Author Topic: STC and IIC Design guidelines for new construction – Luxury Condominiums  (Read 7794 times)


  • Guest
I realize that this is a subjective question but is there any guideline or benchmark STC and IIC rating for “Luxury Condominiums”? I understand that the baseline minimum sound transmission requirements for new construction apartments in my area are based on the local building code:

STC not less than 50 per ASTM E 90 (Section 1207.2, 2003 IBC)
IIC not less than 50 per ASTM E492 (Section 1207.3, 2003 IBC)

Is there a publication or agency that might suggest a target STC and IIC for Luxury Condominiums instead of just publishing baseline minimums? I appreciate that there is a potentially huge cost difference between an IIC rating of 50, 55, 60 and higher but would be curious if any guidelines beyond building code minimums existed; especially given the potential for litigation.

Thanks in advance for any guidance you may be able to provide.

Best Regards,


  • Guest
Unfortunately, there aren't. 

As you've said, STC/IIC of 50 are the bare minimums and most developers will only begrudgingly meet that. 

The cost difference between STC 50 and 60 is not huge, but it does eat into the profit margin and builders aint gonna shoot for it unless it's the law.  Unlikely STC 60 will ever be the legal minimum. 

There aren't many 'enlightened' builders out there - if there were, we'd see a lot more buildings built out of concrete - 8-12" slabs between each unit, with additional steel/wood stud wall framing, insulation and resiliently hung ceilings.  If they built 'em that way, a between-unit STC of 70 would be fairly easy to achieve.   


  • Guest