Effective Date of Rule: July 1, 2007.
Purpose: To amend the 2006 International Residential Code, WAC 51-51-0404 related to lateral support for basement foundation walls.
Citation of Existing Rules Affected by this Order: Amending WAC 51-51-0404.
Statutory Authority for Adoption: RCW 19.27.074 and 19.27.020.
Other Authority: Chapters 19.27 and 34.05 RCW.
Under RCW 34.05.350 the agency for good cause finds that immediate adoption, amendment, or repeal of a rule is necessary for the preservation of the public health, safety, or general welfare, and that observing the time requirements of notice and opportunity to comment upon adoption of a permanent rule would be contrary to the public interest.
Reasons for this Finding: The state building code council (council), based on the following good cause, finds that an emergency affecting the general welfare of the state of Washington exists. The council further finds that immediate amendment of a certain council rule is necessary for the public welfare and that observing the time requirements of notice and opportunity to comment would be contrary to the public interest.
The declaration of emergency affecting the general welfare of the state of Washington is based on the following findings:
The council adopted the 2006 edition of the International Residential Code (IRC) effective July 1, 2007. The IRC regulates the construction of one and two family residences and townhouses. The 2006 IRC contains new provisions related to a requirement for lateral restraint at the top of concrete and masonry foundation walls, which the council initially amended to require only in the case of walls over five feet in height. Upon further review, the council determined the new requirement would still impose significant and potentially unnecessary attachment and blocking requirements to basement walls that exceed five feet, and would cause unnecessary economic burden on the building industry in Washington.
There has been considerable debate on this issue both in the state and at the national level. Council appointed a technical advisory group to review the issue. The group reported back to the council that there have been no failures of foundation walls in Washington state built under the previous requirements. The failures that have occurred can be traced back to other faulty construction practices. The technical advisory group felt there was no technical substantiation for the increase in cost associated with the new requirements for lateral restraint of foundation walls. At the final action hearing of the International Code Council, the membership also concurred with Washington's technical advisory group and voted to remove these additional provisions from the national model code.
The council concluded that it is in the best interest of the general welfare of the state of Washington to amend the provisions related to lateral restraint of foundation walls in Section R404 of the IRC with the language adopted by the membership of the International Code Council for inclusion in the 2009 edition of the IRC.
Number of Sections Adopted in Order to Comply with Federal Statute: New 0, Amended 0, Repealed 0; Federal Rules or Standards: New 0, Amended 0, Repealed 0; or Recently Enacted State Statutes: New 0, Amended 0, Repealed 0.
Number of Sections Adopted at Request of a Nongovernmental Entity: New 0, Amended 1, Repealed 0.
Number of Sections Adopted on the Agency's Own Initiative: New 0, Amended 0, Repealed 0.
Number of Sections Adopted in Order to Clarify, Streamline, or Reform Agency Procedures: New 0, Amended 0, Repealed 0.
Number of Sections Adopted Using Negotiated Rule Making: New 0, Amended 0, Repealed 0; Pilot Rule Making: New 0, Amended 0, Repealed 0; or Other Alternative Rule Making: New 0, Amended 1, Repealed 0.
Date Adopted: June 8, 2007.
John P. Neff
AMENDATORY SECTION(Amending WSR 07-01-090, filed 12/19/06, effective 7/1/07)
WAC 51-51-0404 Section R404 -- Foundation and retaining walls.
R404.1 Concrete and masonry foundation walls. Concrete and masonry foundation walls shall be selected and constructed in accordance with the provisions of Section R404 or in accordance with ACI 318, ACI 332, NCMA TR68-A or ACI 530/ASCE 5/TMS 402 or other approved structural standards. When ACI 318, ACI 332 or ACI 530/ASCE 5/TMS 402 or the provisions of Section R404 are used to design concrete or masonry foundation walls, project drawings, typical details and specifications are not required to bear the seal of the architect or engineer responsible for the design, unless otherwise required by the state law of the jurisdiction having authority.
Foundation walls that meet all of the following shall
be considered laterally supported:
1. Full basement floor shall be 3.5 inches (89 mm) thick concrete slab poured tight against the bottom of the foundation wall.
2. Floor joists and blocking shall be connected to the sill plate at the top of the wall by the prescriptive method called out in Table R404.1(1), or; shall be connected with an approved connector with listed capacity meeting Table 404.1(1).
3. Bolt spacing for the sill plate shall be no greater than per Table R404.1(2).
4. Floor shall be blocked perpendicular to the floor joists. Blocking shall be full depth within two joist spaces of the foundation wall, and be flat-blocked with minimum 2-inch by 4-inch (51 mm by 102 mm) blocking elsewhere.
5. Where foundation walls support unbalanced load on opposite sides of the building, such as a daylight basement, the building aspect ratio, L/W, shall not exceed the value specified in Table R404.1(3). For such foundation walls, the rim board shall be attached to the sill with a 20 gage metal angle clip at 24 inches (610 mm) on center, with five 8d nails per leg, or an approved connector supplying 230 pounds per linear foot (3.36 kN/m) capacity.
10-INCH MASONRY FOUNDATION WALLS WITH REINFORCING
WHERE d > 6.75 INCHESa
[Statutory Authority: RCW 19.27.074, 19.27.020, and chapters 19.27 and 34.05 RCW. 07-01-090, § 51-51-0404, filed 12/19/06, effective 7/1/07.]