Can I drill more than 3 holes in a TJI® joist?


Although our Forte® software does not currently allow more than 3 holes per span, the published hole charts do not prohibit more holes in a TJI® joist span.  Once the minimum distance from either end is determined, holes can be cut/drilled along the span (maintaining proper hole-to-hole spacings) until the minimum distance from the OTHER end of the span is reached.

Note that both end support requirements (Table A) and intermediate or cantilever support requirements (Table B) must be followed when applicable.  See page 9 in the TJI® Joist Specifier's Guide or page 1 of the Framer's Pocket Guide.

The designer should also be aware that if more than three holes are cut in a single joist,the stiffness and floor performance decreases in proportion to the amount of web area removed.

For joists that are not uniformly loaded or otherwise do not fit the parameters of the published hole charts, please contact Weyerhaeuser Technical Support

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