I'm in the middle of replacing the wood on a bridge that spans a stream in my driveway. The bridge measures about 14 feet wide by 28 feet long and is supported by four steel I-beams set on concrete abutments. Currently, the decking consists of 5x8s on top of the I-beams, allowing for 4x6s to attach perpendicularly to form the bridge surface, with 2x10 runners running parallel to manage weight and wear. I'm replacing all the lumber with rough cut, pressure-treated wood due to our humid environment and occasional flooding. My main concern is how to effectively fasten the pressure-treated wood to the steel beams without causing issues. The existing setup uses through bolts with a tar paper barrier. I plan to use stainless steel hardware to mitigate galvanic corrosion and need suggestions for an effective barrier. For attaching the 4x6s and 2x10s, I'm considering hot dipped galvanized spikes since they won't touch the steel. Does this plan seem sound?
1 Answer
I recommend using EPDM for that barrier! It's affordable, durable, and effective. Just buy some rolls of EPDM roofing and cut them into strips that fit your pressure-treated wood. We've used it on similar projects and had good results.
Great idea! EPDM is a solid choice for this type of application.