Waterproofing under deck stairs and landing

[Sticktwig]

We recently had our deck replaced, after which I planned to study the yard and find a place to add a shed. It has since dawned on me enclosing the area beneath the landing and stairs will provide somewhere around 40 square feet without using up any more land.

I am considering building channels beneath the stairs using corrugated aluminum, but collecting the water beneath the landing seems tricky due to the odd dimensions when including the supports and the header. One option is to cut a piece of the aluminum to fit under the landing and send the bulk of water down onto the channels under the stairs. On either side, I could add a piece of guttering to carry that water, which would be drawing from about four square feet at max, down the supports to dump into the gravel I'll use to line the bottom of the area. Another option is to use a professional product to channel the water, but this seems overkill since it won't get me a better solution and won't be visible once the space is enclosed.

Does anyone else have a recommendation how I might approach this project? I've attached a picture of the landing so you can see how the supports and headers impact the design.

Thanks

 

[slownsteady]

I'm not sure what you mean by channels. There are systems for rain-proofing under a deck that you could look into, even if it is just for ideas.
However you choose to go, pay attention to where the water will drain to. I would want to move it further from the house (if possible) than you suggested. You may also want to consider the noise that rain will make on aluminum.

 

[nealtw]

Do the joist in the landing point toward the lower stairs. I have done it with solid vinyl soffit but it might depend how the stairs are attached to the landing, above and below stairs. We just let the water land just behind the bottom step into gravel.

 

[nealtw]

This is 2" pvc pipe with a Y and 2 end caps with part of the top cut off, set low enough for the collector to dump water into it the why is stuck thru 2 1/2" of 3" hole.
Add more white wood between posts to hide the collector.

 

[nealtw]

Run the pipe thru so it dump on to the next collector. You could add blocks between stringers to hide the collector

 

[nealtw]

don't no what happened my other posts I started with a 2" pvc pipe with end caps and a why that run thru the bulkhead with part of the top of the pipe cut away.

 

[Sticktwig]

We recently had our deck replaced, after which I planned to study the yard and find a place to add a shed. It has since dawned on me enclosing the area beneath the landing and stairs will provide somewhere around 40 square feet without using up any more land.

I am considering building channels beneath the stairs using corrugated aluminum, but collecting the water beneath the landing seems tricky due to the odd dimensions when including the supports and the header. One option is to cut a piece of the aluminum to fit under the landing and send the bulk of water down onto the channels under the stairs. On either side, I could add a piece of guttering to carry that water, which would be drawing from about four square feet at max, down the supports to dump into the gravel I'll use to line the bottom of the area. Another option is to use a professional product to channel the water, but this seems overkill since it won't get me a better solution and won't be visible once the space is enclosed.

Does anyone else have a recommendation how I might approach this project? I've attached a picture of the landing so you can see how the supports and headers impact the design.

Thanks

 

[Sticktwig]

I'm not sure what you mean by channels. There are systems for rain-proofing under a deck that you could look into, even if it is just for ideas.
However you choose to go, pay attention to where the water will drain to. I would want to move it further from the house (if possible) than you suggested. You may also want to consider the noise that rain will make on aluminum.

Thanks for the thoughts. By channels, I mean the valleys in the corrugated aluminum. Rain water will drip through the stair treads onto this, so I would just collect and send the water from the landing down that channel as well. I looked into products like Dryspace, but those are designed to be attractive and in my case this will all be out of sight.

You make a good point about the noise, but I don't think there will be much since there will be no directly rain onto the aluminum. I used an app to figure the total rainfall and at 1" per hour the total over that time will be 34 gallons. That's not a lot of water in that time, so suspect the flow won't make much noise either. If the aluminum shakes, I can try adding more supports.

Any of that sound wrong?

 

[Sticktwig]

don't no what happened my other posts I started with a 2" pvc pipe with end caps and a why that run thru the bulkhead with part of the top of the pipe cut away. View attachment 22810

I was debating using some form of guttering and still may as this may be the neatest option in that space. But instead of channeling the water under the stairs I could channel it into an existing underground pipe. Might do that with the whole thing. The deck crew added a concrete pour under the lowest step so I have an option of letting that receive the outflow but then worry about erosion over time.

I'm not yet certain, but getting a better idea. Hope to get permission from the association next week so I can get started and finish this up nicely without rushing before winter. But that's also another issue, I'm wondering how well this all holds up with our rainy winters in Virginia when ice builds up under the stairs.

 

[Sticktwig]

Accidentally discovered what I needed. Went to the hardware store for aluminum roofing to discover the sizes wouldn't work for the project without doubling up. Noticed these asphalt tiles and they worked perfectly. We ran 2x4's the length of the stair braces which both support the stairs and provide an interior structure to attach the boards. Dad and I were able to tuck the edges above the 2x4s and screw the tiles in using roofing roof screws. Some moisture may get through, but not enough to be a bother for what will be stored. Not bad for $40.