Thread: H clips

When should H clips be used and and when are they exempt from use. When were they required per code?


Jim Murphy

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Originally Posted by JIM MURPHY

When should H clips be used and and when are they exempt from use. When were they required per code?


Jim Murphy

I really do not know of any code requirement for "H" clips. They are used on the horizontal runs and essentially stiffen and space the sheathing.

http://www.tecotested.com/techtips/pdf/tt_edgeclips

Teco is an independent third party tester.
Hope this helps!

Originally Posted by JIM MURPHY

When should H clips be used and and when are they exempt from use. When were they required per code?

Jim,

Depends on your definition of "should".

"H" clips "should" never be used, instead, thicker plywood/OSB with a higher span rating "should" be used.

"H" clips are used to allow the use of otherwise thinner and under rated sheathing and push the boundaries of what "good building practices" "should" be. Think of their use as 'value engineering' where 'the value is engineered out', leaving you with minimum construction practices.

The clips are also used in order to speed up the building process while at the same time maintaining proper gaps between panels. They are one of those ubiquitous items that are fast to work with thereby speeding up some process and that any dumb dumb can work with to maintain a "standard" of one type or another without even having to know why. Sometimes, that's not a good thing.

clips are mandatory for those who can't remember to leave the proper spacing

It would seem that we all have opinions about whether or not H clips are the lazy man's way out or an inferior construction method. It seems to me that we should be more concerned with Industry Standards and Codes than opinion if we want to give factual information and protect our E&O record. The actual answer to the original question is found in the 2003 International Residential Code (and all other versions):

TABLE R503.2.1.1(1)
ALLOWABLE SPANS AND LOADS FOR WOOD STRUCTURAL PANELS FOR ROOF AND SUBFLOOR SHEATHING AND COMBINATION SUBFLOOR UNDERLAYMENT

a,b,c

The column titled Allowable Spans shows a footnote (d). Footnote (d) reads as follows:

d. Lumber blocking, panel edge clips (onemidway between each support, except two equally spaced between supportswhen span is 48 inches), tongue-and-groove panel edges, or other approved type of edge support.

In addition, the American Plywood Association (APA) has some great information on this and other topics related to engineered wood products on their website:
Publications Featuring Building Basics | APA - The Engineered Wood Association

Scroll down to the 22nd item on the page, entitled:

Builder Tips: Proper Installation of APA Rated Sheathing for Roof Applications

Step-by-step instructions for roof sheathing installation. Updated December 2008. (Form N335 - 2 pages)

All of their literature is available as free downloadable pdfs.