What percentage of a Wooden I Beam stem can be removed and still be considered safe for construction?

• A. 70%
• B. 90%
• C. 80%
• D. 100%

Answer: (B)

Wooden I-beams derive most of their bending strength from the flanges, while the thin web (stem) mainly handles shear and helps keep the beam connected and stable. In typical construction practice, you can make openings or remove portions of the stem for installations, but you must leave enough of the web intact to transfer shear and maintain overall stability. The guideline reflected here is that you can remove up to about 90% of the stem and still be considered safe, as long as you stay within manufacturer recommendations and keep critical areas intact. Leaving roughly 10% of the stem ensures the web continues to function adequately for load transfer. Removing all of it would collapse the web’s role and is not safe, and removing 70% or 80% is not as permissive as the maximum commonly allowed.