Contact Us   |   Sign In   |   Register

Log in

Download Final PDF

Interpretation #8573

Original Request

  • Requested By: Shane Kittendorf
  • Requester E-Mail: skittendorf@capfla.com
  • Code Version: 2021
  • Code: RESIDENT
  • Code Description:
  • Chapter:
  • Section: R302.2.4
  • Topic: Townhouse Fire Separation

  • Question: 1. Is it the intent of the FBC - Residential volume, Section R302.2.4 Structural Independence, Exception(s), to allow for the support and anchoring of the structural members of the roof and floor to the common wall?

    2. Is a Townhouse Unit under the residential code R302.2.4 considered structurally independent if the common wall has roof and floor structural members supported on ledgers and secured in buckets anchored to the common wall from both townhouse units?

    3. If the answer is no to either question listed above, would that mean that the Townhouse units meet compliance with the FBC-Building Code?

Answer:

Yes and yes; We have traditionally viewed structural independence to mean that either side of the common wall could have complete structural collapse without affecting the common wall and the other side. A floor truss system attached to the common wall by a bolted on ledger and/or bucket has typically been viewed as allowing such collapse and therefor has been approved. Without a clear definition of "structurally independent" in the Residential Code we can look at the Building Code for guidance, Particularly, 706.4.1.2 and 706.2 "Structural stability. Fire walls shall be designed and constructed to allow collapse of the structure on either side without collapse of the wall under fire conditions. Fire walls designed and constructed in accordance with NFPA 221 shall be deemed to comply with this section."
On 10/13/2021 at 2:07 PM

Commentary:

The traditional view of structural independence appears to still be correct. It is interesting that the 2014 FBC Residential section R302.2.4 "Structural Independence" had 5 exceptions instead of 4. The 5th exception that was removed from the code stated " Townhouse separated by a common 1-hour fire resistant rated wall as provided in section R302.2" It may have been removed as it could have been interpreted to mean no structural independence was required at all.