Expanding a deck from a basic rectangle to a multi-level setup is a massive undertaking, especially when dealing with the wet PNW weather. One thing I learned the hard way is that when you increase your footprint to fifty-seven feet, managing water runoff becomes your biggest hurdle. I used SkyLifts for the roof extension to get extra height and airflow, wich helps prevent rot on the house siding. If you're building a custom planter into the framing, don't let water just drip through the boards. I ran a rain chain through the planter that connects to a hidden gutter pipe under the deck. It’s a clean look and keeps the ground from becoming a swamp. Even with a shallow frost line, spend the extra time on those sono tubes for the heavy pergola posts. It’s much more stable than pier blocks when the wind picks up. Give yourself a physical break before you start the skirting. That finish work is exhausting after weeks of sistering joists and heavy lifting. Taking a week to just sit on the new boards and enjoy the evergreens makes that final stretch way easier.
How I finally solved drainage issues on a multi-level deck — steps that actually worked
Aug 30, 2026
Last reply: 15 hours ago
3 Replies
I used SkyLifts on a 40-foot span last summer and that extra airflow is a lifesaver for the ledger board, but I found that wind-driven rain in our climate still hits the siding if the overhang is too short. I ended up extending my roofline with a 24-inch soffit to keep the house dry. It adds weight, but it feels more secure when the storms roll in off the coast.
My take on the built-in planters is a bit different. I tried the rain chain drainage system but ended up with a massive clog from pine needles after just one season. I eventually lined the framing with EPDM pond liner and used it as a decorative sleeve for potted plants instead of filling it with soil. It saves the joists from constant moisture and makes it easier to swap out the greenery.
You are spot on about the physical toll. I rushed my skirting using Trex fascia boards while I was exhausted and missed my measurements by half an inch on the stairs. I really shoud have stepped back for a week. For the pergola, I used Simpson Strong-Tie bases set into the concrete—it’s the only way to sleep soundly when the wind hits 50 mph.
I am curious if you utilized a high-quality butyl-based joist tape across those sistered members, becuase the capillary action between two laminated boards in our humid enviornment essentially guarantees internal rot unless a physical barrier is established before the top-down fastening begins. While the structural integrity of those concrete-set pergola posts is undeniable, I find that many DIYers overlook the chemical compatibility between thier fasteners and the alkaline copper quaternary treatment in the lumber, wich can lead to catastrophic galvanic corrosion if you didn't specifically source 305 or 316 grade stainless steel screws for the decking and the hidden hardware.
I'm way out of my league here lol. I'm just looking at building a tiny 10x10 platform and all this talk about sistering joists sounds like a diffrent language. What does sistering acutally involve? Is it just bolting two boards togehter, or do you need special heavy-duty tools to get them lined up right? I’m mostly worried about my deck being wobbly if I don't get the foundation part exactly right like you did with those tubes.
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