Accessory Building to include the limitation of 3,000 sq. ft. in floor area in the definition and I find that limitation in no other part of the IRC.And, in the 2009 IRC, it further states that "the use of which is customarily accessory to and incidental to that of the dwelling".
> 
> I recently was sent to final a 12,000 sq. ft. accessory building to a "proposed?" (construction not begun) residential dwelling, in an area zoned residential.  I'm new here and just adapting to the native mindset.  Inside this "residential accessory building" I was surprised to see 2,000 sq. ft. of framing for office space (according to the owner who accompanied me).  There is no plumbing, HVAC, or electrical to the building (remember, I am there to conduct a final inspection of a residential "accessory building").  This is an 80' X 150' X 20' high metal building.  The residential lot is 10 acres.  I halted the inspection (not knowing the local habits) and defered to the building official.  I think this is going to P&Z or board of adjustments.
> 
> I'm curious to see how the use of this structure is going to be considered "customaily accessory to and incidental to that of the "proposed" dwelling.


Definitions are a really important part of code requirements.


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## zigmark (Sep 19, 2012)

Yankee-

I would go one step further and say that the lack of more and better definitions is probably an area that code in general could be improved.  Use the topic of this very thread as the example.  Now, wether you agree or disagree that this code should regulate size of buildings or leave it to zoning the definition was what created the issue.  In many instances the lack of clearly defining a term within the body of the code becomes the issue.  Throw a State ammendment or two on top of that and you have a complete mess.  I realize there is always a dictionary to default but many times that misses the mark of the context of the issue and creates even more uncertainty.  So we ask for an interpretation as was the case here with the OP and we get an initial enterpretation that is not even close to how the majority of us were enforcing it.  Granted, they got it right in the end and I applaud them for that, but what if righter hadn't made an issue of it?

Personally I still feel limitations on accessory buildings should be left in zonings hands but we have an interpretation now.

ZIG


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