Steel Stud Framing Without Continuous Insulation

[goodwork]

The Building in question:

Type V-B Construction
Cold Formed Steel Stud Framing
3 story
R-2 Apartments
IECC 2015
Climate Zone 4A

Is it possible or even legal to build a CFS framed building with no Continuous Insulation?
It's not prescriptive, of course, but can you energy model your way out of it?
The thermal bridging and potential moisture issues aren't ideal for sure, but if you had to do it, could you?

Thanks in advance.

 

[RLGA]

Yes, you can use either the U-factor alternative method (Section R402.1.4) or the total UA alternative method (Section R402.1.5).

 

[goodwork]

Yes, you can use either the U-factor alternative method (Section R402.1.4) or the total UA alternative method (Section R402.1.5).

Interesting, thanks. Question: does this alternative method apply to IBC residential buildings, or just IRC projects?

 

[jc_ks]

It's interesting, the residential and commercial sections of the IECC do not break the same way that the IBC/IRC do. In the IECC the Residential section applies to single/dual family as well as apartments 3-stories or less in height. Everything else would be under the commercial energy code.

 

[Penguin87]

The Building in question:

Type V-B Construction
Cold Formed Steel Stud Framing
3 story
R-2 Apartments
IECC 2015
Climate Zone 4A

Is it possible or even legal to build a CFS framed building with no Continuous Insulation?
It's not prescriptive, of course, but can you energy model your way out of it?
The thermal bridging and potential moisture issues aren't ideal for sure, but if you had to do it, could you?

Thanks in advance.

No, the max R value you can get with steel studs is around R-9 IIRC. You either need continuous insulation or a second furring wall.

No amount of finagling with Comcheck tradeoff energy modeling will get you anywhere close to passing on any strucutre unless you have a very tiny amount of metal stud framing for your exterior wall.

Believe me, I have ran the calcs.

In any case, now you know why light commercial framed buildings are done with wood framing and not metal stud.

 

[Penguin87]

To add to above:
A metal stud wall has a U value of ~0.11. Max U-value for a residential building per table R4.02.1.4 is U-0.060 so it will fail by a huge margin.
The equivalent min R value is R-20.