The other week, a friend of mine shared that she was looking for a solution to a spider-riddled back porch. With Seattle’s first big rain in months—and lots of misty days in the future—she noticed another back-porch issue to tackle: slippery steps. My friend told me her parents dealt with this problem at their home by putting down strips of non-skid tape (which is nothing more than black tape with texture on it). She disliked the way the non-skid tape looked right off the bat, and how it began to peel up and look tacky over time (it didn't last after a month of rain). Needless to say, my friend wanted to go a different route.

Enter the GacoDeck Kit. The Gaco Western company makes a great, non-skid, waterproof coating for balconies and rooftops. While we could use GacoDeck on our stair project, we zeroed in on one component of the GacoDeck system—the GacoGrip granules, which can be purchased separately. The GacoGrip product is nothing more than finely ground walnut shells, which can be mixed into a coating to provide a non-skid surface. It's kind of like beach sand, but walnut shells won't rub off or grind into paint or finishes—and that's a big advantage when your goal is to rainproof stairs.

My friend didn’t want to paint over the natural wood on her porch, so I came up with a GacoDeck-inspired idea to mix walnut shells in to a polyurethane finish. I’m going to guess that my solution won’t hold up the same way GacoDeck would, but for me—even if you’re refinishing the porch every season, it’s totally worth it for the traction and aesthetic benefits.

For these stairs we weren’t interested in doing a large-scale project, and I love our simple, relatively quick fix.

gacogrip and daly's stain

Step 1: Prep the stairs

Start with a clean, dry surface. These stairs had recently been stained with Penofin Verde wood stain (in the color Bitterwood), so I just swept off any loose debris and wiped down each step before I got started.

If you’re starting from scratch, check out our blog on how to refinish a deck for a full how-to (and some insider tips).

cleaning stairs

bare stairs for rainproofing

wiping off stairs

Step 2: Make the walnut polyurethane solution

Once the deck is clean, make your walnut polyurethane solution.

The ratio of walnut shells to finish is 1:10. Pour one ounce of walnut shells followed by 10 ounces of Daly’s SeaFin AquaSpar waterborne polyurethane into a mixing container. I used a Mix N' Measure plastic container that has ounce measurements already printed on the tub. I chose Daly’s SeaFin AquaSpar because it’s an exterior polyurethane that Daly’s designed for marine use. It’s made for wood finishes on boats, which means it’s durable and designed to come into contact with lots of water.

Mix with a stir stick, and continue stirring frequently throughout the application.

notepad and smartphone

rainproofing materials

pouring daly's satin stain

pouring Gacodeck walnut shells

stirring gacodeck for rainproofing

Step 3: Apply the solution

With a clean synthetic brush, apply the walnut polyurethane solution. The most important part of this step is to make sure you’re constantly stirring the mixture because the walnut shells naturally settle to the bottom of the polyurethane.

For best results, read through the application instructions on the polyurethane container, paying particular attention to the warning not to over-brush.

apply rainproofing to stairs

rainproof stairs diy

painting on rainproofing for steps

Step 4: Let dry and reapply

Allow the finish to dry for four hours before putting down another coat. For the remaining coats (Daly’s recommends a minimum of three applications), assess whether you want to include more walnut shells or just apply the polyurethane finish over the walnut shells already on the stairs. 

For this project, I did one coat with the walnut shells and then added the remaining applications with just the polyurethane finish.

drying steps with rainproofing

Step 5: Let dry before use

Allow the finish to fully dry before walking on the stairs. Re-apply seasonally (or as needed).

I’m really happy with how subtle and effective this solution is. One might argue that it’s even more effective than a strip of tape because it’s covering the whole surface area of the stairs. There was definitely a noticeable difference in traction, which has been verified by all of my friend’s house guests, who commented about the tread. Hopefully, you’ll have the same results!

how to rainproof steps

For more weather-proofing project ideas, check out this guide to preventing fire pit rust or our easy tutorial for refreshing a mossy cedar fence.