I have a new home where the walls are framed with 2x4s and are insulated with batt. This provides at most R-13 in theory, while current code requires either R-20 or R-13+5 (R-5 from continuous insulation).

The builder has confirmed there is a house wrap and that there is foam in the siding on the house, but there is no type of rigid foam board between the walls and the siding.

I wanted to confirm that there is no way that siding could meet the continuous insulation requirement since siding can clearly come off and on in parts where air can get through.

The lower half of the wall is brick - does brick provide any type of actual insulation or is it the same as siding?

Is there anything else the builder could have done here to get the theoretical minimum r-value from code using 2x4 framing? Want to be sure everything is clear before I start asking for remediation.

  • I thought 2x6 was required for residential, it has been in my area for decades. You can only put so much insulation in a 3-1/2” cavity. – Ed Beal Oct 31 '19 at 15:52

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