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RE: Sill plate washer - 2x2 or 3x3?

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This happened in the Provisions Update Committee voting and resolution of the BSSC. The FEMA 450 Commentary (2003 NEHRP Commentary), Section and on page 237 discusses that there was splitting in the sill plate in testing and observed in earthquakes that the larger plate washers intended to mitigate. I recall that debate as "stimulating".

Harold Sprague

From: "Haan, Scott M." <HaanSM(--nospam--at)>
Reply-To: <seaint(--nospam--at)>
To: <seaint(--nospam--at)>
Subject: RE: Sill plate washer - 2x2 or 3x3?
Date: Tue, 6 Jul 2004 11:27:58 -0800

2003 IBC 2305.3.10 only mentions 2x2x3/16 plate washers. I remember seeing larger washers for wider sill plates in the NEHRP Recommended Criteria....

-----Original Message-----
From: Dmitri Wright [mailto:dmitri(--nospam--at)]
Sent: Tuesday, July 06, 2004 10:06 AM
To: Seaint
Subject: Sill plate washer - 2x2 or 3x3?

Dear List:

For those who are working in areas adopting the IBC/IRC, here is an issue you may be interested in. It seems rather trivial, but I bet it will cause plenty of bickering between the contractor/inspector/engineer/owner.

The original question:

I noticed in the errata to the IRC 602.11.1 that the sill washers that used to be 2"x2" are now required to be 3"x3". I did not see a similar errata for the IBC 2305.3.10 which calls for a 2"x2" sill washer. Was this the intent of the ICC, and if so, why?

Thank you for clarifying this.

The response:

We are pleased to provide you with the following opinion. It should be noted, however, that the final interpretation is the responsibility of the local building official.

In the IRC, the 2 x 2 x 3/16 washer size was changed by errata to 3 x 3 x ¼ based on code change RB 82-02, submitted by the Building Seismic Safety
Council & dealing strictly with coordinating the     IRC provisions with
2000 NEHRP Section 12.5.3. There was no similar code change to the IBC provision, so it remained unchanged and we [ICC staff] have no basis for an
errata to the 2003 IBC on         this issue.

Subsequently, the Utah Chapter of ICC submitted code change S83-03/04 which changes the plate washer size to 3 x 3 x ¼ in IBC Sections 2305.3.10
[engineered shear walls] and                     2308.12.8 [conventional
construction]. This approved change will appear on the 2004 Supplement to the International Codes available later this month. Supplement provisions do
not automatically affect    the application of 2003 IBC, unless they are
incorporated as modifications through local adoption of the code.

So, it looks like 3x3 is probably the safe bet, but good luck explaining to the contractor who probably bought 5 cases of 2X2's before the steel prices went up.

Dmitri Wright, PE
Progressive Consultants Inc.

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