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IECC 2012 - Above Grade Wall Frame Construction

fj80

fj80

Sawhorse
Joined
Jan 18, 2016
Messages
230
Location
Virginia
Project background: Extensive renovation to historic two-story building including addition of two new stories above the existing two. Mixed occupancies: 1st floor restaurant, 2nd floor offices, 3rd & 4th floors will be residential units. IBC 2012 and IECC 2012. Location: Washington DC.

I'm trying to figure out the above grade wall construction I need to provide for two scenarios, that meet the IECC 2012 building envelope requirements:

Scenario 1) Existing two story masonry walls, the side walls of which are party walls right up against the adjacent buildings at the property line. What wall construction do I use to get proper insulation? Since they are party walls I have to insulate on the inside of the existing masonry walls. Where can I find the appropriate wall construction?

Scenario 2) New stories 3 and 4 will be metal framed exterior walls with a thin brick veneer on the outside. Per Table C402.2, I know I am Climate Zone 4A, I need R-13+ and R-7.5 continuous insulation on the exterior side of the studs. Where do I find the appropriate wall construction/composition to meet the energy requirements and for this condition?
 
Fire rating for the party wall only needs to be 1 hour, right? Per IBC 2012 Table 602 (I'm occupancies R and B.) What fire resistance construction method(s) would work for this type of wall?
 
$ = = $

fj80,

To get an approved type of fire rated assembly between

different Occupancy Groups, ...you might start with the

Underwriters Laboratories web site, and search for an

assembly for your application........See this link from this

Forum:

http://www.thebuildingcodeforum.com/forum/forum/other-topics/useful-links/17793-u-l-product-specifications

Also, according to Section 402.1.1 from the `12 IEEC

...the wall(s) insulation will need to comply with the

requirements in ANSI \ ASHRAE \ IESNA 90.1.

See Note " a" after Table C402.2 that directs you to

the listed Standards above for a description of the

assemblies.

According to the DOE web site, persons can use

ComCheck to check for compliance of their projects.

See this link from the DOE:

https://www.energycodes.gov/adoption/states/washington-dc

There is a link on the DOE website to download ComCheck !

= $ $ =
 
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Anybody know what type of wall construction and insulation I need for scenario 1, at the existing exterior masonry walls? Can I just add furring and insulation to the inside of the masonry walls?
 
% ` ` %

fj80,

Have you determined for certain that the existing "Party Wall"

is a true fire rated wall [ in accordance with Section 706.1.1,

in the `12 IBC ]........Also, see Table 721.1(2), at the Material

column, ...# 3, for fire resistance of various walls and partitions.

% ` ` %
 
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The existing party wall is solid brick, 11" thick, which per Table 721.1(2) gives it a fire rating of more than 4 hours. Since table 706.4 requires a 3 hour rating for A, B occupancies, the existing brick wall should be adequate for the fire rating requirement. Is my logic solid there?
 
& + & +

Seems so !.......The 11" thick wall should provide some type of thermal R-value

as well, so IMO, ...Yes, you could simply frame on the interior side of the

existing masonry wall, add some thermal \ acoustic insulation, and it should be

compliant.

+ & + &
 
Don't know if it would help with the minimum requirements but did Wash., D.C. adopt the administrative section or has similar language?

As a reminder new construction would the new addition; not reconstruction and alterations made to the existing building.

C101.4 Applicability.

Where, in any specific case, different sections of this code specify different materials, methods of construction or other requirements, the most restrictive shall govern. Where there is a conflict between a general requirement and a specific requirement, the specific requirement shall govern.

C101.4.1 Existing buildings.

Except as specified in this chapter, this code shall not be used to require the removal, alteration or abandonment of, nor prevent the continued use and maintenance of, an existing building or building system lawfully in existence at the time of adoption of this code.

C101.4.2 Historic buildings.

Any building or structure that is listed in the State or National Register of Historic Places; designated as a historic property under local or state designation law or survey; certified as a contributing resource with a National Register listed or locally designated historic district; or with an opinion or certification that the property is eligible to be listed on the National or State Registers of Historic Places either individually or as a contributing building to a historic district by the State Historic Preservation Officer or the Keeper of the National Register of Historic Places, are exempt from this code.

C101.4.3 Additions, alterations, renovations or repairs.

Additions, alterations, renovations or repairs to an existing building, building system or portion thereof shall conform to the provisions of this code as they relate to new construction without requiring the unaltered portion(s) of the existing building or building system to comply with this code. Additions, alterations, renovations or repairs shall not create an unsafe or hazardous condition or overload existing building systems. An addition shall be deemed to comply with this code if the addition alone complies or if the existing building and addition comply with this code as a single building.

Exception: The following need not comply provided the energy use of the building is not increased:

1. Storm windows installed over existing fenestration.

2. Glass only replacements in an existing sash and frame.

3. Existing ceiling, wall or floor cavities exposed during construction provided that these cavities are filled with insulation.

4. Construction where the existing roof, wall or floor cavity is not exposed.

5. Reroofing for roofs where neither the sheathing nor the insulation is exposed. Roofs without insulation in the cavity and where the sheathing or insulation is exposed during reroofing shall be insulated either above or below the sheathing.

6. Replacement of existing doors that separate conditioned space from the exterior shall not require the installation of a vestibule or revolving door, provided, however, that an existing vestibule that separates a conditioned space from the exterior shall not be removed,

7. Alterations that replace less than 50 percent of the luminaires in a space, provided that such alterations do not increase the installed interior lighting power.

8. Alterations that replace only the bulb and ballast within the existing luminaires in a space provided that the alteration does not increase the installed interior lighting power.
 
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Why would the party walls need to be insulated? The IECC requires the thermal insulation at the building thermal envelope, which it defines as the boundary separating conditioned spaces from unconditioned spaces... assuming that the spaces in the adjacent properties are conditioned, the party wall doesn't meet that definition, and therefore meeting the insulating requirements is not necessary.

Now, wanting to add acoustic insulation might be desirable...
 
Why would the party walls need to be insulated? The IECC requires the thermal insulation at the building thermal envelope, which it defines as the boundary separating conditioned spaces from unconditioned spaces... assuming that the spaces in the adjacent properties are conditioned, the party wall doesn't meet that definition, and therefore meeting the insulating requirements is not necessary.Now, wanting to add acoustic insulation might be desirable...
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Existing two story masonry walls, the side walls of which are party walls right up against the adjacent buildings at the property line
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706.1.1 Party walls.

Any wall located on a lot line between adjacent buildings, which is used or adapted for joint service between the two buildings

I am not sure you have a "party wall" by your description. The side walls should be part of the adjacent buildings in order to be a "party wall". If the adjacent building is removed or abandoned and there is no heat on the other side of that wall then the building thermal envelope is established along that wall. Think of a house with an attached un-heated garage. I suggest you insulate that wall the same as the other exterior walls.
 
I agree with ADAguy. Thank you all very much. My building is within a locally designated historic district so I believe we are not required to comply with the IECC for the existing portion of the building, just the two new stories. mtlogcabin is correct- I do not have true party walls, just separate walls for each building, built right up against each other. Looks like we should insulate them just as best practice, even if IECC doesn't apply here.
 
Oh really? Meaning even adding two new floors would not need to comply with IECC? Is there a section in the code that states that?
 
Oh really? Meaning even adding two new floors would not need to comply with IECC? Is there a section in the code that states that?
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To my knowledge only to the extent that the historical (appearance) requirements are not affected; such as exterior lighting (C405.1, C406, C405.6.2); equipment and protected interior historical features.
 
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