Anchoring Wood to a Steel I-Beam
Forget about packing the web; fasten wood to the top, and hang the floor framing with top-mount joist hangers.
Synopsis: Steel beams can carry much more weight than solid or engineered lumber, so they’re often used in home building. But anchoring wood to steel can be time-consuming. John has replaced the most common method — packing the web with lumber — with a far faster method incorporating top-mount joist hangers. By bolting a piece of lumber to the top flange of the I-beam and nailing the joist hangers to it, you can reduce the amount of lumber you use, the number of holes you drill, and the number of bolts you install. And top-mount joist hangers require fewer nails, too.
Modern floor plans are trending toward wide open spaces. Despite advances in engineered-wood beams, there are times when something stronger is needed. Many carpenters shy away from steel because fastening lumber to steel can be tricky. Cutting a steel beam on site is even trickier. Sometimes, though, a steel I-beam is the best choice. Structural steel costs less than comparable LVLs, is strong, and is available from local suppliers. If you order it to the right size with fastener holes punched, your only challenge will be attaching the lumber.
Steel has a few limitations
Although a piece of steel carries a larger load over a longer span with less depth than any other building material, steel has some disadvantages. First, it’s very heavy. You need to make sure you can get it to where it needs to go, either with humans or with a machine. Second, you won’t find steel span charts in a codebook; steel usually needs to be sized by an engineer. Steel should be protected from moisture to prevent rust and deterioration. Also, a steel beam will fail much more quickly and catastrophically than an equivalent wood beam in a fire.
Top-mount joist hangers are…