FAQ: Slippery boardwalks and bridges

Recommendations for anti-slip on wood surfaces.

by American Trails Staff

A trail in the redwoods could become slippery when wet; photo by Kimball Schmidt

How do you fix a slippery boardwalk or metal truss/timber deck bridges Wood can become slippery when wet due to algae, mold and mildew. Signs can be posted but there are more pro-active approaches to dealing with future slip-and-fall concerns.

What options are there to fix this problem? Is there some type of clear coating paint with grit to paint on top of the wood (in strips)? What else is there that can be done to prevent re-building a whole new boardwalk?

Remove the mold and mildew

If the slippery boardwalk has a greenish look to it, the cause is likely mold and mildew growing on it. Here's a few steps to clean the boardwalk:

1) The mold/mildew will need to be killed first using a 1 part Chlorox to 4 parts water solution. This solution can be sprayed to cover the entire wood board area, using caution not to overspray. The surface should be wet, but not dripping over the edges. This can be done using a 2 gallon hand sprayer or possibly with a tank mounted on an ATV.

2) If possible, pressure wash/scrub with a stiff brush the mold/mildew off the surface of the boards. You may want to do this step in conjunction with spraying the Chlorox solution.

3) Respray the boards with the Chlorox solution following the instructions above and let dry.

4) Use a heavy duty wood sealer to seal the boards which should stop the mold/mildew from being able to access the wood as a place to grow and reproduce. Sealer probably should be a double coat or do one coat with plans to do a recoat next year. Once the two coats are in place, and working, you should only need to recoat every 2-3 years.

Apply paint with a grit substance

If you plan to paint, you will still need to do this type of cleaning prior to painting.

Paint on a marine-grade anti-slip decking product for wooden boards especially prone to becoming slippery. This product contains sand or aggregates suspended in a paint or resin, which you can apply with a paint roller with a thick-nap roller cover. For safety measures on steps, purchase and apply self-adhesive strips containing a coarse grit surface to dried steps at their front edges.

Also, check with your state agencies to see what their procedures are that are specific to your region.

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