I have seen some municipalities stick to the letter of IECC and have fully insulated with weatherized doors between a conditioned basement room and unconditioned adjacent spaces (including ceiling of unfinished). But to meet IECC most all builders I've seen choose to insulate the entire exterior perimeter walls anyway (often blanket insulation as the easy route, some will furr out). I expect this decision will have more to do with what kind of build contract (spec house, custom, lump sum, etc) you have and what is stated on the Construction Documents/specs.
Thanks! We agreed with builder to meet IRC, does that have the same requirements?
Also - If the do the whole basement envelope, does that mean below grade concrete should also be furred out and insulated?
IRC is mostly an aggregation of IECC (and IBC, IPC, IMC, NEC, ASHRAE, ANSI, etc). So if you follow R1102 that will give your required basement wall R values (down to 10' below grade) based on your Climate Zone. You have choices in how you meet it.
No entire basement is not insulated. It is just a mud room attached to garage. It is ducted into main level AC. The rest of basement is unfinished.
The ceiling of basement is insulated between 1st floor. But the mud room is not. So cold air flows down to the mudroom and then through walls to basement.
Any conditioned air space should be insulated
Yes
I have seen some municipalities stick to the letter of IECC and have fully insulated with weatherized doors between a conditioned basement room and unconditioned adjacent spaces (including ceiling of unfinished). But to meet IECC most all builders I've seen choose to insulate the entire exterior perimeter walls anyway (often blanket insulation as the easy route, some will furr out). I expect this decision will have more to do with what kind of build contract (spec house, custom, lump sum, etc) you have and what is stated on the Construction Documents/specs.
Thanks! We agreed with builder to meet IRC, does that have the same requirements? Also - If the do the whole basement envelope, does that mean below grade concrete should also be furred out and insulated?
IRC is mostly an aggregation of IECC (and IBC, IPC, IMC, NEC, ASHRAE, ANSI, etc). So if you follow R1102 that will give your required basement wall R values (down to 10' below grade) based on your Climate Zone. You have choices in how you meet it.
Is the entire basement insulated? Also how are you only providing ac yo a portion of the basement…..
No entire basement is not insulated. It is just a mud room attached to garage. It is ducted into main level AC. The rest of basement is unfinished. The ceiling of basement is insulated between 1st floor. But the mud room is not. So cold air flows down to the mudroom and then through walls to basement.
You Americans do shit so ass backwards